[FFmpeg-trac] #7351(avfilter:open): Infinite loop during concatenation with empty streams

[FFmpeg]

#7351: Infinite loop during concatenation with empty streams
-------------------------------------+-------------------------------------
             Reporter:  javer        |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:  avfilter
              Version:  git-master   |               Resolution:
             Keywords:  deadlock     |               Blocked By:
  trim concat                        |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  1            |
-------------------------------------+-------------------------------------

Comment (by javer):

 Hi Cigaes,

 It works fine with the test video as well as with the actual video which
 triggered this issue for me for the first time.

 {{{
 $ ./ffmpeg -y -i source.mp4 -filter_complex "[v] trim=0:1 [v_1]; [a]
 atrim=0:1 [a_1]; [v] trim=2:3 [v_2]; [a] atrim=2:3 [a_2]; [v_1] [a_1]
 [v_2] [a_2] concat=n=2:v=1:a=1" output.mp4
 ffmpeg version git-2018-08-10-87cc7e8 Copyright (c) 2000-2018 the FFmpeg
 developers
   built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
   configuration:
   libavutil      56. 18.102 / 56. 18.102
   libavcodec     58. 22.101 / 58. 22.101
   libavformat    58. 17.101 / 58. 17.101
   libavdevice    58.  4.101 / 58.  4.101
   libavfilter     7. 26.100 /  7. 26.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'source.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf58.12.100
   Duration: 00:00:00.22, start: 0.000000, bitrate: 88 kb/s
     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
 640x360, 34 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
     Metadata:
       handler_name    : VideoHandler
     Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono,
 fltp, 2 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
 Stream mapping:
   Stream #0:0 (h264) -> trim
   Stream #0:0 (h264) -> trim
   Stream #0:1 (aac) -> atrim
   Stream #0:1 (aac) -> atrim
   concat:out:v0 -> Stream #0:0 (mpeg4)
   concat:out:a0 -> Stream #0:1 (aac)
 Press [q] to stop, [?] for help
 Output #0, mp4, to 'output.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf58.17.101
     Stream #0:0: Video: mpeg4 (mp4v / 0x7634706D), yuv420p(progressive),
 640x360, q=2-31, 200 kb/s, 25 fps, 12800 tbn, 25 tbc (default)
     Metadata:
       encoder         : Lavc58.22.101 mpeg4
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
     Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono,
 fltp, 69 kb/s (default)
     Metadata:
       encoder         : Lavc58.22.101 aac
 frame=    5 fps=0.0 q=2.0 Lsize=       5kB time=00:00:00.21 bitrate=
 176.7kbits/s speed=11.1x
 video:3kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 47.342091%
 [aac @ 0x7f9360805000] Qavg: 62211.172
 }}}

 Thank you for the fast fix!

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7351#comment:7>
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