[FFmpeg-trac] #6511(avformat:new): The ouput file has no video data at the beginning when transcoding MP4 file

FFmpeg trac at avcodec.org
Wed Jul 5 09:53:14 EEST 2017


#6511: The ouput file has no video data at the beginning when transcoding MP4 file
-----------------------------------+--------------------------------------
             Reporter:  GalaDOS    |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  avformat   |                  Version:  git-master
             Keywords:  mp4, elst  |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
-----------------------------------+--------------------------------------
 '''Summary of the bug:'''
 When transcoding some MP4 files containing Edit List Box whose media_time
 value is not zero, the first GOP could not be decode well (I think it is
 because the IDR frame is skiped by the demuxer). This causes the output
 files have no video data at the beginning.

 '''How to reproduce:'''
 You can reproduce this with file attached.
 My ffmpeg version: git master head (2017-07-05).
 {{{
 $ ./ffmpeg -y -i ~/Public/elst_box_skip_2frames.mp4
 ~/Public/elst_box_skip_2frames_output.mp4
 ffmpeg version 3.3.git-c8cfbc6 Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-4)
   configuration: --prefix=/home/zx/ffmpeg_build --extra-
 cflags=-I/home/zx/ffmpeg_build/include --extra-
 ldflags='-L/home/zx/ffmpeg_build/lib -ldl' --bindir=/home/zx/bin --pkg-
 config-flags=--static --enable-gpl --enable-nonfree --enable-libfdk_aac
 --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-
 libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-
 libmfx --enable-nonfree --disable-shared --enable-static --disable-debug
   libavutil      55. 67.100 / 55. 67.100
   libavcodec     57.100.103 / 57.100.103
   libavformat    57. 75.100 / 57. 75.100
   libavdevice    57.  7.100 / 57.  7.100
   libavfilter     6. 94.100 /  6. 94.100
   libswscale      4.  7.101 /  4.  7.101
   libswresample   2.  8.100 /  2.  8.100
   libpostproc    54.  6.100 / 54.  6.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
 '/home/zx/Public/elst_box_skip_2frames.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     artist          : yinyuetai.com
     album           : Yinyuetai
     date            : 06/27/17 15:08:38
     encoder         : Lavf56.40.101
     comment         : Yinyuetai-1TR1042
   Duration: 00:00:18.07, start: 0.000000, bitrate: 1099 kb/s
     Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p,
 960x540, 994 kb/s, 29 fps, 29 tbr, 29k tbn, 58 tbc (default)
     Metadata:
       handler_name    : VideoHandler
     Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
 stereo, fltp, 95 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
   Stream #0:1 -> #0:1 (aac (native) -> aac (native))
 Press [q] to stop, [?] for help
 [libx264 @ 0x43de8e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
 AVX FMA3 AVX2 LZCNT BMI2
 [libx264 @ 0x43de8e0] profile High, level 3.1
 [libx264 @ 0x43de8e0] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft
 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3
 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00
 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0
 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6
 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
 Output #0, mp4, to '/home/zx/Public/elst_box_skip_2frames_output.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     artist          : yinyuetai.com
     album           : Yinyuetai
     date            : 06/27/17 15:08:38
     comment         : Yinyuetai-1TR1042
     encoder         : Lavf57.75.100
     Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p,
 960x540, q=-1--1, 29 fps, 14848 tbn, 29 tbc (default)
     Metadata:
       handler_name    : VideoHandler
       encoder         : Lavc57.100.103 libx264
     Side data:
       cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
     Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
 stereo, fltp, 128 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
       encoder         : Lavc57.100.103 aac
 frame=  522 fps=185 q=-1.0 Lsize=    1156kB time=00:00:18.01 bitrate=
 525.6kbits/s dup=244 drop=0 speed=6.39x
 video:853kB audio:283kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 1.810231%
 [libx264 @ 0x43de8e0] frame I:3     Avg QP:19.18  size: 56207
 [libx264 @ 0x43de8e0] frame P:149   Avg QP:20.28  size:  3718
 [libx264 @ 0x43de8e0] frame B:370   Avg QP:27.01  size:   404
 [libx264 @ 0x43de8e0] consecutive B-frames:  2.1%  9.2%  2.9% 85.8%
 [libx264 @ 0x43de8e0] mb I  I16..4: 11.0% 39.9% 49.2%
 [libx264 @ 0x43de8e0] mb P  I16..4:  0.5%  0.8%  0.1%  P16..4: 27.3%  8.0%
 4.3%  0.0%  0.0%    skip:59.1%
 [libx264 @ 0x43de8e0] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 15.8%  0.3%
 0.0%  direct: 0.1%  skip:83.8%  L0:48.2% L1:49.2% BI: 2.6%
 [libx264 @ 0x43de8e0] 8x8 transform intra:46.8% inter:75.1%
 [libx264 @ 0x43de8e0] coded y,uvDC,uvAC intra: 58.5% 82.4% 57.8% inter:
 3.1% 7.0% 0.5%
 [libx264 @ 0x43de8e0] i16 v,h,dc,p: 31% 28% 11% 31%
 [libx264 @ 0x43de8e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 16% 29%  6%  6%
 7%  5%  7%  6%
 [libx264 @ 0x43de8e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 18%  9% 10% 10%
 10%  7%  8%  6%
 [libx264 @ 0x43de8e0] i8c dc,h,v,p: 47% 23% 19% 11%
 [libx264 @ 0x43de8e0] Weighted P-Frames: Y:0.0% UV:0.0%
 [libx264 @ 0x43de8e0] ref P L0: 67.2% 14.5% 14.1%  4.2%
 [libx264 @ 0x43de8e0] ref B L0: 92.5%  6.6%  0.9%
 [libx264 @ 0x43de8e0] ref B L1: 98.8%  1.2%
 [libx264 @ 0x43de8e0] kb/s:387.70
 [aac @ 0x43df8a0] Qavg: 1133.271

 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6511>
FFmpeg <https://ffmpeg.org>
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