Crash in ffmpeg when switching audio track in a network stream

[xyzz]

mpv version and platform

mpv: d690ee0
ffmpeg: 3f887440677328c9cfed97ad81d14051ffa32aae

(compiled with mpv-build)

Reproduction steps

1. Start a twitch stream, e.g. mpv https://www.twitch.tv/aimbotcalvin
2. Rapidly click on the audio track icon in the OSD (sometimes it takes 2 clicks, sometimes up to 10)

Expected behavior

mpv does not crash

Actual behavior

mpv crashes :(

Log file

Output from gdb:

[...]
(Buffering) AV: 00:00:08 / unknown A-V:  0.000 Cache:  0s+6KB
Track switched:
 (+) Video --vid=1 (h264 1280x720)
     Audio --aid=1 (aac 2ch 44100Hz)
(Buffering) V: 00:00:08 / unknown Cache:  0s+6KB
Track switched:
 (+) Video --vid=1 (h264 1280x720)
 (+) Audio --aid=1 (aac 2ch 44100Hz)
(Buffering) AV: 00:00:08 / unknown A-V:  0.000 Cache:  0s+6KB
Thread 8 "mpv/demux" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe4ee4700 (LWP 31463)]
ffurl_get_short_seek (h=0x0) at src/libavformat/avio.c:650
650	    if (!h->prot->url_get_short_seek)
(gdb) bt
#0  ffurl_get_short_seek (h=0x0) at src/libavformat/avio.c:650
#1  0x00005555559e4f98 in avio_seek (s=0x7fffd0397660, offset=8846, whence=<optimized out>, whence@entry=0) at src/libavformat/aviobuf.c:275
#2  0x0000555555afe26d in seek_frame_generic (flags=1, timestamp=850835880, stream_index=1, s=0x7fffd063b4c0) at src/libavformat/utils.c:2365
#3  seek_frame_internal (flags=1, timestamp=850835880, stream_index=1, s=0x7fffd063b4c0) at src/libavformat/utils.c:2444
#4  av_seek_frame (s=0x7fffd063b4c0, stream_index=stream_index@entry=-1, timestamp=timestamp@entry=9453732000, flags=flags@entry=1) at src/libavformat/utils.c:2464
#5  0x000055555570c7ec in demux_seek_lavf (demuxer=0x7fffd030faa0, seek_pts=<optimized out>, flags=<optimized out>) at ../demux/demux_lavf.c:1027
#6  0x00005555557042e7 in execute_seek (in=0x7fffd010edd0) at ../demux/demux.c:1400
#7  0x0000555555706425 in thread_work (in=0x7fffd010edd0) at ../demux/demux.c:1421
#8  0x0000555555706854 in demux_thread (pctx=0x7fffd010edd0) at ../demux/demux.c:1444
#9  0x00007fffef0b408a in start_thread () from /usr/lib/libpthread.so.0
#10 0x00007fffef3c142f in clone () from /usr/lib/libc.so.6

Sample files

I haven't been able to reproduce this with a local file.

---

Not sure if this is an mpv or ffmpeg issue, not sure how to reproduce with just ffmpeg.

[CounterPillow]

Can reproduce with

$ mpv --version
mpv 0.27.0-548-g3c4667c862 (C) 2000-2017 mpv/MPlayer/mplayer2 projects
 built on Sun Dec 17 06:45:33 CET 2017
ffmpeg library versions:
   libavutil       56.6.100
   libavcodec      58.8.100
   libavformat     58.3.100
   libswscale      5.0.101
   libavfilter     7.7.100
   libswresample   3.0.101
ffmpeg version: N-89514-g0ee143558d

it first stalls buffering for a while, then a few seconds later appears to crash altogether.

[xyzz]

Same issue when seeking a live stream. Also when googling for that function name, I found this https://trac.ffmpeg.org/ticket/6846 which might be relevant.

[Jj0YzL5nvJ]

Same here:

mpv 0.27.0-530-g6c8e7daebb (C) 2000-2017 mpv/MPlayer/mplayer2 projects
 built on Mon Dec 11 18:56:04 MST 2017
ffmpeg library versions:
   libavutil       56.5.100
   libavcodec      58.6.103
   libavformat     58.3.100
   libswscale      5.0.101
   libavfilter     7.7.100
   libswresample   3.0.101
ffmpeg version: N-89466-g555119bd76

Log file
https://0x0.st/sX0B.txt

[ghost]

Almost certainly ffmpeg bugs. fffmpeg's HLS demuxer isn't very good.

[Jj0YzL5nvJ]

Adding --no-video you can obtain such mention in the log... https://0x0.st/sX0S.txt

[ghost]

Seems like this is the ffmpeg issue, which seems to confirm that it's a ffmpeg bug: https://trac.ffmpeg.org/ticket/6846

[Jj0YzL5nvJ]

I can't reproduce anymore:

mpv 0.28.0-72-ge894f75bb5 Copyright © 2000-2018 mpv/MPlayer/mplayer2 projects
 built on Wed Jan  3 19:04:39 MST 2018
ffmpeg library versions:
   libavutil       56.7.100
   libavcodec      58.9.100
   libavformat     58.3.100
   libswscale      5.0.101
   libavfilter     7.9.100
   libswresample   3.0.101
ffmpeg version: N-89682-g88cbd25b19

[kevmitch]

should be fixed by FFmpeg/FFmpeg@be4dfbf