This commit adds lossless compression capability to the experimental
branch. The lossless experiment can be enabled using --enable-lossless
in configure. When the experiment is enabled, the encoder will use
lossless compression mode by command line option --lossless, and the
decoder automatically recognizes a losslessly encoded clip and decodes
accordingly.
To achieve the lossless coding, this commit has changed the following:
1. To encode at lossless mode, encoder forces the use of unit
quantizer, i.e, Q 0, where effective quantization is 1. Encoder also
disables the usage of 8x8 transform and allows only 4x4 transform;
2. At Q 0, the first order 4x4 DCT/IDCT have been switched over
to a pair of forward and inverse Walsh-Hadamard Transform
(http://goo.gl/EIsfy), with proper scaling applied to match the range
of the original 4x4 DCT/IDCT pair;
3. At Q 0, the second order remains to use the previous
walsh-hadamard transform pair. However, to maintain the reversibility
in second order transform at Q 0, scaling down is applied to first
order DC coefficients prior to forward transform, and scaling up is
applied to the second order output prior to quantization. Symmetric
upscaling and downscaling are added around inverse second order
transform;
4. At lossless mode, encoder also disables a number of minor
features to ensure no loss is introduced, these features includes:
a. Trellis quantization optimization
b. Loop filtering
c. Aggressive zero-binning, rounding and zero-bin boosting
d. Mode based zero-bin boosting
Lossless coding test was performed on all clips within the derf set,
to verify that the commit has achieved lossless compression for all
clips. The average compression ratio is around 2.57 to 1.
(http://goo.gl/dEShs)
Change-Id: Ia3aba7dd09df40dd590f93b9aba134defbc64e34
For now the interface elements have been left in place
to make sure existing parameter files work but parameters
relating to drop frame wont do anything.
Change-Id: I579ee614726387381c546845dac4bc03c74c6a07
Adding support in the encoder for generating
independent residual partitions by forcing
equal probabilities over the prev coef entropy
contexts.
Change-Id: I402f5c353255f3ca20eae2620af739f6a498cd21
This patch changes the rc_undershoot_pct and rc_overshoot_pct controls
to set the "aggressiveness" of rate adaptation, by limiting the
amount of difference between the target buffer level and the actual
buffer level which is applied to the target frame rate for this frame.
This patch was initially provided by arosenberg at logitech.com as
an attachment to issue #270. It was modified to separate these controls
from the other unrelated modifications in that patch, as well as to
use the pre-existing variables rather than introducing new ones.
Change-Id: Id542e3f5667dd92d857d5eabf29878f2fd730a62
The merge includes hooks to for CQ mode and other code
changes merged from the test branch.
CQ mode attempts to maintain a more stable quantizer within a clip
whilst also trying to adhere to a guidline maximum bitrate.
The existing target data rate parameter is used to specify the
guideline maximum bitrate.
A new parameter allows the user to specify a target CQ level.
For normal (non kf/gf/arf) frames, the quantizer will not drop BELOW the
user specified value (0-63). However, in some cases the encoder may
choose to impose a target CQ that is above that specified by the user,
if it estimates that consistent use of the target value is not compatible
with guideline maximum bitrate.
Change-Id: I2221f9eecae8cc3c431d36caf83503941b25e4c1
Add a new encoder control, VP8E_SET_TUNING, to allow the application
to inform the encoder that the material will benefit from certain
tuning. Expose this control as the --tune option to vpxenc. The args
helper is expanded to support enumerated arguments by name or value.
Two tunings are provided by this patch, PSNR (default) and SSIM.
Activity masking is made dependent on setting --tune=ssim, as the
current implementation hurts speed (10%) and PSNR (2.7% avg,
10% peak) too much for it to be a default yet.
Change-Id: I110d969381c4805347ff5a0ffaf1a14ca1965257
Debugging in postproc needs more flags to allow for specific
block types to be turned on or off in the visualizations.
Must be enabled with --enable-postproc-visualizer during
configuration time.
Change-Id: Ia74f357ddc3ad4fb8082afd3a64f62384e4fcb2d
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.
Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
This renames the vpx_codec/ directory to vpx/, to allow applications
to more consistently reference these includes with the vpx/ prefix.
This allows the includes to be installed in /usr/local/include/vpx
rather than polluting the system includes directory with an
excessive number of includes.
Change-Id: I7b0652a20543d93f38f421c60b0bbccde4d61b4f
