[FFmpeg-trac] #4258(avcodec:new): HEVC Decoder Hang in Multi-threaded Slice Type Decoding

[FFmpeg]

#4258: HEVC Decoder Hang in Multi-threaded Slice Type Decoding
---------------------------------------+-----------------------------------
             Reporter:  jlsantiago0    |                    Owner:
                 Type:  defect         |                   Status:  new
             Priority:  important      |                Component:  avcodec
              Version:  git-master     |               Resolution:
             Keywords:  hevc deadlock  |               Blocked By:
             Blocking:                 |  Reproduced by developer:  0
Analyzed by developer:  0              |
---------------------------------------+-----------------------------------

Comment (by jlsantiago0):

 This issue is still happening. Minor bitstream corruption can cause the
 HEVC Decoder running Multi-Threaded slice type to deadlock. Observed on
 Linux using Pthreads.

 The decoder deadlocks inside the call to avcodec_decode_video2() which
 never returns. All of the decoder threads are blocked in
 ff_thread_await_progress2().

 It has been very hard to catch, but I have a mechanism to reproduce it now
 every time. On my system is will deadlock anywhere within 20 minutes to 5
 or 6 hours. To reproduce the issue stream the TS file located at
 http://162.97.176.4/ffmpeg-issue-4258-test-case.ts (NOTE file is approx
 300MB) via FFMPEG to UDP localhost and decode the stream in a second
 instance of FFMPEG. For instance:

 {{{
 $ while true ; do \
   ffmpeg -re -i ./ffmpeg-issue-4258-test-case.ts \
      -codec copy -f mpegts udp://127.0.0.1:12345 \
 done
 }}}

 Then decode the stream via:


 {{{
 $ ffmpeg_g -vcodec hevc -threads 12 -thread_type slice \
   -i udp://:12345 -f null /dev/null
 }}}

 Here is a recent run where it deadlocked after almost 2 hours:

 {{{
 ffmpeg version 2.8.git-VF Copyright (c) 2000-2015 the FFmpeg developers
   built with gcc 5.2.0 (GCC)
   configuration: --extra-version=VF
 --prefix=/mnt/centshare/ffmpeg/trunk/build/build-linux/stage --extra-
 cflags='-I/mnt/centshare/ffmpeg/trunk/build/../src/libavformat
 -I/mnt/centshare/ffmpeg/trunk/build/../src/libavcodec -I/usr/include/SDL
 -D_GNU_SOURCE=1 -D_REENTRANT -ggdb' --extra-
 ldflags='-L/mnt/centshare/ffmpeg/trunk/build/build-linux/stage/lib
 -Wl,-rpath -Wl,/mnt/centshare/ffmpeg/trunk/build/build-linux/stage/lib
 -I/usr/include/SDL -D_GNU_SOURCE=1 -D_REENTRANT -L/usr/lib -lSDL
 -lpthread' --enable-static --enable-avfilter --enable-pthreads --enable-
 zlib --enable-bzlib --enable-runtime-cpudetect --enable-hardcoded-tables
   libavutil      55.  1.100 / 55.  1.100
   libavcodec     57.  1.100 / 57.  1.100
   libavformat    57.  0.100 / 57.  0.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6.  1.100 /  6.  1.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.100 /  2.  0.100
 Input #0, mpegts, from 'udp://:12345':
   Duration: N/A, start: 1.400000, bitrate: N/A
   Program 1
     Metadata:
       service_name    : Service01
       service_provider: FFmpeg
     Stream #0:0[0x100]: Video: hevc (Main) ([36][0][0][0] / 0x0024),
 yuv420p(tv), 960x1080 [SAR 2:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn,
 29.97 tbc
     Stream #0:1[0x101]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000
 Hz, stereo, fltp, 123 kb/s
 Output #0, null, to '/dev/null':
   Metadata:
     encoder         : Lavf57.0.100
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 960x1080
 [SAR 2:1 DAR 16:9], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc
     Metadata:
       encoder         : Lavc57.1.100 rawvideo
     Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
     Metadata:
       encoder         : Lavc57.1.100 pcm_s16le
 Stream mapping:
   Stream #0:0 -> #0:0 (hevc (native) -> rawvideo (native))
   Stream #0:1 -> #0:1 (aac (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 frame=  107 fps=0.0 q=-0.0 size=N/A time=00:00:03.87 bitrate=N/A
 frame=  180 fps=178 q=-0.0 size=N/A time=00:00:06.30 bitrate=N/A
 frame=  195 fps=128 q=-0.0 size=N/A time=00:00:06.80 bitrate=N/A
 frame=  213 fps=103 q=-0.0 size=N/A time=00:00:07.40 bitrate=N/A
 frame=  229 fps= 88 q=-0.0 size=N/A time=00:00:07.94 bitrate=N/A
 ...
 <SNIP>
 ...
 frame=193019 fps= 30 q=-0.0 size=N/A time=01:47:22.26 bitrate=N/A
 frame=193034 fps= 30 q=-0.0 size=N/A time=01:47:22.76 bitrate=N/A
 frame=193053 fps= 30 q=-0.0 size=N/A time=01:47:23.40 bitrate=N/A
 frame=193068 fps= 30 q=-0.0 size=N/A time=01:47:23.90 bitrate=N/A
 [udp @ 0x37d2de0] Circular buffer overrun. To avoid, increase fifo_size
 URL option. To survive in such case, use overrun_nonfatal option

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4258#comment:7>
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