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• why type casting on non-pointer struct give syntax error

  1er avril 2020, par Sany Liew

  I am using Visual C++ express 2008 try to compile code similar to below :

  



  no problem

  



  {
  ...
  AVRational test = {1, 1000};
  ...
}


  



  but has problem when it is as below :

  



  {
  ...
  AVRational test = (AVRational){1, 1000};
  ...
}


  



  gave errors :

  



  1>..\..\..\projects\test\xyz.cpp(1139) : error C2059: syntax error : '{'
1>..\..\..\projects\test\xyz.cpp(1139) : error C2143: syntax error : missing   ';' before '{'
1>..\..\..\projects\test\xyz.cpp(1139) : error C2143: syntax error : missing ';' before '}'


  



  where AVRational (ffmpeg.org library) is defined as :

  



  typedef struct AVRational{
    int num; ///< numerator
    int den; ///< denominator
} AVRational;


  



  FFmpeg come with some pre-define value such as

  



  #define AV_TIME_BASE_Q (AVRational){1, AV_TIME_BASE}


  



  which is used as below

  



  av_rescale_q(seek_target, AV_TIME_BASE_Q, pFormatCtx->streams[stream_index]->time_base);


  



  will failed to compile on Visual C++ express 2008

  



  It seem like the same code will be compiled with no error/warning on gcc compiler. Why I get this error on VC++ ? Is it a C/C++ standard way to do casting on struct value ? Anyway I can avoid this error while still able to use the defined AV_TIME_BASE_Q ?

  


• FFmpeg : A few errors including invalid frame size and incomplete frame

  8 février 2019, par Abs

  I use this ffmpeg command to take clips from a large VOB files that is on a DVD :

  ffmpeg.exe -i E:\VTS_02_2.vob -ss 00:00:57 -t 00:16:15 vids\VTS_02_2.vob

  It worked first for a VOB file but then I got these errors :

  c:\ffmpeg>ffmpeg.exe -i E:\VTS_02_2.vob -ss 00:00:57 -t 00:16:15 vids\VTS_02_2.vob
  
  FFmpeg version SVN-r15625, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  
    configuration: --enable-memalign-hack --enable-postproc --enable-swscale --enable-g
  
  l --enable-libfaac --enable-libfaad --enable-libgsm --enable-libmp3lame --enable-libv
  
  rbis --enable-libtheora --enable-libx264 --enable-libxvid --disable-ffserver --disabl
  
  -vhook --enable-avisynth --enable-pthreads
  
    libavutil     49.12. 0 / 49.12. 0
  
    libavcodec    52. 0. 0 / 52. 0. 0
  
    libavformat   52.22. 1 / 52.22. 1
  
    libavdevice   52. 1. 0 / 52. 1. 0
  
    libswscale     0. 6. 1 /  0. 6. 1
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
    built on Oct 16 2008 05:40:02, gcc: 4.2.4 (TDM-1 for MinGW)
  
  Input #0, mpeg, from 'E:\VTS_02_2.vob':
  
    Duration: 00:17:11.61, start: 1031.828511, bitrate: 8326 kb/s
  
      Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 16:15 DAR 4:3], 9640
  
  kb/s, 25.00 tb(r)
  
      Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
  
  File 'vids\VTS_02_2.vob' already exists. Overwrite ? [y/N] y
  
  Output #0, svcd, to 'vids\VTS_02_2.vob':
  
      Stream #0.0: Video: mpeg2video, yuv420p, 720x576 [PAR 16:15 DAR 4:3], q=2-31, 200
  
  kb/s, 25.00 tb(c)
  
      Stream #0.1: Audio: mp2, 48000 Hz, stereo, s16, 64 kb/s
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
    Stream #0.1 -> #0.1
  
  Press [q] to stop encoding
  
  [ac3 @ 026D3990]frame sync error
  
  Error while decoding stream #0.1
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  [mpeg2video @ 0141B780]ac-tex damaged at 40 2
  
  [mpeg2video @ 0141B780]invalid mb type in B Frame at 3 12
  
  [mpeg2video @ 0141B780]00 motion_type at 15 16
  
  [mpeg2video @ 0141B780]mb incr damaged
  
  [mpeg2video @ 0141B780]00 motion_type at 2 21
  
  [mpeg2video @ 0141B780]00 motion_type at 44 22
  
  [mpeg2video @ 0141B780]ac-tex damaged at 43 24
  
  [mpeg2video @ 0141B780]Warning MVs not available
  
  [mpeg2video @ 0141B780]concealing 765 DC, 765 AC, 765 MV errors
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  [mpeg2video @ 0141B780]ac-tex damaged at 5 9
  
  [mpeg2video @ 0141B780]00 motion_type at 21 13
  
  [mpeg2video @ 0141B780]ac-tex damaged at 1 20
  
  [mpeg2video @ 0141B780]mb incr damaged
  
  [mpeg2video @ 0141B780]00 motion_type at 30 30
  
  [mpeg2video @ 0141B780]Warning MVs not available
  
  [mpeg2video @ 0141B780]concealing 450 DC, 450 AC, 450 MV errors
  
  [ac3 @ 026D3990]frame CRC mismatch
  
  [ac3 @ 026D3990]incomplete frame
  
  [ac3 @ 026D3990]invalid frame size
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  [mpeg2video @ 0141B780]00 motion_type at 38 15
  
  [mpeg2video @ 0141B780]00 motion_type at 30 34
  
  [mpeg2video @ 0141B780]Warning MVs not available
  
  [mpeg2video @ 0141B780]concealing 254 DC, 254 AC, 254 MV errors
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  [mpeg2video @ 0141B780]ac-tex damaged at 7 6
  
  [mpeg2video @ 0141B780]concealing 1350 DC, 1350 AC, 1350 MV errors
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  [ac3 @ 026D3990]incomplete frame
  
  [ac3 @ 026D3990]invalid frame size
  
  frame=    0 fps=  0 q=0.0 size=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  frame=    0 fps=  0 q=0.0 Lsize=       0kB time=10000000000.00 bitrate=   0.0kbits/s
  
  
  
  video:0kB audio:0kB global headers:0kB muxing overhead -1.#IND00%

  Is there a way to force ffmpeg to just give me an output ?

• Use fluent-ffmpeg to tell if a file is a video or audio

  8 mai 2021, par afterglowlee

  I am using node-fluent-ffmpeg module in NodeJS. It is very good that fluent-ffmpeg provides functions to get the metadata of a video and audio file.

  



  https://github.com/schaermu/node-fluent-ffmpeg#reading-video-metadata

  



  I have tried on Mac OS to use the "resolution" attribute in the metadata to tell if a file is audio only or video, i.e. if both resolution.w and resolution.h are 0, then this file is an audio. This work fine on Mac OS. But some strange things happened that this doesn't work on Windows platform (I have tried Windows 7 64bit and Windows 2008) using the latest ffmpeg. Even though I put a .mp3 file through fluent-ffmpeg,the result looks something like this :

  



  video:
{
  container:'mp3',
  ...
  resolution: {w:300,h:300},
  resolutionSquare: {w:300,h:300},
  aspectString: '1:1',
  ...
}
audio:
{
  codec:'mp3',
  bitrate:64,
  sample_rate:44100,
  stream:0,
  channels:1
}


  



  I am not why there is a "resolution" since it is a pure audio file. So is there any solid way to find out if the file is audio only or video from the metadata ? Or should I use ffmpeg commandline to find it out ?