ref: 679e4abdd5f733ab544689ce210b42d37e7ce164
parent: 16ac5a5cde0472fc29719aab7ad0958d1492df43
author: John Koleszar <jkoleszar@google.com>
date: Wed May 15 13:55:08 EDT 2013
Initial version of alpha channel support This is a mostly-working implementation of an extra channel in the bitstream. Configure with --enable-alpha to test. Notable TODOs: - Add extra channel to all mismatch tests, PSNR, SSIM, etc - Configurable subsampling - Variable number of planes (currently always uses all 4) - Loop filtering - Per-plane lossless quantizer - ARNR support This implementation just uses the same contents as the Y channel for the A channel, due to lack of content and general pain in playing back 4 channel content. A later patch will use the actual alpha channel passed in from outside the codec. Change-Id: Ibf81f023b1c570bd84b3064e9b4b8ae52e087592