FFmpeg audio API

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 downmixing (SIMD optimized)

Users should be able to set their own downmix coeffs.

• Codec setable downmixing coeffs:

The codec should be able to set and update the coefs during runtime(dca supports that feature, maybe ac3 also).

• Output channel request function (ie, request a specified number of channels, default should be >2 channels mapped to 2 channels).
• Channel reordering, currently there are diffrent orders depending on the codec.
• Simd optimized interleaving
• Allow planer output, (don't duplicate interleaving code in every codec)
• Add support for other bitdepths then 16bits (ie 24/8/32/float)
• Ability to access one channel from a multichannel stream

Features 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