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 current code stores pointers to coefficient tables and loads them to
access the tables contents. As these pointers are stored in the code
sections, it means we end up with text relocations. eu-findtextrel will
thus complain about code not compiled with -fpic/-fPIC.
Since the pointers are stored in the code sections, we can actually cheat
and let the assembler generate relative addressing when accessing the
coefficient tables, and just load their location with adr.
Change-Id: Ib74ae2d3f2bab80b29991355f2dbe6955f38f6ae
rvct 4.1 was complaining about vstmia.16, store multiple expects 64 data type.
optimized the implementation.
Change-Id: I0701052cabd685c375637bbc3796ff6d88f5972c
Adds following targets to configure script to support RVCT compilation
without operating system support (for Profiler or bare metal images).
- armv5te-none-rvct
- armv6-none-rvct
- armv7-none-rvct
To strip OS specific parts from the code "os_support"-config was added
to script and CONFIG_OS_SUPPORT flag is used in the code to exclude OS
specific parts such as OS specific includes and function calls for
timers and threads etc. This was done to enable RVCT compilation for
profiling purposes or running the image on bare metal target with
Lauterbach.
Removed separate AREA directives for READONLY data in armv6 and neon
assembly files to fix the RVCT compilation. Otherwise
"ldr <reg>, =label" syntax would have been needed to prevent linker
errors. This syntax is not supported by older gnu assemblers.
Change-Id: I14f4c68529e8c27397502fbc3010a54e505ddb43
This eliminates a large set of warnings exposed by the Mozilla build
system (Use of C++ comments in ISO C90 source, commas at the end of
enum lists, a couple incomplete initializers, and signed/unsigned
comparisons).
It also eliminates many (but not all) of the warnings expose by newer
GCC versions and _FORTIFY_SOURCE (e.g., calling fread and fwrite
without checking the return values).
There are a few spurious warnings left on my system:
../vp8/encoder/encodemb.c:274:9: warning: 'sz' may be used
uninitialized in this function
gcc seems to be unable to figure out that the value shortcut doesn't
change between the two if blocks that test it here.
../vp8/encoder/onyx_if.c:5314:5: warning: comparison of unsigned
expression >= 0 is always true
../vp8/encoder/onyx_if.c:5319:5: warning: comparison of unsigned
expression >= 0 is always true
This is true, so far as it goes, but it's comparing against an enum, and the C
standard does not mandate that enums be unsigned, so the checks can't be
removed.
Change-Id: Iaf689ae3e3d0ddc5ade00faa474debe73b8d3395
ARM NEON has a platform specific version of vp8_recon16x16mb, though
it's just a stub to extract the various parameters from the
MACROBLOCKD struct and pass them to vp8_recon16x16mb_neon(). Using
that function's prototype directly will be a better long term solution,
but it's quite an invasive change.
Change-Id: I04273149e2ade34749e2d09e7edb0c396e1dd620
there were four versions for the regular and
macroblock loopfilters:
horizontal [y|uv]
vertical [y|uv]
this moves all the common code into 2 functions:
vp8_loop_filter_neon
vp8_mbloop_filter_neon
this provides no gain in performance. there's a bit
of jitter, but it trends down ~0.25-0.5%. however,
this is a huge gain maintenance. also, there is the
potential to drop some stack usage in the macroblock
loopfilter.
Change-Id: I91506f07d2f449631ff67ad6f1b3f3be63b81a92
previous implementation compared each set of values to limit and then
&'d them together, requiring a compare and & for each value.
this does the accumulation first, requiring only one compare
Change-Id: Ia5e3a1a50e47699c88470b8c41964f92a0dc1323
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
Jeff Muizelaar posted some changes to the idct/reconstruction c code.
This is the equivalent update for the arm assembly.
This shows a good boost on v6, and a minor boost on neon.
Here are some numbers for highway in qcif, 2641 frames:
HEAD neon: ~161 fps
new neon: ~162 fps
HEAD v6: ~102 fps
new v6: ~106 fps
The following functions have been updated for armv6 and neon:
vp8_dc_only_idct_add
vp8_dequant_idct_add
vp8_dequant_dc_idct_add
Conflicts:
vp8/decoder/arm/armv6/dequantdcidct_v6.asm
vp8/decoder/arm/armv6/dequantidct_v6.asm
Resolved by removing these files. When I rewrote the functions, I also
moved the files to dequant_dc_idct_v6.asm/dequant_idct_v6.asm
Change-Id: Ie3300df824d52474eca1a5134cf22d8b7809a5d4
When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.
Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
