Synthalingua

Note: The Synthalingua Wrapper code has been moved to a new repo here: https://github.com/cyberofficial/Synthalingua_Wrapper By using Synthalingua, you agree to use it responsibly and accept full responsibility for your actions. Let's keep it fun, safe, and positive for everyone!

• Real-time translation & transcription (stream, mic, file)
• Multilingual: Translate between dozens of languages
• Streaming & captions: HLS, YouTube, Twitch, and more
• Blocklist & repetition suppression: Auto-filter repeated or unwanted phrases
• Discord & web integration: Send results to Discord or view in browser
• Portable GUI version available

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Table of Contents

• About
• Documentation Wiki
• Quick Start
• Feature Highlights
• System Requirements
• Installation
• Command-Line Arguments
• Usage Examples
• Blocklist & Filtering
• Web & Discord Integration
• Troubleshooting
• Contributors
• Video Demonstration
• Support Synthalingua

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Documentation Wiki

For comprehensive guides and detailed documentation, visit the official Synthalingua Wiki:

https://github.com/cyberofficial/Synthalingua/wiki

The GitHub Wiki contains detailed guides for every feature, including setup, usage, troubleshooting, and advanced options. Always check the wiki for the latest documentation and tips!

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About Synthalingua

Synthalingua is an advanced, self-hosted tool that leverages the power of artificial intelligence to translate audio from various languages into English in near real time, offering the possibility of multilingual outputs. This innovative solution utilizes both GPU and CPU resources to handle input transcription and translation, ensuring optimized performance.

While currently in beta and not perfect, Synthalingua is actively being developed and will receive regular updates to further enhance its capabilities.

Synthalingua started as a very personal project for me. I was inspired by my love for VTubers, many of whom I could only understand through translated clips on YouTube. I wanted to experience their streams live, in real time, with the same depth and connection that native speakers enjoyed. While I could already watch live, it just wasn’t the same without fully understanding what was being said in the moment. That frustration turned into motivation, and I began working on a tool that could break through improve the experience.

What started as a small, personal endeavor quickly grew into something much larger than I could have imagined. The idea that language should never be a barrier to connection, whether in the VTuber community or beyond, really resonated with me. I wanted to create something that would allow anyone, anywhere, to fully experience the rich conversations, emotions, and stories that come from people speaking in their own native tongue - and that’s how Synthalingua was born.

Legal & Friendly Disclaimer

Hey there! Synthalingua is a fun and powerful tool for exploring languages, learning, and enjoying live translations. But just like any tool, it comes with a few important guidelines to keep things safe, legal, and friendly for everyone.

• Synthalingua is a tool, not a service. You run it on your own computer, and you are in control. It’s not a replacement for professional translators or interpreters.
• For fun, learning, and curiosity! Use Synthalingua to practice languages, understand foreign content, or experiment with AI audio. It’s great for hobbyists, students, and anyone curious about language tech.
• Not for official or critical use. Please don’t rely on Synthalingua for legal, medical, business, or other important communications. For anything serious, always consult a qualified human expert.
• Be kind and ethical. Don’t use Synthalingua to spread misinformation, harass others, or break the law. Respect the rules of any platform you use it with.
• Respect privacy and copyright. Only process audio or video you have the right to use. Don’t share or transcribe private conversations without permission.
• No warranty or liability. I built Synthalingua for the community, but I can’t take responsibility for how it’s used. You use it at your own risk.

👍 Examples of Good Use

• Translating a livestream for your own understanding
• Practicing a new language by listening to foreign media
• Making fun subtitles for a YouTube video you have rights to
• Learning how AI models handle different accents or languages

🚫 Please Don’t

• Use Synthalingua to translate confidential work meetings or private calls without consent
• Rely on it for medical, legal, or business decisions
• Use it to bypass paywalls, copyright, or platform rules
• Share or publish AI-generated translations as if they are 100% accurate or official

By using Synthalingua, you agree to use it responsibly and accept full responsibility for your actions. Let’s keep it fun, safe, and positive for everyone!

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Quick Start

1. Install Python 3.12 from here and Git
2. Install FFMPEG (guide)
3. (Optional) Install CUDA 12.8 for GPU acceleration if you plan to use GPU features
4. Run setup.bat (Windows) or setup.bash (Linux)
5. Edit and run the generated batch/bash file, or use the GUI portable version:

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Feature Highlights

• Suppress repeated/similar messages: Prevents spam from repeated or hallucinated phrases in all modes
• Auto blocklist: Frequently blocked phrases are auto-added to your blocklist file
• Flexible input: Microphone, HLS stream, or file
• Captions mode: Generate subtitles for any audio/video file
• Web server: View live subtitles in your browser
• Discord integration: Send results to a Discord channel
• Customizable: Blocklist, language, device, RAM, and more

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System Requirements

Requirement	Minimum	Moderate	Recommended	Best Performance
CPU	2 cores, 2.0 GHz+	4 cores, 3.0 GHz+	8 cores, 3.5 GHz+	16+ cores, 4.0 GHz+
RAM	4 GB	8 GB	16 GB	32+ GB
GPU (Nvidia)	2GB VRAM (Kepler/Maxwell, e.g. GTX 750 Ti)	4GB VRAM (Pascal, e.g. GTX 1050 Ti)	8GB VRAM (Turing/Ampere, e.g. RTX 2070/3070)	12GB+ VRAM (RTX 3080/3090, A6000, etc.)
GPU (AMD/Linux)	4GB VRAM (experimental)	8GB VRAM	12GB+ VRAM	16GB+ VRAM
OS	Windows 10+, Linux	Windows 10+, Linux	Windows 10+, Linux	Windows 10+, Linux
Storage	2 GB free	10 GB free	20 GB+ free	SSD/NVMe recommended

Supported GPUs:

• Nvidia: Most CUDA-capable cards (Kepler, Maxwell, Pascal, Turing, Ampere, Ada; e.g. GTX 750 Ti, 1050 Ti, 1660, RTX 2060/2070/2080/3060/3070/3080/3090/40xx, A6000, etc.)
• AMD: ROCm-compatible cards (Linux only, experimental)
• CPU: Supported (slower, but works for small models)

Notes:

• Nvidia GPU with CUDA is strongly recommended for best performance.
• AMD GPU support is experimental and Linux-only (see ROCm docs).
• CPU-only mode is available for testing or low-resource systems.
• Microphone is optional (use --stream for HLS input).
• For a full list of supported Nvidia GPUs, see the Official Nvidia List or Simple Nvidia List.

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Installation

1. Install Python 3.12
2. Install Git
3. Install FFMPEG (guide)
4. (Optional) Install CUDA 12.8 for GPU if you plan to use GPU features
5. Run setup.bat (Windows) or setup.bash (Linux)
6. Edit and run the generated batch/bash file, or use the GUI

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Command-Line Arguments

General

Flag	Description
--about	Show app info
--updatebranch	Update branch (master/dev-testing/bleeding-under-work/disable)
--no_log	Only show last line of output
--keep_temp	Keep temp audio files
--save_transcript	Save transcript to file
--save_folder	Set transcript save folder

Model & Device

Flag	Description
--ram	Model size (1gb, 2gb, 3gb, 6gb, 11gb-v2, 11gb-v3)
--ramforce	Force RAM/VRAM model
--fp16	Enable FP16 mode
--device	Device: (auto/cpu/cuda/intel-igpu/intel-dgpu/intel-npu)
--cuda_device	CUDA device index
--model_dir	Model directory
--model_source	Source of the model (Whisper, FasterWhisper, OpenVINO)
--compute_type	Quantization of the model

Input & Microphone

Flag	Description
--microphone_enabled	Enable microphone input
--list_microphones	List microphones
--set_microphone	Set mic by name or index
--energy_threshold	Mic energy threshold
--mic_calibration_time	Mic calibration time
--record_timeout	Recording chunk length
--phrase_timeout	Silence before new line

Streaming & File

Flag	Description
--selectsource	Select the stream audio source (interactive.)
--stream	HLS stream input
--stream_language	Stream language
--stream_translate	Enable stream translation
--stream_transcribe [language]	Enable stream transcription with optional target language (e.g., --stream_transcribe English)
--stream_original_text	Show original stream text
--stream_chunks	Stream chunk size
--paddedaudio	Number of chunks to overlap from previous batch for better context (works with both --stream and microphone input)
--auto_hls	Auto HLS chunk tuning
--cookies	Cookies file (supports absolute paths, current dir, or cookies/ folder)
--remote_hls_password_id	Webserver password ID
--remote_hls_password	Webserver password for

Language & Translation

Flag	Description
--language	Source language
--target_language	Target language
--translate	Enable translation
--transcribe	Transcribe to target language
--auto_language_lock	Auto language lock
--condition_on_previous_text	Suppress repeated/similar messages

Output, Captions, and Filtering

Flag	Description
--makecaptions	Captions mode. Use --makecaptions compare to generate captions with all RAM models
--subtype	Process video with subtitles after generation. 'burn' overlays subtitles permanently onto video. 'embed' adds subtitle track to video container. Only works with --makecaptions and video files.
--substyle	Customize burned subtitle appearance (only with --subtype burn). Format: 'font,size,color' in any order. Font files go in fonts/ folder. Use --substyle help for examples.
--word_timestamps	Enable word-level timestamps in subtitle output (sub_gen only). May make subtitle generation slower as it requires more processing power. If you notice slowdowns, remove this flag next time. Has no effect in microphone or HLS/stream modes.
--isolate_vocals	Attempt to isolate vocals from the input audio before generating subtitles (sub_gen only). Requires the demucs package.
--demucs_model	Demucs model to use for vocal isolation. Choices: htdemucs (default), htdemucs_ft, htdemucs_6s, hdemucs_mmi, mdx, mdx_extra, mdx_q, mdx_extra_q, hdemucs, demucs. Only used when --isolate_vocals is enabled.
--silent_detect	Skip processing silent audio chunks during caption generation (sub_gen only). Improves processing speed for files with long silent periods. Highly recommended with --isolate_vocals for maximum efficiency. Note: Only works with --makecaptions - not supported for HLS/streaming or microphone modes.
--silent_threshold	dB threshold for silence detection (default: -35.0). Lower values (e.g., -45.0) detect quieter speech like whispers. Higher values (e.g., -25.0) only detect louder speech. Only used with --silent_detect.
--silent_duration	Minimum duration in seconds for a region to be considered silence (default: 0.5). Higher values (e.g., 2.0) treat brief pauses as speech. Lower values (e.g., 0.1) detect shorter silent periods. Only used with --silent_detect.
--print_srt_to_console	Print the final generated SRT subtitles to the console after file creation (captions mode only).
--file_input	Input file for captions
--file_output	Output folder for captions
--file_output_name	Output file name
--ignorelist	Blocklist file (words/phrases)
--auto_blocklist	Auto-add frequently blocked phrases to blocklist
--debug	Print debug info for blocked/suppressed messages

Print SRT to Console

The --print_srt_to_console flag prints the final, fully combined SRT subtitles to the console after the SRT file is created (captions mode only). This is useful for quickly viewing the generated subtitles without opening the SRT file manually. It only prints the final combined SRT (not per-segment SRTs) and works with --makecaptions.

Example:

python synthalingua.py --makecaptions --file_input="C:/path/video.mp4" --file_output="C:/output" --file_output_name="MyCaptionsFile" --print_srt_to_console

This will save the SRT file as usual and also print its contents to the console at the end of processing.

Web & Discord

Flag	Description
--portnumber	Web server port
--discord_webhook	Discord webhook URL

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Usage Examples

• Stream translation:

  python synthalingua.py --ram 11gb-v3 --stream_translate --stream_language Japanese --stream https://www.twitch.tv/somestreamerhere

• Microphone translation:

  python synthalingua.py --ram 6gb --translate --language ja --discord_webhook "https://discord.com/api/webhooks/1234567890/1234567890" --energy_threshold 300

• Captions mode:

  python synthalingua.py --ram 11gb-v3 --makecaptions --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With word-level timestamps (may be slower):
  python synthalingua.py --ram 11gb-v3 --makecaptions --word_timestamps --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With vocal isolation (requires demucs):
  python synthalingua.py --ram 11gb-v3 --makecaptions --isolate_vocals --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With vocal isolation using specific model (skip interactive prompt):
  python synthalingua.py --ram 11gb-v3 --makecaptions --isolate_vocals --demucs_model htdemucs_ft --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With silence detection (faster processing for long silent periods):
  python synthalingua.py --ram 11gb-v3 --makecaptions --silent_detect --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With custom silence threshold for quiet speech (e.g., whispers):
  python synthalingua.py --ram 11gb-v3 --makecaptions --silent_detect --silent_threshold -45.0 --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With custom duration to ignore brief pauses (e.g., 2s minimum):
  python synthalingua.py --ram 11gb-v3 --makecaptions --silent_detect --silent_duration 2.0 --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # RECOMMENDED: Vocal isolation + silence detection (maximum efficiency and quality):
  python synthalingua.py --ram 11gb-v3 --makecaptions --isolate_vocals --silent_detect --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda

• Captions compare mode (all models):

  python synthalingua.py --makecaptions compare --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With word-level timestamps (may be slower):
  python synthalingua.py --makecaptions compare --word_timestamps --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # With vocal isolation (requires demucs):
  python synthalingua.py --makecaptions compare --isolate_vocals --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # RECOMMENDED: Vocal isolation + silence detection (maximum efficiency and quality):
  python synthalingua.py --makecaptions compare --isolate_vocals --silent_detect --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda

• Video subtitle processing (burn subtitles permanently):

  python synthalingua.py --makecaptions --subtype burn --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda

• Video subtitle processing (embed toggleable subtitles):

  python synthalingua.py --makecaptions --subtype embed --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda

• Custom styled burned subtitles:

  # Large yellow text with custom font
  python synthalingua.py --makecaptions --subtype burn --substyle "FiraSans-Bold.otf,28,yellow" --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # System font with size and color
  python synthalingua.py --makecaptions --subtype burn --substyle "22,cyan" --file_input="C:\Users\username\Downloads\file.mp4" --file_output="C:\Users\username\Downloads" --file_output_name="outputname" --language Japanese --device cuda
  # Get help and see available fonts
  python synthalingua.py --substyle help

• Set microphone by name or index:

  python synthalingua.py --set_microphone "Microphone (Realtek USB2.0 Audi)"
  python synthalingua.py --set_microphone 4

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Caption Generation Optimization

Advanced Caption Features

For the best caption generation experience, Synthalingua offers several advanced features that can be combined:

Silent Detection (--silent_detect)

• What it does: Intelligently skips silent regions in audio files
• Benefits: Faster processing, reduced resource usage, better transcription quality
• Best for: Podcasts, lectures, videos with long pauses or intro/outro music
• Usage: Only works with --makecaptions (caption generation mode)
• Not supported: HLS/streaming modes or microphone input
• Customizable settings:
  • Threshold (--silent_threshold): Controls volume sensitivity
    • Default: -35.0dB (good for normal speech)
    • Quiet speech/whispers: -45.0dB or lower (more sensitive)
    • Loud speech only: -25.0dB or higher (less sensitive)
  • Duration (--silent_duration): Controls minimum silence length
    • Default: 0.5s (brief pauses treated as speech)
    • Ignore short pauses: 2.0s+ (only long silences count)
    • Detect quick breaks: 0.1s (very sensitive to gaps)

Vocal Isolation (--isolate_vocals)

• What it does: Separates vocals from background music/noise using AI (requires demucs)
• Benefits: Cleaner transcription, better accuracy in noisy environments
• Best for: Music videos, podcasts with background music, noisy recordings
• Requires: pip install demucs or included in some distributions

** Maximum Efficiency Combo (RECOMMENDED)**

Combine both features for optimal results:

python synthalingua.py --makecaptions --isolate_vocals --silent_detect --file_input="your_file.mp4"

Why this combination works so well:

1. Vocal isolation removes background noise/music, creating cleaner audio
2. Silent detection analyzes the cleaned audio for more accurate silence detection
3. Result: Only speech regions from isolated vocals are processed
4. Benefits:
   • Fastest processing (skips silence and noise)
   • Highest accuracy (clean vocal-only audio)
   • Resource efficient (processes less audio overall)
   • Natural boundaries (respects speech patterns, no mid-word cuts)

Processing Workflow

1. Input: Original audio/video file
2. Vocal Isolation: Extracts clean vocals (if --isolate_vocals)
3. Silence Detection: Finds speech regions in vocal track (if --silent_detect)
4. Transcription: Processes only speech regions with natural boundaries
5. Output: High-quality SRT captions with perfect timestamps

** Pro Tips**

• Use --makecaptions compare with both flags to test all models efficiently
• Silent detection works on any audio, but is most effective with vocal isolation
• Both features maintain perfect timestamp accuracy in final SRT files
• Vocal isolation creates temporary files in temp/audio/ directory

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Blocklist & Filtering

• Use --ignorelist to load a blocklist file (one word/phrase per line)
• Suppression: With --condition_on_previous_text, repeated or highly similar messages are automatically suppressed in all modes
• Auto blocklist: With --auto_blocklist and --ignorelist, phrases blocked 3+ times in the last 10 are auto-added to your blocklist
• Debug: Use --debug to print info about blocked/suppressed messages
• Blocklist and suppression logic applies to all output (console, Discord, web)

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Web & Discord Integration

• Discord: Use --discord_webhook to send results to Discord (long messages are split, rate limits handled)
• Web server: Use --portnumber to launch a local Flask server and view subtitles in your browser

Accessing the Web Server

Once you've launched Synthalingua with the --portnumber parameter:

1. Open your web browser and navigate to http://localhost:[PORT] (replace [PORT] with the port number you specified)
2. Example: http://localhost:8080 if you used --portnumber 8080
3. For accessing from other devices on your network, use your computer's IP address: http://[YOUR_IP]:[PORT]

Example usage:

# Start Synthalingua with a web server on port 8080
python synthalingua.py --ram 6gb --translate --language ja --portnumber 8080

# For remote HLS password protection
python synthalingua.py --ram 6gb --translate --portnumber 8080 --remote_hls_password_id "user" --remote_hls_password "yourpassword"

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Troubleshooting

• Python not recognized: Add Python to PATH, restart, check version (should be 3.12)
• No module named 'transformers': Run pip install transformers in the correct Python environment
• Git not recognized: Add Git to PATH, restart
• CUDA not available: Install CUDA 12.8 (Nvidia only), or use CPU mode
• Audio source errors: Make sure a microphone or stream is set up
• For detailed troubleshooting: See the Troubleshooting Guide in the information folder
• Other issues: See GitHub Issues

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Contributors

• @DaniruKun - https://watsonindustries.live
• @Expletive - https://evitelpxe.neocities.org
• @Adenser
• @YuumiPie

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Video Demonstration

Command line arguments used: --ram 6gb --record_timeout 2 --language ja --energy_threshold 500

Command line arguments used: --ram 11gb-v2 --record_timeout 5 --language id --energy_threshold 500

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Support Synthalingua

If Synthalingua has made a difference in your life and you find yourself using it regularly, I would be truly grateful if you considered supporting its continued development. 😁 Running a GPU at full power day in and day out requires a lot of resources, and the cost of electricity and maintenance adds up over time. Any contribution, no matter how small, would help tremendously in keeping this project going strong and ensuring that I can continue to improve and expand it for everyone.

Your support would not just help cover the costs of running and maintaining Synthalingua, it would also be a vote of confidence in this vision — a world where language doesn’t stand in the way of connection and understanding. I believe that no one should feel left out of a new experience just because it’s in a different language. Every conversation, every voice, deserves to be understood and appreciated. If you can not support through monetary means, just sharing the application would also be a great benefit to those who want the same experience I wanted but don't know where to begin.

Synthalingua will always remain free, because I want this tool to be available to anyone who needs it, regardless of their financial situation. But if it has enriched your experience, opened up new possibilities for you, or simply made your world a little bigger, your support would mean the world to me. It helps keep this project alive and ensures that others can also benefit from this tool and the vision behind it.

Thank you for being part of this journey. Your belief in Synthalingua and its mission is what drives me to keep going, and I’m incredibly grateful for every one of you who uses and believes in this project. Together, we can help build a future where communication knows no boundaries, and language is a bridge rather than a barrier.

Support via:

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Credits

Developed proudly in PyCharm IDE from JetBrains

JetBrains kindly provided an OSS license for this project, greatly improving development productivity. Learn more

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More

• Wiki
• Official Nvidia List
• Simple Nvidia List
• FFMPEG Install Guide

Word-level Timestamps

The --word_timestamps flag enables word-level timestamps in subtitle output (sub_gen/captions mode only). This provides more precise alignment but may make subtitle generation a bit slower as it requires more processing power. If you notice any unusual slowdowns, try removing the flag next time you run this command.

Note: This flag has no effect in microphone or HLS/stream modes, and will show a warning if used there.

Vocal Isolation

The --isolate_vocals flag attempts to isolate vocals from the input audio before generating subtitles (sub_gen/captions mode only). This can improve subtitle accuracy for music or noisy audio, but may take additional time and requires the demucs package. If demucs is not installed, a warning will be shown.

Demucs Model Selection:

• By default, the program will prompt you to select which Demucs model to use for vocal isolation
• You can skip the prompt by using --demucs_model to specify the model directly
• Available models:
  • htdemucs (default): Latest Hybrid Transformer model
  • htdemucs_ft: Fine-tuned version for better quality (slower)
  • htdemucs_6s: 6-source separation (includes piano/guitar)
  • hdemucs_mmi: Hybrid v3 trained on expanded dataset
  • mdx: Frequency-domain model, MDX winner
  • mdx_extra: Enhanced MDX with extra training data
  • mdx_q: Quantized MDX (faster, smaller)
  • mdx_extra_q: Quantized MDX Extra (faster, smaller)
  • hdemucs: Original Hybrid Demucs v3
  • demucs: Original time-domain Demucs

Examples:

# Interactive model selection (default behavior)
python synthalingua.py --makecaptions --isolate_vocals --file_input="video.mp4"

# Specify model directly (no prompt)
python synthalingua.py --makecaptions --isolate_vocals --demucs_model htdemucs_ft --file_input="video.mp4"

# For best quality (slower)
python synthalingua.py --makecaptions --isolate_vocals --demucs_model htdemucs_ft --file_input="video.mp4"

# For fastest processing
python synthalingua.py --makecaptions --isolate_vocals --demucs_model mdx_q --file_input="video.mp4"

Note: This flag has no effect in microphone or HLS/stream modes.