subaligner

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Supported Formats

Subtitle: SubRip, TTML, WebVTT, (Advanced) SubStation Alpha, MicroDVD, MPL2, TMP, EBU STL, SAMI, SCC and SBV.

Video/Audio: MP4, WebM, Ogg, 3GP, FLV, MOV, Matroska, MPEG TS, WAV, MP3, AAC, FLAC, etc.

Dependencies

Required by basic: FFmpeg

$ apt-get install ffmpeg

or

$ brew install ffmpeg

Basic Installation

$ pip install -U pip
$ pip install subaligner

Installation with Optional Packages Supporting Additional Features

# Install dependencies for enabling translation

$ pip install 'subaligner[translation]'

# Install dependencies for enabling forced alignment

$ pip install 'subaligner[stretch]'

# Install dependencies for setting up the development environment

$ pip install 'subaligner[dev]'

Note that both subaligner[stretch] and subaligner[dev] require additional dependencies to be pre-installed:

$ apt-get install espeak libespeak1 libespeak-dev espeak-data

or

$ brew install espeak

To install all supported features:

$ pip install 'subaligner[harmony]'

Alternative Installations

# Install via pipx
$ pip install -U pip pipx
$ pipx install subaligner

or

# Install from GitHub via Pipenv
$ pipenv install subaligner
$ pipenv install 'subaligner[stretch]'
$ pipenv install 'subaligner[dev]'

or

# Install from source

$ git clone [email protected]:baxtree/subaligner.git
$ cd subaligner
$ python setup.py install

or

# Use dockerised installation

$ docker run -v `pwd`:`pwd` -w `pwd` -it baxtree/subaligner bash

For users on Windows 10: Docker Desktop is the only option at present. Assuming your media assets are stored under d:\media, open built-in command prompt, PowerShell, or Windows Terminal and run:

docker pull baxtree/subaligner
docker run -v "/d/media":/media -w "/media" -it baxtree/subaligner bash

Usage

# Single-stage alignment (high-level shift with lower latency)

$ subaligner_1pass -v video.mp4 -s subtitle.srt
$ subaligner_1pass -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt

# Dual-stage alignment (low-level shift with higher latency)

$ subaligner_2pass -v video.mp4 -s subtitle.srt
$ subaligner_2pass -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt

or

# Pass in single-stage or dual-stage as the alignment mode

$ subaligner -m single -v video.mp4 -s subtitle.srt
$ subaligner -m dual -v video.mp4 -s subtitle.srt
$ subaligner -m single -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt
$ subaligner -m dual -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt

# Alignment on segmented plain texts (double newlines as the delimiter)

$ subaligner -m script -v test.mp4 -s subtitle.txt -o subtitle_aligned.srt
$ subaligner -m script -v https://example.com/video.mp4 -s https://example.com/subtitle.txt -o subtitle_aligned.srt

# Alignment on multiple subtitles against the single media file

$ subaligner -m script -v test.mp4 -s subtitle_lang_1.txt -s subtitle_lang_2.txt
$ subaligner -m script -v test.mp4 -s subtitle_lang_1.txt subtitle_lang_2.txt

# Alignment on embedded subtitles

$ subaligner -m single -v video.mkv -s embedded:stream_index=0 -o subtitle_aligned.srt
$ subaligner -m dual -v video.mkv -s embedded:stream_index=0 -o subtitle_aligned.srt

# Translative alignment with the ISO 639-3 language code pair (src,tgt)

$ subaligner_1pass --languages
$ subaligner_1pass -v video.mp4 -s subtitle.srt -t src,tgt
$ subaligner_2pass --languages
$ subaligner_2pass -v video.mp4 -s subtitle.srt -t src,tgt
$ subaligner --languages
$ subaligner -m single -v video.mp4 -s subtitle.srt -t src,tgt
$ subaligner -m dual -v video.mp4 -s subtitle.srt -t src,tgt
$ subaligner -m script -v test.mp4 -s subtitle.txt -o subtitle_aligned.srt -t src,tgt

# Shift subtitle manually by offset in seconds

$ subaligner -m shift --subtitle_path subtitle.srt -os 5.5
$ subaligner -m shift --subtitle_path subtitle.srt -os -5.5 -o subtitle_shifted.srt

# Run batch alignment against directories

$ subaligner_batch -m single -vd videos/ -sd subtitles/ -od aligned_subtitles/
$ subaligner_batch -m dual -vd videos/ -sd subtitles/ -od aligned_subtitles/
$ subaligner_batch -m dual -vd videos/ -sd subtitles/ -od aligned_subtitles/ -of ttml

# Run alignments with pipx

$ pipx run subaligner -m single -v video.mp4 -s subtitle.srt
$ pipx run subaligner -m dual -v video.mp4 -s subtitle.srt

# Run the module as a script
$ python -m subaligner -m single -v video.mp4 -s subtitle.srt
$ python -m subaligner -m dual -v video.mp4 -s subtitle.srt
$ python -m subaligner.subaligner_1pass -v video.mp4 -s subtitle.srt
$ python -m subaligner.subaligner_2pass -v video.mp4 -s subtitle.srt

# Run alignments with the docker image

$ docker pull baxtree/subaligner
$ docker run -v `pwd`:`pwd` -w `pwd` -it baxtree/subaligner subaligner_1pass -v video.mp4 -s subtitle.srt
$ docker run -v `pwd`:`pwd` -w `pwd` -it baxtree/subaligner subaligner_2pass -v video.mp4 -s subtitle.srt
$ docker run -it baxtree/subaligner subaligner_1pass -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt
$ docker run -it baxtree/subaligner subaligner_2pass -v https://example.com/video.mp4 -s https://example.com/subtitle.srt -o subtitle_aligned.srt

The aligned subtitle will be saved at subtitle_aligned.srt. For details on CLI, run subaligner_1pass -h, subaligner_2pass -h or subaligner -h. Additional utilities can be used after consulting subaligner_batch -h, subaligner_convert -h, subaligner_train -h and subaligner_tune -h.

Advanced Usage

You can train a new model with your own audiovisual files and subtitle files:

$ subaligner_train -vd VIDEO_DIRECTORY -sd SUBTITLE_DIRECTORY -tod TRAINING_OUTPUT_DIRECTORY

Then you can apply it to your subtitle synchronisation with the aforementioned commands. For more details on how to train and tune your own model, please refer to Subaligner Docs.

Anatomy

Subtitles can be out of sync with their companion audiovisual media files for a variety of causes including latency introduced by Speech-To-Text on live streams or calibration and rectification involving human intervention during post-production.

A model has been trained with synchronised video and subtitle pairs and later used for predicating shifting offsets and directions under the guidance of a dual-stage aligning approach.

First Stage (Global Alignment):

Second Stage (Parallelised Individual Alignment):

Acknowledgement

This tool wouldn't be possible without the following packages: librosa tensorflow scikit-learn pycaption pysrt pysubs2 aeneas transformers.

Thanks to Alan Robinson and Nigel Megitt for their invaluable feedback.