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• Video to image sequence export (preserving color range)

  20 août 2017, par Floating Point

  When I convert the material which is in legal range (tv) to prores, legal range is preserved, but when I export it to image sequence (tiff), I get files which are already in full range, although I try to preserver the original values with -vf "zscale=rin=limited:r=limited".

  Is ffmpeg automatically changes color range when exporting to images ?

• Streaming without Content-Length in response

  21 décembre 2023, par kain

  I'm using Node.js, Express (and connect), and fluent-ffmpeg.

  



  We want to stream audio files that are stored on Amazon S3 through http.

  



  We have all working, except that we would like to add a feature, the on-the-fly conversion of the stream through ffmpeg.

  



  This is working well, the problem is that some browsers checks in advance before actually getting the file.

  



  Incoming requests containing the Range header, for which we reply with a 206 with all the info from S3, have a fundamental problem : we need to know in advance the content-length of the file.

  



  We don't know that since it is going through ffmpeg.

  



  One solution might be to write out the resulting content-length directly on S3 when storing the file (in a special header), but this means we have to go through the pain of having queues to encode after upload just to know the size for future requests.
It also means that if we change compressor or preset we have to go through all this over again, so it is not a viable solution.

  



  We also noticed big differencies in the way Chrome and Safari request the audio tag src, but this may be discussion for another topic.

  



  Fact is that without a proper content-length header in response everything seems to break or browsers goes in an infinite loop or restart the stream at pleasure.

  



  Ideas ?

  


• Streaming without Content-Length in response

  29 août 2011, par kain

  I'm using Node.js, Express (and connect), and fluent-ffmpeg.

  We want to stream audio files that are stored on Amazon S3 through http.

  We have all working, except that we would like to add a feature, the on-the-fly conversion of the stream through ffmpeg.

  This is working well, the problem is that some browsers checks in advance before actually getting the file.

  Incoming requests containing the Range header, for which we reply with a 206 with all the info from S3, have a fundamental problem : we need to know in advance the content-length of the file.

  We don't know that since it is going through ffmpeg.

  One solution might be to write out the resulting content-length directly on S3 when storing the file (in a special header), but this means we have to go through the pain of having queues to encode after upload just to know the size for future requests.
  It also means that if we change compressor or preset we have to go through all this over again, so it is not a viable solution.

  We also noticed big differencies in the way Chrome and Safari request the audio tag src, but this may be discussion for another topic.

  Fact is that without a proper content-length header in response everything seems to break or browsers goes in an infinite loop or restart the stream at pleasure.

  Ideas ?