Difference between revisions of "FFmpeg audio API"

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== Current ideas ==
== Current ideas ==


Thread with previous discussions in the subject. The thread has several ideas already implemented.
Threads with previous discussions in the subject:


http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/47485/focus=48097
* http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/47485/focus=48097
** The thread has several ideas already implemented.
* http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-November/038323.html
** Discussion of general ideas and requirements for the new API.

Revision as of 09:13, 3 December 2007

This page is for discussion regarding the reworking of the FFmpeg audio API to accommodate the requirements needed for today's audio codecs.

Features needed

  • Generalized channel mixing (SIMD optimized) - users should be able to set their own channel mixing coefficients.
  • Codec alterable channel mixing coefficients - the codec should be able to set and update the channel mixing coefficients during runtime (DCA supports this feature, maybe AC-3 also).
  • Output channel request function - specify the number of output channels, default should be >2 channels mapped to 2 channels
  • Channel reordering - currently there are different orders depending on the codec.
  • SIMD optimized interleaving
  • Allow planar output - don't duplicate the interleaving code in every codec
  • Support bit depths other than 16-bit - 8-bit/24-bit/32-bit/float
  • Channel selection - ability to access one channel from a multichannel stream

Feature wish list

  • Dolby Pro Logic Surround Sound decoding.
  • Add a better FFT routine. (Would the KISS implementation be a good candidate?)
  • Fixed point MDCT/FFT implementations
  • Custom audio filter support. (Basing it on the video filter API ideas?)
  • Proper API for enabling SIMD optimized code.

Current ideas

Threads with previous discussions in the subject: