Update readme

- Added new output format: `m4b`, enabling chapter metadata in audiobooks. Special thanks to @jborza for implementing this feature in PR #10.
- Better approach for determining the correct configuration folder for Linux and MacOS, using platformdirs. (Fixes Docker issue #12)
- Improvements in documentation and code.

CHANGELOG.md

@@ -1,5 +1,3 @@
-- Added `abogen-cli` command for better troubleshooting and error handling.
-- Switched from setuptools to hatchling for packaging.
-- Added classifiers to the package metadata.
-- Fixed "No module named 'docopt'" and "setuptools.build_meta" import errors while using .bat installer in Windows, mentioned by @nigelp in https://github.com/denizsafak/abogen/issues/2 
-- Improvements in code and documentation.
+- Added new output format: `m4b`, enabling chapter metadata in audiobooks. Special thanks to @jborza for implementing this feature in PR #10.
+- Better approach for determining the correct configuration folder for Linux and MacOS, using platformdirs. (Fixes Docker issue #12)
+- Improvements in documentation and code.

README.md

@@ -1,7 +1,8 @@
 # abogen <img width="40px" title="abogen icon" src="https://raw.githubusercontent.com/denizsafak/abogen/refs/heads/main/abogen/assets/icon.ico" align="right" style="padding-left: 10px; padding-top:5px;">
 
 [![Build Status](https://github.com/denizsafak/abogen/actions/workflows/test_pip.yml/badge.svg)](https://github.com/denizsafak/abogen/actions)
-![Python Versions](https://img.shields.io/badge/python-3.10%20%7C%203.11%20%7C%203.12-blue?logo=python)
+[![GitHub Release](https://img.shields.io/github/v/release/denizsafak/abogen)](https://github.com/denizsafak/abogen/releases/latest)
+![abogen PyPi Python Versions](https://img.shields.io/pypi/pyversions/abogen)
 [![Operating Systems](https://img.shields.io/badge/os-windows%20%7C%20linux%20%7C%20macos%20-blue)](https://github.com/denizsafak/abogen/releases/latest)
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![License: MIT](https://img.shields.io/badge/License-MIT-maroon.svg)](https://opensource.org/licenses/MIT)
@@ -55,7 +56,7 @@ sudo dnf install espeak-ng
 # Install abogen
 pip install abogen
 ```
-> If you get "No matching distribution found" error, try installing it on supported Python (3.10 to 3.12). You can use [pyenv](https://github.com/pyenv/pyenv) to manage multiple Python versions easily in Linux.
+> If you get "No matching distribution found" error, try installing it on supported Python (3.10 to 3.12). You can use [pyenv](https://github.com/pyenv/pyenv) to manage multiple Python versions easily in Linux. Watch this [video](https://www.youtube.com/watch?v=MVyb-nI4KyI) by NetworkChuck for a quick guide.
 
 Then simply run by typing:
 
@@ -67,7 +68,7 @@ abogen
 1) Drag and drop any ePub, PDF, or text file (or use the built-in text editor)
 2) Configure the settings:
     - Set speech speed
-    - Select a voice
+    - Select a voice (or create a custom voice using voice mixer)
     - Select subtitle generation style (by sentence, word, etc.)
     - Select output format
     - Select where to save the output
@@ -82,19 +83,50 @@ Here’s Abogen in action: in this demo, it processes ∼3,000 characters of tex
 - **Supported formats**: `ePub`, `PDF`, or `.TXT` files (or use built-in text editor)
 - **Speed**: Adjust speech rate from `0.1x` to `2.0x`
 - **Voices**: First letter of the language code (e.g., `a` for American English, `b` for British English, etc.), second letter is for `m` for male and `f` for female.
+- **Voice mixer**: Create custom voices by mixing different voice models with a profile system.
 - **Generate subtitles**: `Disabled`, `Sentence`, `Sentence + Comma`, `1 word`, `2 words`, `3 words`, etc. (Represents the number of words in each subtitle entry)
-- **Output formats**: `.WAV`, `.FLAC`, or `.MP3`
+- **Output formats**: `.WAV`, `.FLAC`, `.MP3`, and `M4B (with chapters)` (Special thanks to [@jborza](https://github.com/jborza) for chapter support in PR [#10](https://github.com/denizsafak/abogen/pull/10))
 - **Save location**: `Save next to input file`, `Save to desktop`, or `Choose output folder`
 - **Chapter Control**: Select specific `chapters` from ePUBs or `chapters + pages` from PDFs.
 - **Options**:
-    - **Configure max words per subtitle**: Automatically configures the maximum number of words per subtitle entry.
+    - **Replace single newlines with spaces**: Replaces single newlines with spaces in the text. This is useful for texts that have imaginary line breaks.
+    - **Configure max words per subtitle**: Configures the maximum number of words per subtitle entry.
     - **Create desktop shortcut**: Creates a shortcut on your desktop for easy access.
     - **Open config.json directory**: Opens the directory where the configuration file is stored.
     - **Open temp directory**: Opens the temporary directory where converted text files are stored.
-    - **Clear all teporary files**: Deletes all temporary files created during the conversion process.
+    - **Clear all temporary files**: Deletes all temporary files created during the conversion process.
     - **Check for updates at startup**: Automatically checks for updates when the program starts.
 - **After conversion**: `Open file`, `Go to folder`, `New conversion`, or `Go back`.
 
+## `Voice Mixer`
+<img title="Abogen Voice Mixer" src='https://raw.githubusercontent.com/denizsafak/abogen/refs/heads/main/demo/voice_mixer.png'>
+
+With voice mixer, you can create custom voices by mixing different voice models. You can adjust the weight of each voice and save your custom voice as a profile for future use. The voice mixer allows you to create unique and personalized voices. (Huge thanks to [@jborza](https://github.com/jborza) for making this possible through his contributions in [#5](https://github.com/denizsafak/abogen/pull/5))
+
+## `About Chapter Markers`
+When you process ePUB or PDF files, abogen converts them into text files stored in your temporary directory. When you click "Edit," you're actually modifying these converted text files. In these text files, you'll notice tags that look like this:
+
+```
+<<CHAPTER_MARKER:Chapter Title>>
+```
+These are chapter markers. They are automatically added when you process ePUB or PDF files, based on the chapters you select. They serve an important purpose:
+-  Allow you to split the text into separate audio files for each chapter
+-  Save time by letting you reprocess only specific chapters if errors occur, rather than the entire file
+
+You can manually add these markers to plain text files for the same benefits. Simply include them in your text like this:
+
+```
+<<CHAPTER_MARKER:Introduction>>
+This is the beginning of my text...  
+
+<<CHAPTER_MARKER:Main Content>> 
+Here's another part...  
+```
+When you process the text file, abogen will detect these markers automatically and ask if you want to save each chapter separately and create a merged version.
+
+![Abogen Chapter Marker](https://raw.githubusercontent.com/denizsafak/abogen/refs/heads/main/demo/chapter_marker.png)
+
+
 ## `Supported Languages`
 ```
 # 🇺🇸 'a' => American English, 🇬🇧 'b' => British English
@@ -116,8 +148,49 @@ keep-open=yes
 --audio-device=openal
 --sub-margin-x=235
 --sub-pos=60
+# --- Audio Quality ---
+audio-spdif=ac3,dts,eac3,truehd,dts-hd
+audio-channels=auto
+audio-samplerate=48000
+volume-max=200
 ```
 
+## `Docker Guide`
+If you want to run Abogen in a Docker container:
+1) [Download the repository](https://github.com/denizsafak/abogen/archive/refs/heads/main.zip) and extract, or clone it using git.
+2) Go to `abogen` folder. You should see `Dockerfile` there.
+3) Open your termminal in that directory and run the following commands:
+
+```bash
+# Build the Docker image:
+docker build --progress plain -t abogen .
+
+# Note that building the image may take a while.
+# After building is complete, run the Docker container:
+
+# Windows
+docker run --name abogen -v %cd%:/shared -p 5800:5800 -p 5900:5900 --gpus all abogen
+
+# Linux
+docker run --name abogen -v $(pwd):/shared -p 5800:5800 -p 5900:5900 --gpus all abogen
+
+# MacOS
+docker run --name abogen -v $(pwd):/shared -p 5800:5800 -p 5900:5900 abogen
+
+# We expose port 5800 for use by a web browser, 5900 if you want to connect with a VNC client.
+```
+
+Abogen launches automatically inside the container. 
+- You can access it via a web browser at [http://localhost:5800](http://localhost:5800) or connect to it using a VNC client at `localhost:5900`.
+- You can use `/shared` directory to share files between your host and the container.
+- For later use, start it with `docker start abogen` and stop it with `docker stop abogen`.
+
+Known issues:
+- Audio preview is not working inside container (ALSA error).
+- `Open temp directory` and `Open configuration directory` options in settings not working. (Tried pcmanfm, did not work with abogen).
+
+(Special thanks to [@geo38](https://www.reddit.com/user/geo38/) from Reddit, who provided the Dockerfile and instructions in [this comment](https://www.reddit.com/r/selfhosted/comments/1k8x1yo/comment/mpe0bz8/).)
+
 ## `Similar Projects`
 Abogen is a standalone project, but it is inspired by and shares some similarities with other projects. Here are a few:
 - [audiblez](https://github.com/santinic/audiblez): Generate audiobooks from e-books. **(Has CLI and GUI support)**
@@ -127,9 +200,9 @@ Abogen is a standalone project, but it is inspired by and shares some similariti
 
 ## `Roadmap`
 - [ ] Improve PDF support for better text extraction.
-- [ ] Add chapter metadata for .m4a files using ffmpeg-bin.
+- [x] Add chapter metadata for .m4a files. (Issue [#9](https://github.com/denizsafak/abogen/issues/9), PR [#10](https://github.com/denizsafak/abogen/pull/10))
 - [ ] Add support for different languages in GUI.
-- [ ] Add voice formula feature that enables mixing different voice models. https://github.com/denizsafak/abogen/issues/1
+- [x] Add voice formula feature that enables mixing different voice models. (Issue [#1](https://github.com/denizsafak/abogen/issues/1), PR [#5](https://github.com/denizsafak/abogen/pull/5))
 - [ ] Add support for kokoro-onnx.
 - [ ] Add dark mode.
 
@@ -147,7 +220,8 @@ If you'd like to modify the code and contribute to development, you can [downloa
 ```bash
 # Go to the directory where you extracted the repository and run:
 pip install -e .      # Installs the package in editable mode
-python -m build       # Builds the package in dist folder
+pip install build     # Install the build package
+python -m build       # Builds the package in dist folder (optional)
 abogen                # Opens the GUI
 ```
 Feel free to explore the code and make any changes you like.
@@ -155,7 +229,9 @@ Feel free to explore the code and make any changes you like.
 ## `Credits`
 - Abogen uses [Kokoro](https://github.com/hexgrad/kokoro) for its high-quality, natural-sounding text-to-speech synthesis. Huge thanks to the Kokoro team for making this possible.
 - Thanks to [@wojiushixiaobai](https://github.com/wojiushixiaobai) for [Embedded Python](https://github.com/wojiushixiaobai/Python-Embed-Win64) packages. These modified packages include pip pre-installed, enabling Abogen to function as a standalone application without requiring users to separately install Python in Windows.
+- Thanks to creators of [EbookLib](https://github.com/aerkalov/ebooklib), a Python library for reading and writing ePub files, which is used for extracting text from ePub files.
 - Special thanks to the [PyQt](https://www.riverbankcomputing.com/software/pyqt/) team for providing the cross-platform GUI toolkit that powers Abogen's interface.
+- Icons: [US](https://icons8.com/icon/aRiu1GGi6Aoe/usa), [Great Britain](https://icons8.com/icon/t3NE3BsOAQwq/great-britain), [Spain](https://icons8.com/icon/ly7tzANRt33n/spain), [France](https://icons8.com/icon/3muzEmi4dpD5/france), [India](https://icons8.com/icon/esGVrxg9VCJ1/india), [Italy](https://icons8.com/icon/PW8KZnP7qXzO/italy), [Japan](https://icons8.com/icon/McQbrq9qaQye/japan), [Brazil](https://icons8.com/icon/zHmH8HpOmM90/brazil), [China](https://icons8.com/icon/Ej50Oe3crXwF/china), [Female](https://icons8.com/icon/uI49hxbpxTkp/female), [Male](https://icons8.com/icon/12351/male) and [Voice Id](https://icons8.com/icon/GskSeVoroQ7u/voice-id) icons by [Icons8](https://icons8.com/).
 
 ## `License`
 This project is available under the MIT License - see the [LICENSE](https://github.com/denizsafak/abogen/blob/main/LICENSE) file for details.

WINDOWS_INSTALL.bat

@@ -46,8 +46,7 @@ if exist "%VERSION_FILE%" (
     set "LOCAL_VERSION_CLEAN=!LOCAL_VERSION:.=!"
 
     :: First verify GitHub is accessible by checking HTTP status code
-    curl -s -o nul -w "%%{http_code}" "%VERSION_URL%" > "%TEMP%\abogen_http_status.txt"
-    set /p abogen_http_status=<"%TEMP%\abogen_http_status.txt"
+    for /f %%i in ('curl -s -o nul -w "%%{http_code}" "%VERSION_URL%"') do set abogen_http_status=%%i
     
     if not "!abogen_http_status!"=="200" (
         echo Failed to access GitHub repository ^(HTTP status: !abogen_http_status!^). Continuing with current version.
@@ -55,14 +54,8 @@ if exist "%VERSION_FILE%" (
     )
     
     :: Get the remote version (only if GitHub is accessible)
-    curl -s -o "%TEMP%\abogen_remote_version.txt" "%VERSION_URL%"
-    findstr "^" "%TEMP%\abogen_remote_version.txt" >nul 2>&1
-    if errorlevel 1 (
-        echo Failed to retrieve version information. Continuing with current version.
-        goto continue_with_current_version
-    )
+    for /f "delims=" %%i in ('curl -s "%VERSION_URL%"') do set abogen_remote_version=%%i
     
-    set /p abogen_remote_version=<"%TEMP%\abogen_remote_version.txt"
     if "!abogen_remote_version!"=="" (
         echo Empty version information received. Continuing with current version.
         goto continue_with_current_version
@@ -97,8 +90,7 @@ if exist "%VERSION_FILE%" (
         echo Downloading the latest update...
         
         :: Test the zip URL before downloading
-        curl -s -o nul -w "%%{http_code}" "%UPDATE_ZIP_URL%" > "%TEMP%\abogen_zip_status.txt"
-        set /p abogen_zip_status=<"%TEMP%\abogen_zip_status.txt"
+        for /f %%i in ('curl -s -o nul -w "%%{http_code}" "%UPDATE_ZIP_URL%"') do set abogen_zip_status=%%i
         
         if not "!abogen_zip_status!"=="302" (
             echo Failed to access update zip file ^(HTTP status: !abogen_zip_status!^). Continuing with current version.
@@ -137,7 +129,7 @@ if exist "%VERSION_FILE%" (
         )
     ) else (
         echo Current version: !LOCAL_VERSION!, Remote version: !abogen_remote_version!
-        echo You are usering the latest version.
+        echo You are using the latest version.
     )
 ) else (
     echo VERSION file not found. Cannot check for updates.
@@ -229,7 +221,7 @@ if errorlevel 1 (
 
 :: Install setup requirements
 echo Installing setup requirements...
-%PYTHON_CONSOLE_PATH% -m pip install --upgrade setuptools wheel sphinx hatchling --no-warn-script-location
+%PYTHON_CONSOLE_PATH% -m pip install --upgrade setuptools wheel sphinx hatchling progress --no-warn-script-location
 if errorlevel 1 (
     echo Failed to install setup requirements.
     pause

abogen/Dockerfile

@@ -0,0 +1,42 @@
+# Special thanks to @geo38 from Reddit, who provided this Dockerfile:
+# https://www.reddit.com/r/selfhosted/comments/1k8x1yo/comment/mpe0bz8/
+
+# Use a docker base image that runs a window manager that can be viewed
+# outside the image with a web browser or VNC client.
+# https://github.com/jlesage/docker-baseimage-gui
+FROM jlesage/baseimage-gui:debian-12-v4
+
+# Load stuff needed by abogen
+RUN apt-get update \
+ && apt-get install -y \
+        python3 \
+        python3-venv \
+        python3-pip \
+        python3-pyqt5 \
+        espeak-ng \
+ && apt-get clean \
+ && rm -rf /var/lib/apt/lists/*
+
+# The base image will run /startapp.sh on launch.
+#
+# The base image runs that script as user 'app' uid=1000. That user
+# does not exist in the base image but is created at run time.
+#
+# We need to install abogen in python venv (requirement of newer python3).
+#
+# The python venv has to be writable by the 'app' user as abogen dynamically
+# installs python packages, so create the venv as that user
+#
+# We intend to share the /shared directory with the host using a bind volume
+# in order to access any source files and the created files.
+
+RUN echo '#!/bin/bash\nsource /app/venv/bin/activate\nexec abogen' > /startapp.sh \
+  && chmod 555 /startapp.sh \
+  && mkdir /app /shared \
+  && chown 1000:1000 /app /shared \
+  && chmod 755 /app /shared
+USER 1000:1000
+RUN python3 -m venv /app/venv
+RUN /bin/bash -c "source /app/venv/bin/activate && pip install abogen"
+# Change back to user ROOT as the startup scripts inside base image needs it
+USER root

abogen/VERSION

@@ -1 +1 @@
-1.0.0
+1.0.5

abogen/constants.py

@@ -1,4 +1,4 @@
-from utils import get_version, get_user_config_path
+from utils import get_version
 
 # Program Information
 PROGRAM_NAME = "abogen"
@@ -102,16 +102,3 @@ SAMPLE_VOICE_TEXTS = {
     "p": "Este é um exemplo da voz selecionada.",
     "z": "这是所选语音的示例。",
 }
-
-# flags mapping for voice display
-FLAGS = {
-    "a": "🇺🇸",
-    "b": "🇬🇧",
-    "e": "🇪🇸",
-    "f": "🇫🇷",
-    "h": "🇮🇳",
-    "i": "🇮🇹",
-    "j": "🇯🇵",
-    "p": "🇧🇷",
-    "z": "🇨🇳",
-}

abogen/conversion.py

@@ -2,17 +2,38 @@ import os
 import re
 import tempfile
 import time
+import chardet
+import charset_normalizer
+from platformdirs import user_desktop_dir
 from PyQt5.QtCore import QThread, pyqtSignal, Qt
 from PyQt5.QtWidgets import QCheckBox, QVBoxLayout, QDialog, QLabel, QDialogButtonBox
 import soundfile as sf
 from utils import clean_text
 from constants import PROGRAM_NAME, LANGUAGE_DESCRIPTIONS, SAMPLE_VOICE_TEXTS
-
+from voice_formulas import get_new_voice
+import static_ffmpeg
+import threading  # for efficient waiting
 
 def get_sample_voice_text(lang_code):
     return SAMPLE_VOICE_TEXTS.get(lang_code, SAMPLE_VOICE_TEXTS["a"])
 
 
+def detect_encoding(file_path):
+    with open(file_path, "rb") as f:
+        raw_data = f.read()
+    detected_encoding = None
+    for detectors in (charset_normalizer, chardet):
+        try:
+            result = detectors.detect(raw_data)["encoding"]
+        except Exception:
+            continue
+        if result is not None:
+            detected_encoding = result
+            break
+    encoding = detected_encoding if detected_encoding else "utf-8"
+    return encoding.lower()
+
+
 class ChapterOptionsDialog(QDialog):
     def __init__(self, chapter_count, parent=None):
         super().__init__(parent)
@@ -108,6 +129,7 @@ class ConversionThread(QThread):
         use_gpu=True,
     ):  # Add use_gpu parameter
         super().__init__()
+        self._chapter_options_event = threading.Event()
         self.np = np_module
         self.KPipeline = kpipeline_class
         self.file_name = file_name
@@ -132,6 +154,9 @@ class ConversionThread(QThread):
         self.max_subtitle_words = 50  # Default value, will be overridden from GUI
 
     def run(self):
+        print(
+            f"\nVoice: {self.voice}\nLanguage: {self.lang_code}\nSpeed: {self.speed}\nGPU: {self.use_gpu}\nFile: {self.file_name}\nSubtitle mode: {self.subtitle_mode}\nOutput format: {self.output_format}\nSave option: {self.save_option}\n"
+        )
         try:
             # Show configuration
             self.log_updated.emit("Configuration:")
@@ -153,6 +178,8 @@ class ConversionThread(QThread):
             self.log_updated.emit(f"- Subtitle mode: {self.subtitle_mode}")
             self.log_updated.emit(f"- Output format: {self.output_format}")
             self.log_updated.emit(f"- Save option: {self.save_option}")
+            if self.replace_single_newlines:
+                self.log_updated.emit(f"- Replace single newlines: Yes")
 
             # Display save_chapters_separately flag if it's set
             if hasattr(self, "save_chapters_separately"):
@@ -183,7 +210,10 @@ class ConversionThread(QThread):
             if self.is_direct_text:
                 text = self.file_name  # Treat file_name as direct text input
             else:
-                with open(self.file_name, "r", encoding="utf-8") as file:
+                encoding = detect_encoding(self.file_name)
+                with open(
+                    self.file_name, "r", encoding=encoding, errors="replace"
+                ) as file:
                     text = file.read()
 
             # Clean up text using utility function
@@ -224,18 +254,12 @@ class ConversionThread(QThread):
                 and not self.chapter_options_set
             ):
 
-                self.waiting_for_user_input = True
-                # Emit signal to main thread to show dialog
+                # Emit signal to main thread and wait
                 self.chapters_detected.emit(total_chapters)
-
-                # Wait for chapter options to be set
-                while self.waiting_for_user_input and not self.cancel_requested:
-                    time.sleep(0.1)
-
+                self._chapter_options_event.wait()
                 if self.cancel_requested:
                     self.conversion_finished.emit("Cancelled", None)
                     return
-
                 self.chapter_options_set = True
 
             # Log all detected chapters at the beginning
@@ -256,11 +280,19 @@ class ConversionThread(QThread):
             base_path = self.display_path if self.display_path else self.file_name
             base_name = os.path.splitext(os.path.basename(base_path))[0]
             if self.save_option == "Save to Desktop":
-                parent_dir = os.path.join(os.path.expanduser("~"), "Desktop")
+                parent_dir = user_desktop_dir()
             elif self.save_option == "Save next to input file":
                 parent_dir = os.path.dirname(base_path)
             else:
                 parent_dir = self.output_folder or os.getcwd()
+            # Ensure the output folder exists, error if it doesn't
+            if not os.path.exists(parent_dir):
+                self.log_updated.emit(
+                    (
+                        f"Output folder does not exist: {parent_dir}",
+                        "red",
+                    )
+                )
             # Find a unique suffix for both folder and merged file, always
             counter = 1
             while True:
@@ -303,6 +335,12 @@ class ConversionThread(QThread):
             # Initialize current segment counter
             current_segment = 0
 
+            # Initialize chapter times
+            chapters_time = [
+                {"chapter": chapter[0], "start": 0.0, "end": 0.0}
+                for chapter in chapters
+            ]
+
             # Instead of processing the whole text, process by chapter
             for chapter_idx, (chapter_name, chapter_text) in enumerate(chapters, 1):
                 if total_chapters > 1:
@@ -318,11 +356,22 @@ class ConversionThread(QThread):
                 chapter_subtitle_entries = []
                 chapter_current_time = 0.0
 
+                # chapter start time
+                chapter_time = chapters_time[chapter_idx - 1]
+                chapter_time["start"] = current_time
+
                 # Set split_pattern to \n+ which will split on one or more newlines
                 split_pattern = r"\n+"
+
+                # Check if the voice is a formula and load it if necessary
+                if "*" in self.voice:
+                    loaded_voice = get_new_voice(tts, self.voice, self.use_gpu)
+                else:
+                    loaded_voice = self.voice
+
                 for result in tts(
                     chapter_text,
-                    voice=self.voice,
+                    voice=loaded_voice,
                     speed=self.speed,
                     split_pattern=split_pattern,
                 ):
@@ -424,6 +473,9 @@ class ConversionThread(QThread):
                     # Update progress more frequently (after each result)
                     self.progress_updated.emit(percent, etr_str)
 
+                # Update chapter end time
+                chapter_time["end"] = current_time
+
                 # Save the individual chapter output if save_chapters_separately is enabled
                 if (
                     save_chapters_separately
@@ -440,14 +492,20 @@ class ConversionThread(QThread):
 
                     # Concatenate chapter audio and save
                     chapter_audio = self.np.concatenate(chapter_audio_segments)
+                    # If output format is m4b, save chapter as wav
+                    chapter_ext = self.output_format
+                    chapter_format = self.output_format
+                    if self.output_format == "m4b":
+                        chapter_ext = "wav"
+                        chapter_format = "wav"
                     chapter_out_path = os.path.join(
-                        chapters_out_dir, f"{chapter_filename}.{self.output_format}"
+                        chapters_out_dir, f"{chapter_filename}.{chapter_ext}"
                     )
                     sf.write(
                         chapter_out_path,
                         chapter_audio,
                         24000,
-                        format=self.output_format,
+                        format=chapter_format,
                     )
 
                     # Generate .srt subtitle file for chapter if not Disabled
@@ -455,7 +513,9 @@ class ConversionThread(QThread):
                         chapter_srt_path = os.path.join(
                             chapters_out_dir, f"{chapter_filename}.srt"
                         )
-                        with open(chapter_srt_path, "w", encoding="utf-8") as srt_file:
+                        with open(
+                            chapter_srt_path, "w", encoding="utf-8", errors="replace"
+                        ) as srt_file:
                             for i, (start, end, text) in enumerate(
                                 chapter_subtitle_entries, 1
                             ):
@@ -486,6 +546,7 @@ class ConversionThread(QThread):
                 or not self.save_chapters_separately
                 or getattr(self, "merge_chapters_at_end", True)
             )
+            m4b_picked = False  # Ensure m4b_picked is always defined
             if audio_segments and merge_chapters:
                 self.log_updated.emit("\nFinalizing audio file...\n")
                 audio = self.np.concatenate(audio_segments)
@@ -494,9 +555,20 @@ class ConversionThread(QThread):
                 out_filename = f"{base_name}{suffix}.{self.output_format}"
                 out_path = os.path.join(out_dir, out_filename)
                 srt_path = os.path.splitext(out_path)[0] + ".srt"
+
+                # in case the user picked m4b format, we need to change the output format to wav
+                if self.output_format == "m4b":
+                    out_path = os.path.splitext(out_path)[0] + ".wav"
+                    self.output_format = "wav"
+                    m4b_picked = True
                 sf.write(out_path, audio, 24000, format=self.output_format)
+                if m4b_picked:
+                    out_path = self._generate_m4b_with_chapters(out_path, chapters_time)
+
                 if self.subtitle_mode != "Disabled":
-                    with open(srt_path, "w", encoding="utf-8") as srt_file:
+                    with open(
+                        srt_path, "w", encoding="utf-8", errors="replace"
+                    ) as srt_file:
                         for i, (start, end, text) in enumerate(subtitle_entries, 1):
                             srt_file.write(
                                 f"{i}\n{self._srt_time(start)} --> {self._srt_time(end)}\n{text}\n\n"
@@ -532,6 +604,57 @@ class ConversionThread(QThread):
         self.save_chapters_separately = options["save_chapters_separately"]
         self.merge_chapters_at_end = options["merge_chapters_at_end"]
         self.waiting_for_user_input = False
+        self._chapter_options_event.set()
+
+    def _generate_m4b_with_chapters(self, out_path, chapters_time):
+        # If there is only one chapter, skip adding chapters and just return the wav file path
+        if not chapters_time or len(chapters_time) <= 1:
+            self.log_updated.emit(
+                ("File contains only one chapter or no chapters were detected. The audio will be saved as a standard .wav file instead.\n", "red")
+            )
+            return out_path
+        # generate chapters.txt in the same folder as the output file
+        chapters_info_path = os.path.splitext(out_path)[0] + "_chapters.txt"
+        with open(chapters_info_path, "w", encoding="utf-8") as f:
+            f.write(';FFMETADATA1\n') # required header for ffmpeg
+            for chapter in chapters_time:
+                f.write(f"[CHAPTER]\n")
+                f.write(f"TIMEBASE=1/10\n")
+                # use 10th of second for start/end time
+                f.write(f"START={int(chapter["start"]*10)}\n")
+                f.write(f"END={int(chapter["end"]*10)}\n")
+                f.write(f"title={chapter["chapter"]}\n\n")
+        # call ffmpeg to merge the chapters into the output file
+        # ffmpeg installed on first call to add_paths()
+        static_ffmpeg.add_paths()
+        import subprocess
+        out_path_m4b = os.path.splitext(out_path)[0] + ".m4b"
+        # ffmpeg -i input.m4b -i ch.txt -map 0:a -map_chapters 1 output.m4b
+        ffmpeg_cmd = [
+            "ffmpeg",
+            "-i", out_path,
+            "-i", chapters_info_path,
+            "-map", "0:a",
+            "-map_chapters", "1",
+            out_path_m4b
+        ]
+        
+        self.log_updated.emit("Adding chapters to the audio file...\n")
+        result = subprocess.run(ffmpeg_cmd, capture_output=True, text=True)
+        # Check for errors in the ffmpeg command
+        if result.returncode != 0:
+            self.log_updated.emit((f"FFmpeg error: {result.stderr}", "red"))
+            # Log error but continue with original file
+            self.log_updated.emit(("Falling back to the original audio file without chapters\n", "orange"))
+            return out_path
+        else:
+            self.log_updated.emit(("Successfully added chapters to the audio file.\n", "green"))
+        
+        # delete the chapters path and original (wav) file
+        os.remove(chapters_info_path)
+        os.remove(out_path)
+        # the new file is in m4b format - use that for messages
+        return out_path_m4b
 
     def _srt_time(self, t):
         """Helper function to format time for SRT files"""
@@ -639,7 +762,14 @@ class VoicePreviewThread(QThread):
     error = pyqtSignal(str)
 
     def __init__(
-        self, np_module, kpipeline_class, lang_code, voice, speed, parent=None
+        self,
+        np_module,
+        kpipeline_class,
+        lang_code,
+        voice,
+        speed,
+        use_gpu=False,
+        parent=None,
     ):
         super().__init__(parent)
         self.np_module = np_module
@@ -647,17 +777,26 @@ class VoicePreviewThread(QThread):
         self.lang_code = lang_code
         self.voice = voice
         self.speed = speed
-        self.temp_wav = None
+        self.use_gpu = use_gpu
 
     def run(self):
+        print(
+            f"\nVoice: {self.voice}\nLanguage: {self.lang_code}\nSpeed: {self.speed}\nGPU: {self.use_gpu}\n"
+        )
         try:
+            device = "cuda" if self.use_gpu else "cpu"
             tts = self.kpipeline_class(
-                lang_code=self.lang_code, repo_id="hexgrad/Kokoro-82M"
+                lang_code=self.lang_code, repo_id="hexgrad/Kokoro-82M", device=device
             )
+            # Enable voice formula support for preview
+            if "*" in self.voice:
+                loaded_voice = get_new_voice(tts, self.voice, self.use_gpu)
+            else:
+                loaded_voice = self.voice
             sample_text = get_sample_voice_text(self.lang_code)
             audio_segments = []
             for result in tts(
-                sample_text, voice=self.voice, speed=self.speed, split_pattern=None
+                sample_text, voice=loaded_voice, speed=self.speed, split_pattern=None
             ):
                 audio_segments.append(result.audio)
             if audio_segments:

abogen/gui.py

@@ -3,6 +3,7 @@ import time
 import tempfile
 import platform
 import base64
+import re
 from PyQt5.QtWidgets import (
     QApplication,
     QWidget,
@@ -65,11 +66,13 @@ from constants import (
     GITHUB_URL,
     PROGRAM_DESCRIPTION,
     LANGUAGE_DESCRIPTIONS,
-    FLAGS,
     VOICES_INTERNAL,
     SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION,
 )
 from threading import Thread
+from voice_formula_gui import VoiceFormulaDialog
+from platformdirs import user_desktop_dir
+from voice_profiles import load_profiles
 
 # Import ctypes for Windows-specific taskbar icon
 if platform.system() == "Windows":
@@ -456,8 +459,17 @@ class abogen(QWidget):
         self.selected_chapters = set()
         self.last_opened_book_path = None  # Track the last opened book path
         self.last_output_path = None
-        self.selected_voice = self.config.get("selected_voice", "af_heart")
-        self.selected_lang = self.selected_voice[0]
+        # Only one of selected_profile_name or selected_voice should be set
+        self.selected_profile_name = self.config.get("selected_profile_name")
+        self.selected_voice = None
+        self.selected_lang = None
+        self.mixed_voice_state = None
+        if self.selected_profile_name:
+            self.selected_voice = None
+            self.selected_lang = None
+        else:
+            self.selected_voice = self.config.get("selected_voice", "af_heart")
+            self.selected_lang = self.selected_voice[0] if self.selected_voice else None
         self.is_converting = False
         self.subtitle_mode = self.config.get("subtitle_mode", "Sentence")
         self.max_subtitle_words = self.config.get(
@@ -465,8 +477,9 @@ class abogen(QWidget):
         )  # Default max words per subtitle
         self.selected_format = self.config.get("selected_format", "wav")
         self.use_gpu = self.config.get(
-            "use_gpu", True
-        )  # Load GPU setting with default True
+            "use_gpu", True  # Load GPU setting with default True
+        )
+        self.replace_single_newlines = self.config.get("replace_single_newlines", False)
         self._pending_close_event = None
         self.gpu_ok = False  # Initialize GPU availability status
 
@@ -485,17 +498,32 @@ class abogen(QWidget):
         self.initUI()
         self.speed_slider.setValue(int(self.config.get("speed", 1.00) * 100))
         self.update_speed_label()
-        idx = self.voice_combo.findData(self.selected_voice)
+        # Set initial selection: prefer profile, else voice
+        idx = -1
+        if self.selected_profile_name:
+            idx = self.voice_combo.findData(f"profile:{self.selected_profile_name}")
+        elif self.selected_voice:
+            idx = self.voice_combo.findData(self.selected_voice)
         if idx >= 0:
             self.voice_combo.setCurrentIndex(idx)
+            # If a profile is selected at startup, load voices and language
+            if self.selected_profile_name:
+                from voice_profiles import load_profiles
+
+                entry = load_profiles().get(self.selected_profile_name, {})
+                if isinstance(entry, dict):
+                    self.mixed_voice_state = entry.get("voices", [])
+                    self.selected_lang = entry.get("language")
+                else:
+                    self.mixed_voice_state = entry
+                    self.selected_lang = entry[0][0] if entry and entry[0] else None
         if self.save_option == "Choose output folder" and self.selected_output_folder:
             self.save_path_label.setText(self.selected_output_folder)
             self.save_path_label.show()
         self.subtitle_combo.setCurrentText(self.subtitle_mode)
-        # Enable/disable subtitle options based on selected language
-        self.subtitle_combo.setEnabled(
-            self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
-        )
+        # Enable/disable subtitle options based on selected language (profile or voice)
+        enable = self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
+        self.subtitle_combo.setEnabled(enable)
         # loading gif for preview button
         loading_gif_path = get_resource_path("abogen.assets", "loading.gif")
         if loading_gif_path:
@@ -555,19 +583,26 @@ class abogen(QWidget):
         voice_layout.addWidget(QLabel("Select Voice:", self))
         voice_row = QHBoxLayout()
         self.voice_combo = QComboBox(self)
-        for v in VOICES_INTERNAL:
-            flag = FLAGS.get(v[0], "")
-            self.voice_combo.addItem(f"{flag} {v}", v)
+        self.voice_combo.currentIndexChanged.connect(self.on_voice_combo_changed)
         self.voice_combo.setStyleSheet(
             "QComboBox { min-height: 20px; padding: 6px 12px; }"
         )
-        self.voice_combo.currentIndexChanged.connect(self.on_voice_changed)
         self.voice_combo.setToolTip(
             "The first character represents the language:\n"
             '"a" => American English\n"b" => British English\n"e" => Spanish\n"f" => French\n"h" => Hindi\n"i" => Italian\n"j" => Japanese\n"p" => Brazilian Portuguese\n"z" => Mandarin Chinese\nThe second character represents the gender:\n"m" => Male\n"f" => Female'
         )
         voice_row.addWidget(self.voice_combo)
 
+        # Voice formula button
+        self.btn_voice_formula_mixer = QPushButton(self)
+        mixer_icon_path = get_resource_path("abogen.assets", "voice_mixer.png")
+        self.btn_voice_formula_mixer.setIcon(QIcon(mixer_icon_path))
+        self.btn_voice_formula_mixer.setToolTip("Mix and match voices")
+        self.btn_voice_formula_mixer.setFixedSize(40, 36)
+        self.btn_voice_formula_mixer.setStyleSheet("QPushButton { padding: 6px 12px; }")
+        self.btn_voice_formula_mixer.clicked.connect(self.show_voice_formula_dialog)
+        voice_row.addWidget(self.btn_voice_formula_mixer)
+
         # Play/Stop icons
         def make_icon(color, shape):
             pix = QPixmap(20, 20)
@@ -626,23 +661,27 @@ class abogen(QWidget):
         )
         self.subtitle_combo.setCurrentText(self.subtitle_mode)
         self.subtitle_combo.currentTextChanged.connect(self.on_subtitle_mode_changed)
-        # Enable/disable subtitle options based on selected language
-        self.subtitle_combo.setEnabled(
-            self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
-        )
+        # Enable/disable subtitle options based on selected language (profile or voice)
+        enable = self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
+        self.subtitle_combo.setEnabled(enable)
         subtitle_layout.addWidget(self.subtitle_combo)
         controls_layout.addLayout(subtitle_layout)
         # Output format
         format_layout = QVBoxLayout()
         format_layout.addWidget(QLabel("Output Format:", self))
         self.format_combo = QComboBox(self)
-        self.format_combo.setStyleSheet(
-            "QComboBox { min-height: 20px; padding: 6px 12px; }"
+        self.format_combo.setStyleSheet("QComboBox { min-height: 20px; padding: 6px 12px; }")
+        # Add items with display labels and underlying keys
+        for key, label in [("wav","wav"),("flac","flac"),("mp3","mp3"),("m4b","m4b (with chapters)")]:
+            self.format_combo.addItem(label, key)
+        # Initialize selection by matching saved key
+        idx = self.format_combo.findData(self.selected_format)
+        if idx >= 0:
+            self.format_combo.setCurrentIndex(idx)
+        # Map selection back to key on change
+        self.format_combo.currentIndexChanged.connect(
+            lambda i: self.on_format_changed(self.format_combo.itemData(i))
         )
-        format_options = ["wav", "flac", "mp3"]
-        self.format_combo.addItems(format_options)
-        self.format_combo.setCurrentText(self.selected_format)
-        self.format_combo.currentTextChanged.connect(self.on_format_changed)
         format_layout.addWidget(self.format_combo)
         controls_layout.addLayout(format_layout)
         # Save location
@@ -751,6 +790,7 @@ class abogen(QWidget):
         container_layout.addWidget(self.finish_widget)
         outer_layout.addWidget(container)
         self.setLayout(outer_layout)
+        self.populate_profiles_in_voice_combo()
 
     def open_file_dialog(self):
         if self.is_converting:
@@ -933,6 +973,87 @@ class abogen(QWidget):
         else:
             self.subtitle_combo.setEnabled(False)
 
+    def on_voice_combo_changed(self, index):
+        data = self.voice_combo.itemData(index)
+        if isinstance(data, str) and data.startswith("profile:"):
+            pname = data.split(":", 1)[1]
+            self.selected_profile_name = pname
+            from voice_profiles import load_profiles
+
+            entry = load_profiles().get(pname, {})
+            # set mixed voices and language
+            if isinstance(entry, dict):
+                self.mixed_voice_state = entry.get("voices", [])
+                self.selected_lang = entry.get("language")
+            else:
+                self.mixed_voice_state = entry
+                self.selected_lang = entry[0][0] if entry and entry[0] else None
+            self.selected_voice = None
+            self.config["selected_profile_name"] = pname
+            self.config.pop("selected_voice", None)
+            save_config(self.config)
+            # enable subtitles based on profile language
+            self.subtitle_combo.setEnabled(
+                self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
+            )
+        else:
+            self.mixed_voice_state = None
+            self.selected_profile_name = None
+            self.selected_voice, self.selected_lang = data, data[0]
+            self.config["selected_voice"] = data
+            if "selected_profile_name" in self.config:
+                del self.config["selected_profile_name"]
+            save_config(self.config)
+            if self.selected_lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION:
+                self.subtitle_combo.setEnabled(True)
+                self.subtitle_mode = self.subtitle_combo.currentText()
+            else:
+                self.subtitle_combo.setEnabled(False)
+
+    def update_subtitle_combo_for_profile(self, profile_name):
+        from voice_profiles import load_profiles
+
+        entry = load_profiles().get(profile_name, {})
+        lang = entry.get("language") if isinstance(entry, dict) else None
+        enable = lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
+        self.subtitle_combo.setEnabled(enable)
+
+    def populate_profiles_in_voice_combo(self):
+        # preserve current voice or profile
+        current = self.voice_combo.currentData()
+        self.voice_combo.blockSignals(True)
+        self.voice_combo.clear()
+        # re-add profiles
+        profile_icon = QIcon(get_resource_path("abogen.assets", "profile.png"))
+        for pname in load_profiles().keys():
+            self.voice_combo.addItem(profile_icon, pname, f"profile:{pname}")
+        # re-add voices
+        for v in VOICES_INTERNAL:
+            icon = QIcon()
+            flag_path = get_resource_path("abogen.assets.flags", f"{v[0]}.png")
+            if flag_path and os.path.exists(flag_path):
+                icon = QIcon(flag_path)
+            self.voice_combo.addItem(icon, f"{v}", v)
+        # restore selection
+        idx = -1
+        if self.selected_profile_name:
+            idx = self.voice_combo.findData(f"profile:{self.selected_profile_name}")
+        elif current:
+            idx = self.voice_combo.findData(current)
+        if idx >= 0:
+            self.voice_combo.setCurrentIndex(idx)
+            # Also update subtitle combo for selected profile
+            data = self.voice_combo.itemData(idx)
+            if isinstance(data, str) and data.startswith("profile:"):
+                pname = data.split(":", 1)[1]
+                self.update_subtitle_combo_for_profile(pname)
+        self.voice_combo.blockSignals(False)
+        # If no profiles exist, clear selected_profile_name from config
+        if not load_profiles():
+            if "selected_profile_name" in self.config:
+                del self.config["selected_profile_name"]
+                save_config(self.config)
+
     def convert_input_box_to_log(self):
         self.input_box.hide()
         self.log_text.show()
@@ -1038,11 +1159,32 @@ class abogen(QWidget):
                 else self.subtitle_mode
             )
 
+            # if voice formula is not None, use the selected voice
+            if self.mixed_voice_state:
+                formula_components = [
+                    f"{name}*{weight}" for name, weight in self.mixed_voice_state
+                ]
+                voice_formula = " + ".join(filter(None, formula_components))
+            else:
+                voice_formula = self.selected_voice
+            # determine selected language: use profile setting if profile selected, else voice code
+            if self.selected_profile_name:
+                from voice_profiles import load_profiles
+
+                entry = load_profiles().get(self.selected_profile_name, {})
+                selected_lang = entry.get("language")
+            else:
+                selected_lang = self.selected_voice[0] if self.selected_voice else None
+            # fallback: extract from formula if missing
+            if not selected_lang:
+                m = re.search(r"\b([a-z])", voice_formula)
+                selected_lang = m.group(1) if m else None
+
             self.conversion_thread = ConversionThread(
                 self.selected_file,
-                self.selected_lang,
+                selected_lang,
                 speed,
-                self.selected_voice,
+                voice_formula,
                 self.save_option,
                 self.selected_output_folder,
                 subtitle_mode=actual_subtitle_mode,
@@ -1059,6 +1201,10 @@ class abogen(QWidget):
             self.conversion_thread.file_size_str = file_size_str
             # Pass max_subtitle_words from config
             self.conversion_thread.max_subtitle_words = self.max_subtitle_words
+            # Pass replace_single_newlines setting
+            self.conversion_thread.replace_single_newlines = (
+                self.replace_single_newlines
+            )
             # Pass chapter count for EPUB or PDF files
             if self.selected_file_type in ["epub", "pdf"] and hasattr(
                 self, "selected_chapters"
@@ -1276,7 +1422,6 @@ class abogen(QWidget):
         if self.preview_playing:
             try:
                 import pygame
-
                 pygame.mixer.music.stop()
             except Exception:
                 pass
@@ -1289,9 +1434,22 @@ class abogen(QWidget):
         self.btn_preview.setEnabled(False)
         self.btn_preview.setToolTip("Loading...")
         self.voice_combo.setEnabled(False)
+        self.btn_voice_formula_mixer.setEnabled(False)  # Disable mixer button
         self.btn_start.setEnabled(False)  # Disable start button during preview
-        # start loading animation
-        self.loading_movie.start()
+        
+        # Start loading animation - ensure signal connection is always active
+        if hasattr(self, 'loading_movie'):
+            # Disconnect previous connections to avoid multiple connections
+            try:
+                self.loading_movie.frameChanged.disconnect()
+            except TypeError:
+                pass  # Ignore error if not connected
+            
+            # Reconnect the signal
+            self.loading_movie.frameChanged.connect(
+                lambda: self.btn_preview.setIcon(QIcon(self.loading_movie.currentPixmap()))
+            )
+            self.loading_movie.start()
 
         def pipeline_loaded_callback(np_module, kpipeline_class, error):
             self._on_pipeline_loaded_for_preview(np_module, kpipeline_class, error)
@@ -1303,23 +1461,46 @@ class abogen(QWidget):
         # stop loading animation and restore icon on error
         if error:
             self.loading_movie.stop()
-            self.btn_preview.setIcon(self.play_icon)
             self._show_error_message_box(
                 "Loading Error", f"Error loading numpy or KPipeline: {error}"
             )
+            self.btn_preview.setIcon(self.play_icon)
             self.btn_preview.setEnabled(True)
             self.btn_preview.setToolTip("Preview selected voice")
             self.voice_combo.setEnabled(True)
+            self.btn_voice_formula_mixer.setEnabled(True)  # Re-enable mixer button
             self.btn_start.setEnabled(True)  # Re-enable start button on error
             return
 
-        lang, voice, speed = (
-            self.selected_voice[0],
-            self.selected_voice,
-            self.speed_slider.value() / 100.0,
-        )
+        # Support preview for voice profiles
+        speed = self.speed_slider.value() / 100.0
+        if self.mixed_voice_state:
+            # Build voice formula string
+            components = [f"{name}*{weight}" for name, weight in self.mixed_voice_state]
+            voice = " + ".join(filter(None, components))
+            # determine language: use profile setting if available, else first voice code
+            if self.selected_profile_name:
+                from voice_profiles import load_profiles
+
+                entry = load_profiles().get(self.selected_profile_name, {})
+                lang = entry.get("language")
+            else:
+                lang = None
+            if not lang and self.mixed_voice_state:
+                lang = (
+                    self.mixed_voice_state[0][0][0]
+                    if self.mixed_voice_state and self.mixed_voice_state[0][0]
+                    else None
+                )
+        else:
+            lang = self.selected_voice[0]
+            voice = self.selected_voice
+
+        # use same gpu/cpu logic as in conversion
+        gpu_msg, gpu_ok = get_gpu_acceleration(self.use_gpu)
+
         self.preview_thread = VoicePreviewThread(
-            np_module, kpipeline_class, lang, voice, speed
+            np_module, kpipeline_class, lang, voice, speed, gpu_ok 
         )
         self.preview_thread.finished.connect(self._play_preview_audio)
         self.preview_thread.error.connect(self._preview_error)
@@ -1329,13 +1510,15 @@ class abogen(QWidget):
         temp_wav = self.preview_thread.temp_wav
         if not temp_wav:
             self.loading_movie.stop()
-            self.btn_preview.setIcon(self.play_icon)
+
             self._show_error_message_box(
                 "Preview Error", "Preview error: No audio generated."
             )
-            self.btn_preview.setEnabled(True)
+            self.btn_preview.setIcon(self.play_icon)
             self.btn_preview.setToolTip("Preview selected voice")
+            self.btn_preview.setEnabled(True)
             self.voice_combo.setEnabled(True)
+            self.btn_voice_formula_mixer.setEnabled(True)  # Re-enable mixer button
             self.btn_start.setEnabled(True)
             return
         # stop loading animation, switch to stop icon
@@ -1381,10 +1564,16 @@ class abogen(QWidget):
 
     def _preview_cleanup(self):
         self.preview_playing = False
+        self.loading_movie.stop()
+        try:
+            self.loading_movie.frameChanged.disconnect()
+        except Exception:
+            pass  # Ignore error if not connected
         self.btn_preview.setIcon(self.play_icon) 
         self.btn_preview.setToolTip("Preview selected voice")
         self.btn_preview.setEnabled(True)
         self.voice_combo.setEnabled(True)
+        self.btn_voice_formula_mixer.setEnabled(True)  # Re-enable mixer button
         self.btn_start.setEnabled(True)
 
     def _preview_error(self, msg):
@@ -1499,6 +1688,13 @@ class abogen(QWidget):
         """Show a dropdown menu for settings options."""
         menu = QMenu(self)
 
+        # Add replace single newlines option
+        newline_action = QAction("Replace single newlines with spaces", self)
+        newline_action.setCheckable(True)
+        newline_action.setChecked(self.replace_single_newlines)
+        newline_action.triggered.connect(self.toggle_replace_single_newlines)
+        menu.addAction(newline_action)
+
         # Add max words per subtitle option
         max_words_action = QAction("Configure max words per subtitle", self)
         max_words_action.triggered.connect(self.set_max_subtitle_words)
@@ -1514,7 +1710,7 @@ class abogen(QWidget):
             menu.addAction(add_shortcut_action)
 
         # Add reveal config option
-        reveal_config_action = QAction("Open config.json directory", self)
+        reveal_config_action = QAction("Open configuration directory", self)
         reveal_config_action.triggered.connect(self.reveal_config_in_explorer)
         menu.addAction(reveal_config_action)
 
@@ -1545,6 +1741,11 @@ class abogen(QWidget):
 
         menu.exec_(self.settings_btn.mapToGlobal(QPoint(0, self.settings_btn.height())))
 
+    def toggle_replace_single_newlines(self, checked):
+        self.replace_single_newlines = checked
+        self.config["replace_single_newlines"] = checked
+        save_config(self.config)
+
     def reveal_config_in_explorer(self):
         """Open the configuration file location in file explorer."""
         from utils import get_user_config_path
@@ -1582,7 +1783,7 @@ class abogen(QWidget):
 
         try:
             # where to put the .lnk
-            desktop = os.path.join(os.environ.get("USERPROFILE", ""), "Desktop")
+            desktop = user_desktop_dir()
             shortcut_path = os.path.join(desktop, "abogen.lnk")
 
             # target exe
@@ -1642,6 +1843,49 @@ class abogen(QWidget):
         self.config["check_updates"] = checked
         save_config(self.config)
 
+    def show_voice_formula_dialog(self):
+        from voice_profiles import load_profiles
+        profiles = load_profiles()
+        initial_state = None
+        selected_profile = self.selected_profile_name
+        if selected_profile:
+            entry = profiles.get(selected_profile, {})
+            if isinstance(entry, dict):
+                initial_state = entry.get("voices", [])
+            else:
+                initial_state = entry
+        elif self.mixed_voice_state is not None:
+            initial_state = self.mixed_voice_state
+        elif self.selected_voice:
+            # If a single voice is selected, default to first profile if available
+            if profiles:
+                first_profile = next(iter(profiles))
+                entry = profiles[first_profile]
+                selected_profile = first_profile
+                if isinstance(entry, dict):
+                    initial_state = entry.get("voices", [])
+                else:
+                    initial_state = entry
+            else:
+                initial_state = []
+        else:
+            initial_state = []
+        dialog = VoiceFormulaDialog(
+            self, initial_state=initial_state, selected_profile=selected_profile
+        )
+        if dialog.exec_() == QDialog.Accepted:
+            if dialog.current_profile:
+                self.selected_profile_name = dialog.current_profile
+                self.config["selected_profile_name"] = dialog.current_profile
+                if "selected_voice" in self.config:
+                    del self.config["selected_voice"]
+                save_config(self.config)
+                self.populate_profiles_in_voice_combo()
+                idx = self.voice_combo.findData(f"profile:{dialog.current_profile}")
+                if idx >= 0:
+                    self.voice_combo.setCurrentIndex(idx)
+            self.mixed_voice_state = dialog.get_selected_voices()
+
     def show_about_dialog(self):
         """Show an About dialog with program information including GitHub link."""
         # Get application icon for dialog

abogen/utils.py

@@ -32,6 +32,14 @@ def get_resource_path(package, resource):
     except (ImportError, FileNotFoundError):
         pass
 
+    # Always try to resolve as a relative path from this file
+    parts = package.split(".")
+    rel_path = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), *parts[1:], resource
+    )
+    if os.path.exists(rel_path):
+        return rel_path
+
     # Fallback to local file system
     try:
         # Extract the subdirectory from package name (e.g., 'assets' from 'abogen.assets')
@@ -50,7 +58,7 @@ def get_resource_path(package, resource):
 def get_version():
     """Return the current version of the application."""
     try:
-        with open(get_resource_path("abogen", "VERSION"), "r") as f:
+        with open(get_resource_path("/", "VERSION"), "r") as f:
             return f.read().strip()
     except Exception:
         return "Unknown"
@@ -58,10 +66,19 @@ def get_version():
 
 # Define config path
 def get_user_config_path():
-    if os.name == "nt":
-        config_dir = os.path.join(os.environ["APPDATA"], "abogen")
+    from platformdirs import user_config_dir
+    # TODO Config directory is changed for Linux and MacOS. But if old config exists, it will be used.
+    # On non‑Windows, prefer ~/.config/abogen if it already exists
+    if platform.system() != "Windows":
+        custom_dir = os.path.join(os.path.expanduser("~"), ".config", "abogen")
+        if os.path.exists(custom_dir):
+            config_dir = custom_dir
+        else:
+            config_dir = user_config_dir("abogen", appauthor=False, roaming=True)
     else:
-        config_dir = os.path.join(os.path.expanduser("~"), ".config", "abogen")
+        # Windows and fallback case
+        config_dir = user_config_dir("abogen", appauthor=False, roaming=True)
+
     os.makedirs(config_dir, exist_ok=True)
     return os.path.join(config_dir, "config.json")
 
@@ -69,15 +86,18 @@ def get_user_config_path():
 _sleep_procs = {"Darwin": None, "Linux": None}  # Store sleep prevention processes
 
 
-def clean_text(text):
-    # Trim spaces and tabs at the start and end of each line, preserving blank lines
-    text = "\n".join(line.strip() for line in text.splitlines())
+def clean_text(text, *args, **kwargs):
+    # Load replace_single_newlines from config
+    cfg = load_config()
+    replace_single_newlines = cfg.get("replace_single_newlines", False)
+    # Collapse all whitespace (excluding newlines) into single spaces per line and trim edges
+    lines = [re.sub(r"[^\S\n]+", " ", line).strip() for line in text.splitlines()]
+    text = "\n".join(lines)
     # Standardize paragraph breaks (multiple newlines become exactly two) and trim overall whitespace
     text = re.sub(r"\n{3,}", "\n\n", text).strip()
-    # Replace single newlines with spaces, but preserve double newlines
-    # text = re.sub(r"(?<!\n)\n(?!\n)", " ", text)
-    # Collapse multiple spaces and tabs into a single space
-    text = re.sub(r"[ \t]+", " ", text)
+    # Optionally replace single newlines with spaces, but preserve double newlines
+    if replace_single_newlines:
+        text = re.sub(r"(?<!\n)\n(?!\n)", " ", text)
     return text
 
 

abogen/voice_formulas.py

@@ -0,0 +1,57 @@
+import re
+from constants import VOICES_INTERNAL
+
+
+# Calls parsing and loads the voice to gpu or cpu
+def get_new_voice(pipeline, formula, use_gpu):
+    try:
+        weighted_voice = parse_voice_formula(pipeline, formula)
+        # device = "cuda" if use_gpu else "cpu"
+        # Setting the device "cuda" gives "Error occurred: split_with_sizes(): argument 'split_sizes' (position 2)"
+        # error when the device is gpu. So disabling this for now.
+        device = "cpu"
+        return weighted_voice.to(device)
+    except Exception as e:
+        raise ValueError(f"Failed to create voice: {str(e)}")
+
+
+# Parse the formula and get the combined voice tensor
+def parse_voice_formula(pipeline, formula):
+    if not formula.strip():
+        raise ValueError("Empty voice formula")
+
+    # Initialize the weighted sum
+    weighted_sum = None
+
+    total_weight = calculate_sum_from_formula(formula)
+
+    # Split the formula into terms
+    voices = formula.split("+")
+
+    for term in voices:
+        # Parse each term (format: "voice_name*0.333")
+        voice_name, weight = term.strip().split("*")
+        weight = float(weight.strip())
+        # normalize the weight
+        weight /= total_weight if total_weight > 0 else 1.0
+        voice_name = voice_name.strip()
+
+        # Get the voice tensor
+        if voice_name not in VOICES_INTERNAL:
+            raise ValueError(f"Unknown voice: {voice_name}")
+
+        voice_tensor = pipeline.load_single_voice(voice_name)
+
+        # Add to weighted sum
+        if weighted_sum is None:
+            weighted_sum = weight * voice_tensor
+        else:
+            weighted_sum += weight * voice_tensor
+
+    return weighted_sum
+
+
+def calculate_sum_from_formula(formula):
+    weights = re.findall(r"\* *([\d.]+)", formula)
+    total_sum = sum(float(weight) for weight in weights)
+    return total_sum

abogen/voice_profiles.py

@@ -0,0 +1,59 @@
+import os
+import json
+from utils import get_user_config_path
+
+
+def _get_profiles_path():
+    config_path = get_user_config_path()
+    config_dir = os.path.dirname(config_path)
+    return os.path.join(config_dir, "voice_profiles.json")
+
+
+def load_profiles():
+    """Load all voice profiles from JSON file."""
+    path = _get_profiles_path()
+    if os.path.exists(path):
+        try:
+            with open(path, "r", encoding="utf-8") as f:
+                data = json.load(f)
+                # always expect abogen_voice_profiles wrapper
+                if isinstance(data, dict) and "abogen_voice_profiles" in data:
+                    return data["abogen_voice_profiles"]
+                # fallback: treat as profiles dict
+                if isinstance(data, dict):
+                    return data
+        except Exception:
+            return {}
+    return {}
+
+
+def save_profiles(profiles):
+    """Save all voice profiles to JSON file."""
+    path = _get_profiles_path()
+    os.makedirs(os.path.dirname(path), exist_ok=True)
+    with open(path, "w", encoding="utf-8") as f:
+        # always save with abogen_voice_profiles wrapper
+        json.dump({"abogen_voice_profiles": profiles}, f, indent=2)
+
+
+def delete_profile(name):
+    """Remove a profile by name."""
+    profiles = load_profiles()
+    if name in profiles:
+        del profiles[name]
+        save_profiles(profiles)
+
+
+def duplicate_profile(src, dest):
+    """Duplicate an existing profile."""
+    profiles = load_profiles()
+    if src in profiles and dest:
+        profiles[dest] = profiles[src]
+        save_profiles(profiles)
+
+
+def export_profiles(export_path):
+    """Export all profiles to specified JSON file."""
+    profiles = load_profiles()
+    with open(export_path, "w", encoding="utf-8") as f:
+        json.dump({"abogen_voice_profiles": profiles}, f, indent=2)

demo/README.md

@@ -40,11 +40,6 @@ Run this FFmpeg command to create the tiny video:
 ffmpeg -loop 1 -framerate 24 -i bg.jpg -i audio.wav -vf "ass=your_subtitle_demo.ass" -c:v libvpx-vp9 -b:v 0 -crf 30 -c:a libopus -shortest demo.webm
 ```
 
-That's it! The magic happens because:
-- We use a single static background image instead of many frames
-- The subtitles are stored as text (vector data), not as pixels
-- VP9 video codec with Opus audio provides excellent compression
-
 ## For Higher Quality (But Larger) Video (.mp4)
 
 If you need better quality for distribution, use this command instead:

pyproject.toml

@@ -15,11 +15,15 @@ keywords = ["audiobook", "epub", "pdf", "text-to-speech", "subtitle", "tts", "ko
 dependencies = [
     "PyQt5>=5.15.11",
     "kokoro>=0.9.4",
-    "ebooklib>=0.18",
+    "ebooklib>=0.19",
     "beautifulsoup4>=4.13.4",
     "PyMuPDF>=1.25.5",
+    "platformdirs>=4.3.7",
     "soundfile>=0.13.1",
-    "pygame>=2.6.1"
+    "pygame>=2.6.1",
+    "charset_normalizer>=3.4.1",
+    "chardet>=5.2.0",
+    "static_ffmpeg>=2.13"
 ]
 
 classifiers = [
@@ -52,10 +56,9 @@ abogen-cli = "abogen.main:main"
 exclude = [
     "/.github",
     "/demo",
-    "/demo",
+    "/abogen/resources",
     "/abogen/assets/create_shortcuts.bat",
     "WINDOWS_INSTALL.bat",
-    
 ]
 
 [tool.hatch.build.targets.wheel]