aomedia /
aom /
9ac5508f32072131b6405875bbc0e05b78471c58 Add EC_ADAPT experiment for symbol-adaptive entropy coding.
This experiment performs symbol-by-symbol statistics
adaptation for non-binary symbols. It requires DAALA_EC or
RANS and ANS to be enabled. The adaptation is currently
based on a simple recursive filter and is taken from
Daala. It has an adaptation rate dependent on alphabet size,
taken from Daala. It applies wherever non-binary symbols
are encoded using Cumulative Probability Functions rather
than trees.
Where symbols are adapted, forward updates in the compressed
header are removed.
In the case of RANS coefficient token values are adapted,
with the exception of the zero token which remains a
binary symbol. In the case of DAALA_EC other values
such as inter and intra modes are adapted as CDFs are
provided in those cases.
The experiment is configured with:
./configure --enable-experimental --enable-daala-ec --enable-ec-adapt
or
./configure --enable-experimental --enable-ans --enable-rans \
--enable-ec-adapt
EC_ADAPT is not currently compatible with tiles.
BDR results on Objective-1-fast give a small loss:
PSNR YCbCr: 0.51% 0.49% 0.48%
PSNRHVS: 0.50%
SSIM: 0.50%
MSSSIM: 0.51%
CIEDE2000: 0.50%
Change-Id: I3888718e42616f3fd87144de7f125228446ac984
13 files changed
