You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
195 lines
9.8 KiB
195 lines
9.8 KiB
10 months ago
|
Metadata-Version: 2.1
|
||
|
|
Name: ffsubsync
|
||
|
|
Version: 0.4.25
|
||
|
|
Summary: Language-agnostic synchronization of subtitles with video.
|
||
|
|
Home-page: https://github.com/smacke/ffsubsync
|
||
|
|
Author: Stephen Macke
|
||
|
|
Author-email: stephen.macke@gmail.com
|
||
|
|
License: MIT
|
||
|
|
Classifier: Development Status :: 3 - Alpha
|
||
|
|
Classifier: Intended Audience :: End Users/Desktop
|
||
|
|
Classifier: License :: OSI Approved :: MIT License
|
||
|
|
Classifier: Natural Language :: English
|
||
|
|
Classifier: Programming Language :: Python :: 3.6
|
||
|
|
Classifier: Programming Language :: Python :: 3.7
|
||
|
|
Classifier: Programming Language :: Python :: 3.8
|
||
|
|
Classifier: Programming Language :: Python :: 3.9
|
||
|
|
Classifier: Programming Language :: Python :: 3.10
|
||
|
|
Classifier: Programming Language :: Python :: 3.11
|
||
|
|
Classifier: Topic :: Multimedia :: Sound/Audio :: Analysis
|
||
|
|
Classifier: Topic :: Multimedia :: Sound/Audio :: Speech
|
||
|
|
Description-Content-Type: text/markdown
|
||
|
|
License-File: LICENSE
|
||
|
|
Requires-Dist: auditok (==0.1.5)
|
||
|
|
Requires-Dist: charset-normalizer
|
||
|
|
Requires-Dist: faust-cchardet
|
||
|
|
Requires-Dist: ffmpeg-python
|
||
|
|
Requires-Dist: future (>=0.18.2)
|
||
|
|
Requires-Dist: numpy (>=1.12.0)
|
||
|
|
Requires-Dist: rich
|
||
|
|
Requires-Dist: six
|
||
|
|
Requires-Dist: srt (>=3.0.0)
|
||
|
|
Requires-Dist: tqdm
|
||
|
|
Requires-Dist: typing-extensions
|
||
|
|
Requires-Dist: webrtcvad ; platform_system != "Windows"
|
||
|
|
Requires-Dist: webrtcvad-wheels ; platform_system == "Windows"
|
||
|
|
Requires-Dist: pysubs2 ; python_version < "3.7"
|
||
|
|
Requires-Dist: chardet ; python_version >= "3.7"
|
||
|
|
Requires-Dist: pysubs2 (>=1.2.0) ; python_version >= "3.7"
|
||
|
|
|
||
|
|
FFsubsync
|
||
|
|
=======
|
||
|
|
|
||
|
|
[](https://github.com/smacke/ffsubsync/actions)
|
||
|
|
[](https://github.com/vshymanskyy/StandWithUkraine/blob/main/docs/README.md)
|
||
|
|
[](http://mypy-lang.org/)
|
||
|
|
[](https://github.com/psf/black)
|
||
|
|
[](https://opensource.org/licenses/MIT)
|
||
|
|
[](https://pypi.org/project/ffsubsync)
|
||
|
|
[](https://ffsubsync.readthedocs.io/en/latest/?badge=latest)
|
||
|
|
[](https://pypi.org/project/ffsubsync)
|
||
|
|
|
||
|
|
|
||
|
|
Language-agnostic automatic synchronization of subtitles with video, so that
|
||
|
|
subtitles are aligned to the correct starting point within the video.
|
||
|
|
|
||
|
|
Turn this: | Into this:
|
||
|
|
:-------------------------------:|:-------------------------:
|
||
|
|
 | 
|
||
|
|
|
||
|
|
Helping Development
|
||
|
|
-------------------
|
||
|
|
Please consider [supporting Ukraine](https://github.com/vshymanskyy/StandWithUkraine/blob/main/docs/README.md)
|
||
|
|
rather than donating directly to this project. That said, at the request of
|
||
|
|
some, you can now help cover my coffee expenses using the Github Sponsors
|
||
|
|
button at the top, or using the below Paypal Donate button:
|
||
|
|
|
||
|
|
[](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=XJC5ANLMYECJE)
|
||
|
|
|
||
|
|
Install
|
||
|
|
-------
|
||
|
|
First, make sure ffmpeg is installed. On MacOS, this looks like:
|
||
|
|
~~~
|
||
|
|
brew install ffmpeg
|
||
|
|
~~~
|
||
|
|
(Windows users: make sure `ffmpeg` is on your path and can be referenced
|
||
|
|
from the command line!)
|
||
|
|
|
||
|
|
Next, grab the package (compatible with Python >= 3.6):
|
||
|
|
~~~
|
||
|
|
pip install ffsubsync
|
||
|
|
~~~
|
||
|
|
If you want to live dangerously, you can grab the latest version as follows:
|
||
|
|
~~~
|
||
|
|
pip install git+https://github.com/smacke/ffsubsync@latest
|
||
|
|
~~~
|
||
|
|
|
||
|
|
Usage
|
||
|
|
-----
|
||
|
|
`ffs`, `subsync` and `ffsubsync` all work as entrypoints:
|
||
|
|
~~~
|
||
|
|
ffs video.mp4 -i unsynchronized.srt -o synchronized.srt
|
||
|
|
~~~
|
||
|
|
|
||
|
|
There may be occasions where you have a correctly synchronized srt file in a
|
||
|
|
language you are unfamiliar with, as well as an unsynchronized srt file in your
|
||
|
|
native language. In this case, you can use the correctly synchronized srt file
|
||
|
|
directly as a reference for synchronization, instead of using the video as the
|
||
|
|
reference:
|
||
|
|
|
||
|
|
~~~
|
||
|
|
ffsubsync reference.srt -i unsynchronized.srt -o synchronized.srt
|
||
|
|
~~~
|
||
|
|
|
||
|
|
`ffsubsync` uses the file extension to decide whether to perform voice activity
|
||
|
|
detection on the audio or to directly extract speech from an srt file.
|
||
|
|
|
||
|
|
Sync Issues
|
||
|
|
-----------
|
||
|
|
If the sync fails, the following recourses are available:
|
||
|
|
- Try to sync assuming identical video / subtitle framerates by passing
|
||
|
|
`--no-fix-framerate`;
|
||
|
|
- Try passing `--gss` to use [golden-section search](https://en.wikipedia.org/wiki/Golden-section_search)
|
||
|
|
to find the optimal ratio between video and subtitle framerates (by default,
|
||
|
|
only a few common ratios are evaluated);
|
||
|
|
- Try a value of `--max-offset-seconds` greater than the default of 60, in the
|
||
|
|
event that the subtitles are out of sync by more than 60 seconds (empirically
|
||
|
|
unlikely in practice, but possible).
|
||
|
|
- Try `--vad=auditok` since [auditok](https://github.com/amsehili/auditok) can
|
||
|
|
sometimes work better in the case of low-quality audio than WebRTC's VAD.
|
||
|
|
Auditok does not specifically detect voice, but instead detects all audio;
|
||
|
|
this property can yield suboptimal syncing behavior when a proper VAD can
|
||
|
|
work well, but can be effective in some cases.
|
||
|
|
|
||
|
|
If the sync still fails, consider trying one of the following similar tools:
|
||
|
|
- [sc0ty/subsync](https://github.com/sc0ty/subsync): does speech-to-text and looks for matching word morphemes
|
||
|
|
- [kaegi/alass](https://github.com/kaegi/alass): rust-based subtitle synchronizer with a fancy dynamic programming algorithm
|
||
|
|
- [tympanix/subsync](https://github.com/tympanix/subsync): neural net based approach that optimizes directly for alignment when performing speech detection
|
||
|
|
- [oseiskar/autosubsync](https://github.com/oseiskar/autosubsync): performs speech detection with bespoke spectrogram + logistic regression
|
||
|
|
- [pums974/srtsync](https://github.com/pums974/srtsync): similar approach to ffsubsync (WebRTC's VAD + FFT to maximize signal cross correlation)
|
||
|
|
|
||
|
|
Speed
|
||
|
|
-----
|
||
|
|
`ffsubsync` usually finishes in 20 to 30 seconds, depending on the length of
|
||
|
|
the video. The most expensive step is actually extraction of raw audio. If you
|
||
|
|
already have a correctly synchronized "reference" srt file (in which case audio
|
||
|
|
extraction can be skipped), `ffsubsync` typically runs in less than a second.
|
||
|
|
|
||
|
|
How It Works
|
||
|
|
------------
|
||
|
|
The synchronization algorithm operates in 3 steps:
|
||
|
|
1. Discretize both the video file's audio stream and the subtitles into 10ms
|
||
|
|
windows.
|
||
|
|
2. For each 10ms window, determine whether that window contains speech. This
|
||
|
|
is trivial to do for subtitles (we just determine whether any subtitle is
|
||
|
|
"on" during each time window); for the audio stream, use an off-the-shelf
|
||
|
|
voice activity detector (VAD) like
|
||
|
|
the one built into [webrtc](https://webrtc.org/).
|
||
|
|
3. Now we have two binary strings: one for the subtitles, and one for the
|
||
|
|
video. Try to align these strings by matching 0's with 0's and 1's with
|
||
|
|
1's. We score these alignments as (# video 1's matched w/ subtitle 1's) - (#
|
||
|
|
video 1's matched with subtitle 0's).
|
||
|
|
|
||
|
|
The best-scoring alignment from step 3 determines how to offset the subtitles
|
||
|
|
in time so that they are properly synced with the video. Because the binary
|
||
|
|
strings are fairly long (millions of digits for video longer than an hour), the
|
||
|
|
naive O(n^2) strategy for scoring all alignments is unacceptable. Instead, we
|
||
|
|
use the fact that "scoring all alignments" is a convolution operation and can
|
||
|
|
be implemented with the Fast Fourier Transform (FFT), bringing the complexity
|
||
|
|
down to O(n log n).
|
||
|
|
|
||
|
|
Limitations
|
||
|
|
-----------
|
||
|
|
In most cases, inconsistencies between video and subtitles occur when starting
|
||
|
|
or ending segments present in video are not present in subtitles, or vice versa.
|
||
|
|
This can occur, for example, when a TV episode recap in the subtitles was pruned
|
||
|
|
from video. FFsubsync typically works well in these cases, and in my experience
|
||
|
|
this covers >95% of use cases. Handling breaks and splits outside of the beginning
|
||
|
|
and ending segments is left to future work (see below).
|
||
|
|
|
||
|
|
Future Work
|
||
|
|
-----------
|
||
|
|
Besides general stability and usability improvements, one line
|
||
|
|
of work aims to extend the synchronization algorithm to handle splits
|
||
|
|
/ breaks in the middle of video not present in subtitles (or vice versa).
|
||
|
|
Developing a robust solution will take some time (assuming one is possible).
|
||
|
|
See [#10](https://github.com/smacke/ffsubsync/issues/10) for more details.
|
||
|
|
|
||
|
|
History
|
||
|
|
-------
|
||
|
|
The implementation for this project was started during HackIllinois 2019, for
|
||
|
|
which it received an **_Honorable Mention_** (ranked in the top 5 projects,
|
||
|
|
excluding projects that won company-specific prizes).
|
||
|
|
|
||
|
|
Credits
|
||
|
|
-------
|
||
|
|
This project would not be possible without the following libraries:
|
||
|
|
- [ffmpeg](https://www.ffmpeg.org/) and the [ffmpeg-python](https://github.com/kkroening/ffmpeg-python) wrapper, for extracting raw audio from video
|
||
|
|
- VAD from [webrtc](https://webrtc.org/) and the [py-webrtcvad](https://github.com/wiseman/py-webrtcvad) wrapper, for speech detection
|
||
|
|
- [srt](https://pypi.org/project/srt/) for operating on [SRT files](https://en.wikipedia.org/wiki/SubRip#SubRip_text_file_format)
|
||
|
|
- [numpy](http://www.numpy.org/) and, indirectly, [FFTPACK](https://www.netlib.org/fftpack/), which powers the FFT-based algorithm for fast scoring of alignments between subtitles (or subtitles and video)
|
||
|
|
- Other excellent Python libraries like [argparse](https://docs.python.org/3/library/argparse.html), [rich](https://github.com/willmcgugan/rich), and [tqdm](https://tqdm.github.io/), not related to the core functionality, but which enable much better experiences for developers and users.
|
||
|
|
|
||
|
|
# License
|
||
|
|
Code in this project is [MIT licensed](https://opensource.org/licenses/MIT).
|