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IMFSinkWriter produces a bit bad MPEG4 audio files RRS feed

  • Question

  • Good day.

    It seems MP4 audio files, created using IMFSinkWriter, are "a bit bad". To reproduce The problem:

    - Create a MPEG4 file with only one audio stream (without a video stream) using iTunes or ffmpeg. The file should has quite long duration (say ~1hour). It seems format attributes (sample rate, bit rate,...) can be arbitrary.

    - Copy the file using MFCopy Media Foundation sample without re-encoding the stream:

    mfcopy infile.mp4 outfile.mp4

    You will see that the copying is performed quite quickly.

    - Perform copying of the result file using MFCopy without re-encoding:

    mfcopy outfile.mp4 outfile2.mp4

    You will see, that the second copying is significantly slower, and the process of copying is visibly slow down to the end of file. I suppose, that the problem relates to pure audio files created through IMFSinkWriter. If we will try to execute above steps on files with video streams, all the copyings are quck.

     

    Friday, April 29, 2011 5:01 PM