FFmpeg audio API: Difference between revisions
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* Generalized channel mixing (SIMD optimized) - users should be able to set their own channel mixing coefficients. | * 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). | * 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 | * 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. | * Channel reordering - currently there are different orders depending on the codec. | ||
* SIMD optimized interleaving | * SIMD optimized interleaving |
Revision as of 11:09, 12 November 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
- 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?)
Current ideas
Thread with previous discussions in the subject. The thread has several ideas already implemented.
http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/47485/focus=48097