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• H.264 is patented. What happens when developing a commercial app in Android using H264 codec in ffmpeg ? [closed]

  26 mai 2013, par user1914692

  H.264 is patented.

  In countries where patents on software algorithms are upheld, vendors
  and commercial users of products that use H.264/AVC are expected to
  pay patent licensing royalties for the patented technology[14] that
  their products use.

  What happens when developing a commercial app in Android using H264 codec in ffmpeg ?

  Here there are two situations :
  (1) decode online video stream, and display it.

  (2) encode contents to a video file using H.264.

  [Update :]
  From what I googled, here are some simple pieces of information :
  (1) decode : free
  (2) encode : H.264 encoded internet video that is free to end users will never be charged royalties.
  On August 26, 2010 MPEG LA announced that H.264 encoded internet video that is free to end users will never be charged royalties. See Wiki H.264
  (3) encode : for other situations except the one in (2), I guess it might be for commercial use.

  For more, see Ref : "Know your rights : H.264, patent licensing, and you" 2010/05/04

• ffmpeg, HLS options, ffmpeg components for dummies ? [closed]

  10 juin 2013, par Vetal

  I am trying to make some HLS encoding with ffmpeg

  After playing a lot (in Ubuntu 12.04) with ffmpeg I realized I do not understand basic questions.

  How to make a ffmpeg "by the book" ?

  I've started a "sudo apt-get install ffmpeg"

  I finished with a manual install :

  http://ffmpeg.org/trac/ffmpeg/wiki/How%20to%20quickly%20compile%20FFmpeg%20with%20libx264%20%28x264,%20H.264%29

  Latter needed a following command to get rid of build error, where I spent quite some time with :

  sudo apt-get remove ffmpeg x264 libx264-dev

  So, now I've got to the documentation for HLS : http://ffmpeg.org/ffmpeg-all.html#hls-2

  Trying to run some stuff :

  ffmpeg -i 3.mp4 hls.m3u8

  Error : Unable to find a suitable output format for 'hls.m3u8'

  ffmpeg -i 3.mp4 -hls_time 10 hls.m3u8

  Error :
  Unrecognized option 'hls_time'
  Failed to set value '10' for option 'hls_time'

  Anyway, looks like an options specified in different formats, e.g. 'vbsf' vs 'v:bsf', -vcodec and -v:c, etc. etc. Like there are few alternative versions

  After starting with it some time ago, I feel more pessimistic now like I missed some fundametals. Any Ideas for the things above ?

  Thank you

• C# library for audio resampling that has the same abilities as FFmpeg

  21 avril 2013, par Designation

  I have to use a pure C# solution for resampling audio, which can produce me the exact same results as FFmpeg's audio sampling can.

  FFmpeg first builds some kind of polyphase filter bank, and then uses that for the sampling process (sorry for the vague phrasing, but I'm not too familiar with this topic). According to this brief documentation, the initialization can be customized this way :

  AVResampleContext* av_resample_init(
  
      int     out_rate,
  
      int     in_rate,
  
      int     filter_length,
  
      int     log2_phase_count,
  
      int     linear,
  
      double  cutoff   
  
      )

  The parameters are :

  • out_rate : output sample rate
  • in_rate : input sample rate
  • filter_length : length of each FIR filter in the filterbank relative to the cutoff freq
  • log2_phase_count : log2 of the number of entries in the polyphase filterbank
  • linear : if 1 then the used FIR filter will be linearly interpolated between the 2 closest, if 0 the closest will be used
  • cutoff : cutoff frequency, 1.0 corresponds to half the output sampling rate

  I'd need to use a C# library that is configurable in the same depth. I've been trying to use NAudio (more specifically, its WaveFormatConversionStream class), but there, I could only set the input and output sample rates, so I didn't get the expected results.

  So, is there a C# lib that could resample with the same settings as FFmpeg can ? Or one that has almost all of these settings or similar ones ? Note : I need a C# solution, not a wrapper !