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• avutil/timecode : fix av_timecode_get_smpte_from_framenum with 50/60 fps

  20 juillet 2020, par Marton Balint

  avutil/timecode : fix av_timecode_get_smpte_from_framenum with 50/60 fps
  SMPTE 12M timecode can only count frames up to 39, because the tens-of-frames
  
  value is stored in 2 bit. In order to resolve this 50/60 fps SMPTE timecode is
  
  using the field bit (which is the same bit as the phase correction bit) to
  
  signal the least significant bit of a 50/60 fps timecode. See SMPTE ST
  
  12-1:2014 section 12.1.
  Therefore we slightly change the format of the return value of
  
  av_timecode_get_smpte_from_framenum and AV_FRAME_DATA_S12M_TIMECODE and start
  
  using the previously unused Phase Correction bit as Field bit. (As the SMPTE
  
  standard suggests)
  We add 50/60 fps support to av_timecode_get_smpte_from_framenum by calling the
  
  recently added av_timecode_get_smpte function in it which already handles this
  
  properly.
  This change affects the decklink indev and the DV and MXF muxers. MXF has no
  
  fate test for 50/60fps content, DV does, therefore the changes.
  MediaInfo (a recent version) confirms that half-frame timecode must be inserted
  
  to DV. MXFInspect confirms valid timecode insertion to the System Item of MXF
  
  files. For MXF, also see EBU R122.
  Note that for DV the field flag is not used because in the HDV specs (SMPTE
  
  370M) it is still defined as biphase mark polarity correction flag. So it
  
  should not matter that the DV muxer overrides the field bit.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavutil/timecode.c
  • [DH] libavutil/timecode.h
  • [DH] tests/ref/vsynth/vsynth1-dv-hd
  • [DH] tests/ref/vsynth/vsynth2-dv-hd
  • [DH] tests/ref/vsynth/vsynth3-dv-hd
  • [DH] tests/ref/vsynth/vsynth_lena-dv-hd

• Setting B frames in a video with ffmpeg

  4 juin 2021, par roberutsu

  According to ffmpeg manual, setting -g is to define space between "I" frames, and setting -bf to use "B" frames. The former I got, but the latter not.

  



  The goal : I'm trying to have a video with a GOP 3,12 (M= 3, N=12).
That means : 2 "B" frames separating each "P" frames, and "I" frames with 12 frames of distance. Or simply : "IBBPBBPBBPBBI"

  



  I think that I got only the N=12, using the commands below :

  



  

  1. ffmpeg -s cif -r 30 -b 64000 -bt 3200 -g 12 -y -i video.yuv -vcodec mpeg4 video.m4v

  


  2. MP4Box -hint -mtu 1460 -fps 30 -add video.m4v video.mp4

  


  3. ffmpeg -y -i video.mp4 video_ref.yuv

  


  4. ../cmd/psnr 352 288 420 video.yuv video_ref.yuv > psnr_ref.txt

  


  5. ../cmd/mp4trace -f -s 192.168.0.2 12346 video.mp4 > trace

  


  6. head -n 20 trace

  


  



  Result :

  



  [robert@10-2Fontes]$ head -n 20 trace
1   H   12002   9   0.000
2   P   11479   8   0.034
3   P   12021   9   0.066
4   P   11239   8   0.099
5   P   5407    4   0.134
6   P   2735    2   0.166
7   P   1014    1   0.199
8   P   850 1   0.232
9   P   619 1   0.265
10  P   979 1   0.298
11  P   813 1   0.331
12  P   806 1   0.364
13  H   5109    4   0.396


  



  *Note, the most important is the command -g 12 in ffmpeg, but I writing all the commands. The video that I'm using is the "highway", from cif page videos : http://www2.tkn.tu-berlin.de/research/evalvid/cif.html

  



  I don't know why the result trace is using "H" instead of "I".

  



  I tried to put -bf 2 in ffmpeg command, but did not worked (I think because I saw no "B" indications in the result)

  



  List item

  



  ffmpeg -s cif -r 30 -b 64000 -bt 3200 -g 12 -bf 2 -y -i video.yuv -vcodec mpeg4 video.m4v


  



  Result :

  



  [robert@10-2Fontes]$ head -n 20 trace
1   H   12002   9   0.001
2   P   11479   8   0.034
3   P   12021   9   0.067
4   P   11239   8   0.100
5   P   5407    4   0.132
6   P   2735    2   0.166
7   P   1014    1   0.199
8   P   850 1   0.232
9   P   619 1   0.265
10  P   979 1   0.298
11  P   813 1   0.331
12  P   806 1   0.363
13  H   5109    4   0.400


  


• using for loop in powershell with ffmpeg to create thumbnails

  29 septembre 2020, par blue

  I have this basic for loop combined with ffmpeg that creates thumbnails for each video.

  


  Could anyone help me figure out why it doesn't work ? I don't really know much about powsershell.

  


  If i were to use a regular array it works but when i use a pre-sized array it does not.
EDIT :
somehow figured it out, i should have included the extention'.png' in the array instead of adding at the end of the for loop.i also didn't define a size for the array.

  


  $files = @(Get-ChildItem -Path 'D:\other stuff\ffmpeg test\*.mp4')
$filetext = @()
$test = 'd.png'

  
 for ($i=0; $i -lt $files.length; $i++){ 
 $filetext += (Get-Item $files[$i]).Basename + '.png'
 ffmpeg -i $files[$i] -ss 00:00:01  -vframes 1 $filetext[$i] 

}


  


  PS D:\other stuff\ffmpeg test> $files = @(Get-ChildItem -Path 'D:\other stuff\ffmpeg test\*.mp4')
$filetext = [Object[]]::new(100)


for ($i=0; $i -lt $files.length; $i++) {
  $filetext[$i] = % {$files[$i].BaseName}
  ffmpeg -i $files[$i] -ss 00:00:01  -vframes 1 $filetext[$i]'.png'
    
}

ffmpeg : ffmpeg version 2020-09-27-git-a3a6b56200-full_build-www.gyan.dev Copyright (c) 2000-2020 the FFmpeg developers
At line:7 char:3
+   ffmpeg -i $files[$i] -ss 00:00:01  -vframes 1 $filetext[$i]'.png'
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (ffmpeg version ...mpeg developers:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
 
  built with gcc 10.2.0 (Rev3, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib 
--enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 
--enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm 
--enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt 
--enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libwavpack --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus 
--enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      56. 59.100 / 56. 59.100
  libavcodec     58.108.100 / 58.108.100
  libavformat    58. 59.100 / 58. 59.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\other stuff\ffmpeg test\sample1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf56.25.101
  Duration: 00:00:30.87, start: 0.000000, bitrate: 
411 kb/s
    Stream #0:
0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 460x258 [SAR 1:1 DAR 230:129], 276 kb/s, 
29.97 fps, 
29.97 tbr, 
11988 tbn, 
59.94 tbc
 (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:
1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : 
SoundHandler
[NULL @ 000001c582d03700] 
Unable to find a suitable output format for 'sample1'
sample1: Invalid argument
ffmpeg : ffmpeg version 2020-09-27-git-a3a6b56200-full_build-www.gyan.dev Copyright (c) 2000-2020 the FFmpeg developers
At line:7 char:3
+   ffmpeg -i $files[$i] -ss 00:00:01  -vframes 1 $filetext[$i]'.png'
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (ffmpeg version ...mpeg developers:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
 
  built with gcc 10.2.0 (Rev3, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib 
--enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 
--enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm 
--enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt 
--enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libwavpack --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus 
--enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      56. 59.100 / 56. 59.100
  libavcodec     58.108.100 / 58.108.100
  libavformat    58. 59.100 / 58. 59.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\other stuff\ffmpeg test\sample2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf56.25.101
  Duration: 
00:00:24.9
3
, start:
 
0.000000, bitrate: 789 kb/s
    Stream #0:
0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 460x460 [SAR 1:1 DAR 1:1], 658 kb/s, 30 fps, 30 tbr, 15360 tbn, 
60 tbc (default)
    Metadata:
      handler_name    : 
VideoHandler
    Stream #0:
1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[NULL @ 00000267c8bb0540] 
Unable to find a suitable output format for 'sample2'
sample2: Invalid argument