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• ffmpeg decode example using vda acceleration ?

  18 mars 2015, par Bill Yan

  I’m testing the vda hw accelerated decoder of ffmpeg, but have no luck so far.

  the command line I use is this :

  ./ffmpeg -hwaccel vda -i ~/Downloads/big_buck_bunny_720p_surround.avi -c:v rawvideo -pix_fmt yuv420p out.yuv

  (the input video can be downloaded here : http://mirrorblender.top-ix.org/peach/bigbuckbunny_movies/big_buck_bunny_720p_surround.avi)

  but it uses the sw decoder, instead of the requested vda hw decoder.

  I debugged ffmpeg.c, and found out that in the function get_format :

  if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
  
      break;

  the desc->flag isn’t set with AV_PIX_FMT_FLAG_HWACCEL, so it skips the hw acceleration initialization.

  the reason is because the pix_fmt is set to AV_PIX_FMT_NONE for some reason, instead of yuv420p as specified by the command.

  I then changed the command to this :

  ./ffmpeg -hwaccel vda -i ~/Downloads/big_buck_bunny_720p_surround.avi -c:v rawvideo -pix_fmt vda_vld out.yuv

  but what I got was :

  Impossible to convert between the formats supported by the filter 'format' and the filter 'auto-inserted scaler 0'
  
  
  
  
  
  Error opening filters!

  Can you please show me an example of using ffmpeg to dump the above video into yuv using the vda hw decoder ?

  UPDATE from the ffmpeg mailist.

  I was told to try the following command instead :

      ./ffmpeg -vcodec h264_vda -i ~/Downloads/big_buck_bunny_720p_surround.avi out.yuv

  but this is what I got :

  ./ffmpeg -vcodec h264_vda -i ~/Downloads/big_buck_bunny_720p_surround.avi out.yuv
  
  
  
  ffmpeg version 2.6.1 Copyright (c) 2000-2015 the FFmpeg developers
  
  built with Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
  
  configuration: 
  
  libavutil      54. 20.100 / 54. 20.100
  
  libavcodec     56. 26.100 / 56. 26.100
  
  libavformat    56. 25.101 / 56. 25.101
  
  libavdevice    56.  4.100 / 56.  4.100
  
  libavfilter     5. 11.102 /  5. 11.102
  
  libswscale      3.  1.101 /  3.  1.101
  
  libswresample   1.  1.100 /  1.  1.100
  
  [10:20:50.169] vtDecompressionDuctCreate signalled err=-8973 (err) (Could not select and open decoder instance) at /SourceCache/CoreMedia_frameworks/CoreMedia-1562.107/Sources/VideoToolbox/VTDecompressionSession.c line 1181
  
  [h264_vda @ 0x7f9feb034600] Failed to init VDA decoder: -12473.
  
  [avi @ 0x7f9feb00da00] Failed to open codec in av_find_stream_info
  
  [NULL @ 0x7f9feb034600] missing picture in access unit with size 9960
  
  [10:20:50.252] vtDecompressionDuctCreate signalled err=-8973 (err) (Could not select and open decoder instance) at /SourceCache/CoreMedia_frameworks/CoreMedia-1562.107/Sources/VideoToolbox/VTDecompressionSession.c line 1181
  
  [h264_vda @ 0x7f9feb034600] Failed to init VDA decoder: -12473.
  
  [NULL @ 0x7f9feb034600] missing picture in access unit with size 457

  the reason I wanted to try this was because I wanted to use vda with libavcodec in the first place. but the problem I saw was exactly the above. looks like ffmpeg has the same issue.

• Rotated video with ffmpeg doesn't play in flowplayer in IE9

  17 octobre 2013, par yoshi

  I have a script that rotates videos 90 degrees and then the videos are displayed on a web page using flowplayer (HTML5 version, not Flash). After the video is rotated once it does not play in IE9 but plays without any other problems in Chrome and Firefox.
  The error message is : Video file not found.

  I've looked in IE9's developer tools console, in the network tab and the browser streams the whole video.

  The following is the ffmpeg command I use to rotate and convert the video :

  ffmpeg -i input.mov -y -r 30 -b 4M -vf 'transpose=1,scale=800:trunc(ow/a/2)*2' -ar 48000 -vcodec libx264 -profile baseline -preset slow -level 2.2 output.mp4

  This is the input file which I used : https://dl.dropboxusercontent.com/u/37994/local%20capture.mov

  This is the output video : https://dl.dropboxusercontent.com/u/37994/local%20capture%20rotated.mp4

  The input video from above is a screen capture made using QuickTime on Mac OS.

  This also happened for this video : http://mirrorblender.top-ix.org/peach/bigbuckbunny_movies/big_buck_bunny_480p_h264.mov
  And also this one : https://dl.dropboxusercontent.com/u/37994/clipcanvas_14348_offline.mp4

  This didn't happen for the sample .mov from here : http://support.apple.com/kb/ht1425

  If I run the command twice, meaning I rotate the video 90 degrees and then I rotate the output using the same command once more, the problem disappears, but I need to be able to rotate only 90 degrees.

  This problem doesn't happen if I put IE9 in IE7 or IE8 compatibility mode.

  I was thinking that maybe the problem was how the server serves the video but there's no problem with other videos.

  I looked at the metadata with ffmpeg but didn't see anything significant.

  I already have AddType video/mp4 .mp4 in .htaccess.

  I can't seem to pin down what's causing this problem.

  Edit :

  Request in IE9
  

  Response in IE9
  

• Revision 30966 : eviter le moche ’doctype_ecrire’ lors de l’upgrade

  17 août 2009, par fil@… — Log

  eviter le moche ’doctype_ecrire’ lors de l’upgrade