this was never fleshed out in the context of VP8, for which it was
added. for VP9 it has no meaning.
Change-Id: Iba2ecc026d9e947067b96690245d337e51e26eff
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
Make framebuffer allocations according to the chroma subsamping
factors in use. A bit is placed in the raw part of the frame header for
each of the two subsampling factors. This will be moved in a future
commit to make them part of the TBD feature set bits, probably only set
on keyframes, etc.
Change-Id: I59ed38d3a3c0d4af3c7c277617de28d04a001853
This is like VP8_COPY_REFERENCE, but returns a pointer to the reference
frame rather than a copy of it. This is useful when the application
doesn't know what the size of the reference is, as is the case when
scaling is in effect.
Change-Id: I63667109f65510364d0e397ebe56217140772085
