#11444: Overflow-2 in start_time_realtime calculation in rtsp.c
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Reporter: | Type: defect
IncrediBlame |
Status: new | Priority: normal
Component: ffmpeg | Version: git-
Keywords: | master
start_time_realtime RTSP RTCP | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Related to ticket #11388.
Summary of the bug:
start_time_realtime calculation was changed in release/7.1 branch:
https://github.com/FFmpeg/FFmpeg/blob/bb85423142103d694d97bad1967bd3dc55440e71/libavformat/rtsp.c#L2323
Which introduced overflow for current dates (e.g. Feb 1, 2024).
Overflow was "fixed" here:
https://github.com/FFmpeg/FFmpeg/commit/d72536008ac377164b00d214a2521e5ce604260b
Now same current dates are shown as year 1888, probably due to another
overflow.
How to reproduce:
{{{
1. Add pprintf after calculation above.
2. Build ffmpeg.
2. Run
% ffmpeg -i some_rtsp_source -c copy abc.mp4
3. If rtsp source sends RTCP SR the code will eventually be hit, but sets
the timestamp to some negative number.
}}}
Potential fix:
{{{
s->start_time_realtime = av_rescale (rtpctx->first_rtcp_ntp_time >> 2,
1000000, 1LL << 30) - NTP_OFFSET_US;
}}}
should stop any overflow.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11444>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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