Yle live stream subtitle downloader

A hacky little companion application for yle-dl, which currently cannot download subtitles for live streams due to an ffmpeg bug (see yle-dl bug 295). This program is meant for Yle live streams and may or may not work on other videos — just use yle-dl for them.

Note: Downloaded subtitles will be out of sync with the video. This is because they are downloaded separately with no guarantee of exact same start time and no timestamps stored in the video file. Subtitled must be synchronized manually, either with a subtitle resync tool or by using a video player that supports subtitle timing adjustment.

This project is not actively maintained. It's just something I threw together when I realized subtitles were missing (and after I gave up on digging around ffmpeg internals). I hope it won't be needed for long.

Installation

1. install pipx
2. pipx install git+https://github.com/pekman/yle-subtitle-dl.git
3. you probably also want to install yle-dl

Usage

yle-subtitle-dl [options] URL OUTPUT_BASENAME

Run yle-subtitle-dl --help for full list of options.

How to use with yle-dl

The right start time is needed to minimize timing mismatch between video and subtitles. Unfortunately ffmpeg, and thus yle-dl, doesn't support an absolute start time like our --start-time, which makes synchronization difficult. Here are some ways to minimize the timing mismatch:

Start both yle-dl and yle-subtitle-dl at the same time:

> yle-dl --showurl https://areena.yle.fi/tv/suorat/yle-tv1
https://example.net/hls/live/notarealurl/yletv1fin/index.m3u8

> yle-dl -o yle1.mkv --duration 1800 \
    https://areena.yle.fi/tv/suorat/yle-tv1 & \
  yle-subtitle-dl -o yle1 --duration 1800 \
    https://example.net/hls/live/notarealurl/yletv1fin/index.m3u8

Or with tmux:

> tmux new-session \
    'yle-dl -o yle1.mkv --duration 1800 https://areena.yle.fi/tv/suorat/yle-tv1' \
    ';' \
    new-window \
    "yle-subtitle-dl -o yle1 --duration 1800 $(yle-dl --showurl https://areena.yle.fi/tv/suorat/yle-tv1)"

Run yle-dl first, then time travel to the past (this seems to work for several hours):

> start=$(date -Ins); \
    yle-dl -o yle1.mkv --duration 1800 \
      https://areena.yle.fi/tv/suorat/yle-tv1
...
<time passes>
...

> yle-subtitle-dl -o yle1 --start_time "$start" --duration 1800 \
    $(yle-dl --showurl https://areena.yle.fi/tv/suorat/yle-tv1)

Known issues

• There may be some seconds worth of extra subtitles at the end after the time given in duration or end time. This should be harmless.

• There may be duplicate subtitles so that the second one starts when the first one ends. This should be invisible when playing.