This is a code snapshot of experimental work currently ongoing for a
next-generation codec.
The codebase has been cut down considerably from the libvpx baseline.
For example, we are currently only supporting VBR 2-pass rate control
and have removed most of the code relating to coding speed, threading,
error resilience, partitions and various other features. This is in
part to make the codebase easier to work on and experiment with, but
also because we want to have an open discussion about how the bitstream
will be structured and partitioned and not have that conversation
constrained by past work.
Our basic working pattern has been to initially encapsulate experiments
using configure options linked to #IF CONFIG_XXX statements in the
code. Once experiments have matured and we are reasonably happy that
they give benefit and can be merged without breaking other experiments,
we remove the conditional compile statements and merge them in.
Current changes include:
* Temporal coding experiment for segments (though still only 4 max, it
will likely be increased).
* Segment feature experiment - to allow various bits of information to
be coded at the segment level. Features tested so far include mode
and reference frame information, limiting end of block offset and
transform size, alongside Q and loop filter parameters, but this set
is very fluid.
* Support for 8x8 transform - 8x8 dct with 2nd order 2x2 haar is used
in MBs using 16x16 prediction modes within inter frames.
* Compound prediction (combination of signals from existing predictors
to create a new predictor).
* 8 tap interpolation filters and 1/8th pel motion vectors.
* Loop filter modifications.
* Various entropy modifications and changes to how entropy contexts and
updates are handled.
* Extended quantizer range matched to transform precision improvements.
There are also ongoing further experiments that we hope to merge in the
near future: For example, coding of motion and other aspects of the
prediction signal to better support larger image formats, use of larger
block sizes (e.g. 32x32 and up) and lossless non-transform based coding
options (especially for key frames). It is our hope that we will be
able to make regular updates and we will warmly welcome community
contributions.
Please be warned that, at this stage, the codebase is currently slower
than VP8 stable branch as most new code has not been optimized, and
even the 'C' has been deliberately written to be simple and obvious,
not fast.
The following graphs have the initial test results, numbers in the
tables measure the compression improvement in terms of percentage. The
build has the following optional experiments configured:
--enable-experimental --enable-enhanced_interp --enable-uvintra
--enable-high_precision_mv --enable-sixteenth_subpel_uv
CIF Size clips:
http://getwebm.org/tmp/cif/
HD size clips:
http://getwebm.org/tmp/hd/
(stable_20120309 represents encoding results of WebM master branch
build as of commit#7a15907)
They were encoded using the following encode parameters:
--good --cpu-used=0 -t 0 --lag-in-frames=25 --min-q=0 --max-q=63
--end-usage=0 --auto-alt-ref=1 -p 2 --pass=2 --kf-max-dist=9999
--kf-min-dist=0 --drop-frame=0 --static-thresh=0 --bias-pct=50
--minsection-pct=0 --maxsection-pct=800 --sharpness=0
--arnr-maxframes=7 --arnr-strength=3(for HD,6 for CIF)
--arnr-type=3
Change-Id: I5c62ed09cfff5815a2bb34e7820d6a810c23183c
The buffer level was not being capped at the maximum decode
buffer size specified by the user.
In CBR mode this resulted in large files being generated
immediately after a dramatic reduction in the data rate
target. This fix should prevent this from happening.
Change-Id: Iaf01c9fb037cf51515217a5834d6ee4fbb0cb853
To avoid a dependency on vpx_version.h, call the vpx_codec_version_str()
function and build up the string manually.
Change-Id: Ie650e9b8f2aaaffaa31da5e9ef3b566b972321b4
Make sure that this header is listed as one of the sources, so that it
will be installed if necessary.
Change-Id: I2427e494488126b179151dc21043c1e2c8ba5991
- Removed fast_fdct4x4_neon and fast_fdct8x4_neon
- Uses now short_fdct4x4 and short_fdct8x4
- Gives ~1-2% speed-up on Cortex-A8/A9
Change-Id: Ib62f2cb2080ae719f8fa1d518a3a5e71278a41ec
Rd and Rm registers should be different in 'mul'. This register
combination results in unpredictable behaviour. GCC will give
a warning and RVCT an error in this case.
Restriction applies only to armv5 targets and not for armv6 and above.
Change-Id: I378d17c51e1f16a6820814fbed43e115aaabb03e
These changes fixes a glitch between the RTP profile and the input
partitions interface. Since there's no way for the user to know the
actual number of partitions, the decoder have to read the
multi_token_paritition bits also when input partitions mode is
enabled.
Included are also a couple of fixes for issues with independent
partitions and uninitialized memory reads.
Change-Id: I6f93b15287d291169ed681898ed3fbcc5dc81837
- Updated walsh transform to match C
(based on Change Id24f3392)
- Changed fast_fdct4x4 and 8x4 to short_fdct4x4 and 8x4
correspondingly
Change-Id: I704e862f40e315b0a79997633c7bd9c347166a8e
Modified original patch If2f07220885c4c3a0cae0dace34ea0e36124f001
according to comments. Scheduled code a little bit to prevent some
interlocks.
Change-Id: I338f02b881098782f82af63d97f042b85e63e902
In the "Removed bmi copy to/from BLOCKD" commit, the copy
to the bmi in BLOCKD was eliminated. The clamp_mvs() used
the bmi in BLOCKD, which now contains incorrect values. This
patch fixes this problem.
Change-Id: I8eca1eaf4015052b0b63e90876f7ad321aba7cff
vp8_update_zbin_extra() is called all the time even though the fast
quantizer doesn't use it. Skip this call if fast quantizer is used.
Change-Id: Ia711c38431930cc2486cf59b8466060ef0e9d9db
This change makes sure that no key frame recoding in real-time mode
even if CONFIG_REALTIME_ONLY is not configured.
Change-Id: Ifc34141f3217a6bb63cc087d78b111fadb35eec2
for SPLITMV and B_PRED modes. Modified code to use the bmi
found in mode_info_context instead of BLOCKD. On the decode
side, the uvmvs are calculated only when required, instead of
every macroblock. This is WIP. (bmi should eventually be
removed from BLOCKD)
Small performance gains noticed for RT encodes and decodes.(VGA)
Change-Id: I2ed7f0fd5ca733655df684aa82da575c77a973e7
Prepend idct function names with vp8_
so that under profiling they show up
associated with libvpx.
Change-Id: I4fe357b50236cb7730a4cc00164c0a3487a1d8b4
The data that the simple horizontal loopfilter reads is aligned, treat
it accordingly.
For the vertical, we only use the bottom 4 bytes, so don't read in 16
(and incur the penalty for unaligned access).
This shows a small improvement on older processors which have a
significant penalty for unaligned reads.
postproc_mmx.c is unused
Change-Id: I87b29bbc0c3b19ee1ca1de3c4f47332a53087b3d
Prepend . to local labels in assembly code. This
allows non unique labels within a file. Also
makes profiling information more informative
by keeping the function name with the loop name.
Change-Id: I7a983cb3a5ba2413d5dafd0a37936b268fb9e37f
