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• Calling ffmpeg from subprocess.run and refering to specific directory

  27 décembre 2018, par Akalyn

  I’m trying to compile images contained in a given directory D into an mp4 video from a python script. I decided to use ffmpeg and hence called it through
  subprocess.run().

  When I issue the following command from another directory than D :

  ffmpeg -framerate 30 -pattern_type glob -i 'path/to/D/*.jpg' -vcodec libx264 -y movie.mp4

  it works fine.

  The same thing happens when I issue the command from the python script with the shell=True option :

  subprocess.run(" ".join(["ffmpeg", "-framerate", "30", "-pattern_type", "glob", "-i", "'path/to/D/*.jpg'", "-vcodec", "libx264", "-y", "movie.mp4"]), shell=True)

  However I know that relying on shell=True is not recommended. I tried using subprocess.run without that option :

  subprocess.run(["ffmpeg", "-framerate", "30", "-pattern_type", "glob", "-i", "'path/to/D/*.jpg'", "-vcodec", "libx264", "-y", "movie.mp4"])

  but it resulted in the following error :

  'path/to/D/*.jpg': No such file or directory.

  ---

  Why does the call to ffmpeg fail when calling it through subprocess.run with shell=False option ?

• lavf/vc1test : fix vc1test can't probe some RCV file.

  11 octobre 2018, par Jun Zhao

  lavf/vc1test : fix vc1test can't probe some RCV file.
  case 1 :
  
  use the hexdump -C SMM0005.rcv get :
  
                       size              skip (size - 4)
  
                        |                        |
  
                        V                        V
  
  00000000  18 00 00 c5 05 00 00 00  4d f1 0a 11 00 e0 01 00
  
  00000010  00 d0 02 00 00 0c 00 00  00 88 13 00 00 c0 65 52
  
                           ^
  
  			 |
  
  		     size + 16
  
  case 2 :
  
  same the command for SMM0015.rcv get :
  
                      size
  
                        |
  
                        V
  
  00000000  19 00 00 c5 04 00 00 00  41 f3 80 01 40 02 00 00
  
  00000010  d0 02 00 00 0c 00 00 00  00 00 00 10 00 00 00 00
  
                        ^
  
  		      |
  
  		   size + 16
  There are different the RCV file format for VC-1, vc1test
  
  just handle the case 2 now, this fix will support the case 1.
  
  (Both of test clips come from : SMPTE Recommended Practice -
  
  VC-1 Decoder and Bitstream Conformance). And I think I got
  
  a older VC-1 test clip in the case 1.
  Reviewed-by : Carl Eugen Hoyos <ceffmpeg@gmail.com>
  
  Reviewed-by : Jerome Borsboom <jerome.borsboom@carpalis.nl>
  
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : Jun Zhao <jun.zhao@intel.com>
  
  Signed-off-by : Yan, FengX <fengx.yan@intel.com>
  

  • [DH] libavformat/vc1test.c

• mp4 video fragmented using ffmpeg takes long time to start playing

  14 mai 2020, par daldoy

  When using ffmpeg, to stream the output file to S3, it is required to use "-movflags frag_keyframe", and the generated file will be a fragmented mp4.

  



  When I try to play this files from S3 it takes a long time to start playing. I have tried the recommended movflags from MDN Docs and all the possible combinations.

  



  ffmpeg -i https://notreal-bucket.s3-us-west-1.amazonaws.com/video/video.mp4 -f mp4 -movflags frag_keyframe+empty_moov pipe:1 | aws s3 cp - s3://notreal-bucket/video/output.mp4

  



  Link of the file : https://happy-testing.s3-eu-west-1.amazonaws.com/stack-overflow/help.mp4