1. 15 Mar, 2012 1 commit
    • Yaowu Xu's avatar
      WebM Experimental Codec Branch Snapshot · 6035da54
      Yaowu Xu authored
      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#7a159071)
      
      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
      6035da54
  2. 16 Nov, 2011 1 commit
    • Adrian Grange's avatar
      Added clipping of the buffer level to maximum_buffer_size · 2b1c2990
      Adrian Grange authored
      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
      2b1c2990
  3. 09 Nov, 2011 2 commits
  4. 23 Sep, 2011 1 commit
  5. 22 Sep, 2011 6 commits
  6. 21 Sep, 2011 1 commit
  7. 20 Sep, 2011 9 commits
  8. 19 Sep, 2011 3 commits
    • Stefan Holmer's avatar
      Fix necessary for input partitions iface to match the RTP profile · e529a825
      Stefan Holmer authored
      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
      e529a825
    • Tero Rintaluoma's avatar
      Updated ARMv6 forward transforms to match C · 4c3ad66b
      Tero Rintaluoma authored
      - Updated walsh transform to match C
        (based on Change Id24f3392)
      - Changed fast_fdct4x4 and 8x4 to short_fdct4x4 and 8x4
        correspondingly
      
      Change-Id: I704e862f40e315b0a79997633c7bd9c347166a8e
      4c3ad66b
    • Tero Rintaluoma's avatar
      NEON walsh transform updated to match C · 2a4b2a00
      Tero Rintaluoma authored
      Modified original patch If2f07220885c4c3a0cae0dace34ea0e36124f001
      according to comments. Scheduled code a little bit to prevent some
      interlocks.
      
      Change-Id: I338f02b881098782f82af63d97f042b85e63e902
      2a4b2a00
  9. 17 Sep, 2011 1 commit
  10. 16 Sep, 2011 4 commits
  11. 14 Sep, 2011 2 commits
  12. 13 Sep, 2011 1 commit
    • Scott LaVarnway's avatar
      Fixed encoder crash · 5bc7b3a6
      Scott LaVarnway authored
      caused by the "Removed bmi copy to/from BLOCKD" commit.
      
      Change-Id: I9fae71bdc34c8ecc07bb81cd3ccf498b91ce3ec7
      5bc7b3a6
  13. 31 Aug, 2011 4 commits
  14. 30 Aug, 2011 2 commits
  15. 27 Aug, 2011 1 commit
  16. 26 Aug, 2011 1 commit