[FFmpeg-trac] #9409(undetermined:new): Embedding some mp4 subtitles causes ffmpeg to hang
FFmpeg
trac at avcodec.org
Sun Sep 5 21:15:08 EEST 2021
#9409: Embedding some mp4 subtitles causes ffmpeg to hang
-------------------------------------+-------------------------------------
Reporter: Frank | Type: defect
Status: new | Priority: normal
Component: | Version: git-
undetermined | master
Keywords: subtitles | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
I've run into a bug when trying to embed some subtitles into an MP4 file,
ffmpeg hangs indefinitely with 100% cpu usage on one thread. When this
happens the output file stops growing and what is usually a few seconds
job simply does not finish even if left for hours.
This only started happening recently with some videos downloaded from
youtube-dl. I've tested this and it seems to be an issue with the latest
version of every 4.x branch - 4.0.6, 4.1.6, 4.2.4, 4.3.2, and the latest
git build. ffmpeg completes if I try this with the latest 3.4.8 branch,
but the subtitles are broken and do not appear when selected.
Since I'm not sure where the problem is in the subtitle I can't cut out
the problem part here for an example. I will attach one of the subtitle
files that causes the issue and include the youtube-dl command that will
download the smallest video.
youtube-dl command:
{{{
youtube-dl.exe -v -f 160+249 --merge-output-format mp4 --sub-lang bn
--write-auto-sub --embed-subs 0UlUbeaBCTg
}}}
ffmpeg command being run by youtube-dl:
{{{
ffmpeg -y -loglevel "repeat+info" -i "file:Making Flavored Rum _ Easy and
Cheap! - Part 1-0UlUbeaBCTg.mp4" -i "file:Making Flavored Rum _ Easy and
Cheap! - Part 1-0UlUbeaBCTg.bn.vtt" -map 0 -c copy -map "-0:s" -map "-0:d"
"-c:s" mov_text -map "1:0" "-metadata:s:s:0" "language=ben" "file:Making
Flavored Rum _ Easy and Cheap! - Part 1-0UlUbeaBCTg.temp.mp4"
}}}
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Ticket URL: <https://trac.ffmpeg.org/ticket/9409>
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