[FFmpeg-trac] #8109(undetermined:reopened): Long loading delay for VfW codecs in Matroska

[FFmpeg]

#8109: Long loading delay for VfW codecs in Matroska
-------------------------------------+-------------------------------------
             Reporter:  Austin       |                    Owner:
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by jamrial):

 * status:  closed => reopened
 * resolution:  worksforme =>
 * reproduced:  0 => 1


Comment:

 I can reproduce some delay, but not 20+ seconds. This is on Windows, same
 as the ticket's reporter.

 The -benchmark option doesn't reflect it, only the external time tool
 does.

 {{{
 $ time ./ffmpeg -loglevel verbose -benchmark -ss 00:50:00.000 -i
 /d/MKVTest.mkv -c:v copy -t 1 -f matroska -y NUL
 ffmpeg version N-94715-ga12b629ae1 Copyright (c) 2000-2019 the FFmpeg
 developers
   built with gcc 9.2.0 (Rev1, Built by MSYS2 project)
   configuration: --enable-gpl --enable-nonfree --enable-libxml2 --enable-
 libaom --enable-libdav1d --enable-libfdk-aac --enable-libmp3lame --enable-
 libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-
 libx265 --enable-libwebp --enable-libzimg --cpu=haswell --extra-
 cflags='-D_WIN32_WINNT=0x0A00' --cc='ccache gcc' --disable-avx512
 --samples=../samples --prefix=/mingw64
   libavutil      56. 34.100 / 56. 34.100
   libavcodec     58. 56.101 / 58. 56.101
   libavformat    58. 31.104 / 58. 31.104
   libavdevice    58.  9.100 / 58.  9.100
   libavfilter     7. 58.102 /  7. 58.102
   libswscale      5.  6.100 /  5.  6.100
   libswresample   3.  6.100 /  3.  6.100
   libpostproc    55.  6.100 / 55.  6.100
 [matroska,webm @ 0000000003a68120] parser not found for codec utvideo,
 packets or times may be invalid.
     Last message repeated 1 times
 Input #0, matroska,webm, from 'D:/MKVTest.mkv':
   Metadata:
     ENCODER         : Lavf58.31.104
   Duration: 01:00:00.00, start: 0.000000, bitrate: 18374 kb/s
     Stream #0:0: Video: utvideo, 1 reference frame (ULRG / 0x47524C55),
 gbrp, 640x360, 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
     Metadata:
       ENCODER         : Lavc58.56.101 utvideo
       DURATION        : 01:00:00.000000000
 Output #0, matroska, to 'NUL':
   Metadata:
     encoder         : Lavf58.31.104
     Stream #0:0: Video: utvideo, 1 reference frame (ULRG / 0x47524C55),
 gbrp, 640x360 (0x0), q=2-31, 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
     Metadata:
       ENCODER         : Lavc58.56.101 utvideo
       DURATION        : 01:00:00.000000000
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
 Press [q] to stop, [?] for help
 No more output streams to write to, finishing.
 frame=   25 fps=0.0 q=-1.0 Lsize=    2244kB time=00:00:00.96
 bitrate=19126.8kbits/s speed= 235x
 video:2242kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.078753%
 Input file #0 (D:/MKVTest.mkv):
   Input stream #0:0 (video): 26 packets read (2387632 bytes);
   Total: 26 packets (2387632 bytes) demuxed
 Output file #0 (NUL):
   Output stream #0:0 (video): 25 packets muxed (2295800 bytes);
   Total: 25 packets (2295800 bytes) muxed
 bench: utime=0.000s stime=0.000s rtime=0.004s
 bench: maxrss=31844kB
 [AVIOContext @ 0000000004070ec0] Statistics: 8 seeks, 31 writeouts
 [AVIOContext @ 0000000003a692e0] Statistics: 4412112 bytes read, 3 seeks

 real    0m4.607s
 user    0m0.000s
 sys     0m0.000s
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8109#comment:2>
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