1. 07 Nov, 2012 1 commit
    • James Zern's avatar
      Fix variance (signed integer) overflow · 98473443
      James Zern authored
      In the variance calculations the difference is summed and later squared.
      When the sum exceeds sqrt(2^31) the value is treated as a negative when
      it is shifted which gives incorrect results.
      
      To fix this we force the multiplication to be unsigned.
      
      The alternative fix is to shift sum down by 4 before multiplying.
      However that will reduce precision.
      
      For 16x16 blocks the maximum sum is 65280 and sqrt(2^31) is 46340 (and
      change).
      
      This change is based on:
      16982342 Missed some variance casts
      fea3556e Fix variance overflow
      
      Change-Id: I2c61856cca9db54b9b81de83b4505ea81a050a0f
      98473443
  2. 06 Nov, 2012 1 commit
  3. 01 Nov, 2012 2 commits
  4. 31 Oct, 2012 3 commits
  5. 29 Oct, 2012 1 commit
    • Yaowu Xu's avatar
      Improves subpixel reference mv evaluation · cc9c637d
      Yaowu Xu authored
      Previously, in evaluating reference motion vectors, MVs are always
      rounded to integer pixel position and SADs are calculated.  This
      commit takes into account the subpixel portion of the mvs, and uses
      bilinear interpolation to produce reference pixel values in subpixel
      postions. In addition, SSE is used in place of SAD. Pixels used are
      16x2 above and 2x16 to the left.
      
      This commmit intends to test the potential of this line of work in
      term of compression improvement, obviously, the change would increase
      decoder complexity significantly.
      
      Test results
      std-hd: 1.738%(avg) 1.779%(glb), 1.663%(ssim)
      derf: 0.472%(avg) 0.477%(glb), 0.418%(ssim)
      
      Change-Id: I3ae1b098f6289df78891134d9a5e4bb2fde87a0b
      cc9c637d
  6. 20 Aug, 2012 1 commit
    • Ronald S. Bultje's avatar
      Superblock coding. · 5d4cffb3
      Ronald S. Bultje authored
      This commit adds a pick_sb_mode() function which selects the best 32x32
      superblock coding mode. Then it selects the best per-MB modes, compares
      the two and encodes that in the bitstream.
      
      The bitstream coding is rather simplistic right now. At the SB level,
      we code a bit to indicate whether this block uses SB-coding (32x32
      prediction) or MB-coding (anything else), and then we follow with the
      actual modes. This could and should be modified in the future, but is
      omitted from this commit because it will likely involve reorganizing
      much more code rather than just adding SB coding, so it's better to let
      that be judged on its own merits.
      
      Gains on derf: about even, YT/HD: +0.75%, STD/HD: +1.5%.
      
      Change-Id: Iae313a7cbd8f75b3c66d04a68b991cb096eaaba6
      5d4cffb3
  7. 08 Aug, 2012 1 commit
    • Deb Mukherjee's avatar
      Merging in the sixteenth subpel uv experiment · 7d065653
      Deb Mukherjee authored
      Merges this experiment in to make it easier to run tests on
      filter precision, vectorized implementation etc.
      
      Also removes an experimental filter.
      
      Change-Id: I1e8706bb6d4fc469815123939e9c6e0b5ae945cd
      7d065653
  8. 17 Jul, 2012 1 commit
  9. 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
  10. 23 Feb, 2012 1 commit
    • Deb Mukherjee's avatar
      Supporting high precision 1/8-pel motion vectors · 18e90d74
      Deb Mukherjee authored
      This is the initial patch for supporting 1/8th pel
      motion. Currently if we configure with enable-high-precision-mv,
      all motion vectors would default to 1/8 pel. Encode and
      decode syncs fine with the current code. In the next phase
      the code will be refactored so that we can choose the 1/8
      pel mode adaptively at a frame/segment/mb level.
      
      Derf results:
      http://www.corp.google.com/~debargha/vp8_results/enhinterp_hpmv.html
      (about 0.83% better than 8-tap interpoaltion)
      
      Patch 3: Rebased. Also adding 1/16th pel interpolation for U and V
      
      Patch 4: HD results.
      http://www.corp.google.com/~debargha/vp8_results/enhinterp_hd_hpmv.html
      Seems impressive (unless I am doing something wrong).
      
      Patch 5: Added mmx/sse for bilateral filtering, as well as enforced
      use of c-versions of subpel filters with 8-taps and 1/16th pel;
      Also redesigned the 8-tap filters to reduce the cut-off in order to
      introduce a denoising effect. There is a new configure option
      sixteenth-subpel-uv which will use 1/16 th pel interpolation for
      uv, if the motion vectors have 1/8 pel accuracy.
      
      With the fixes the results are promising on the derf set. The enhanced
      interpolation option with 8-taps alone gives 3% improvement over thei
      derf set:
      http://www.corp.google.com/~debargha/vp8_results/enhinterpn.html
      
      Results on high precision mv and on the hd set are to follow.
      
      Patch 6: Adding a missing condition for CONFIG_SIXTEENTH_SUBPEL_UV in
      vp8/common/x86/x86_systemdependent.c
      
      Patch 7: Cleaning up various debug messages.
      
      Patch 8: Merge conflict
      
      Change-Id: I5b1d844457aefd7414a9e4e0e06c6ed38fd8cc04
      18e90d74
  11. 06 Jun, 2011 1 commit
    • Yaowu Xu's avatar
      remove redundant functions · d4700731
      Yaowu Xu authored
      The encoder defined about 4 set of similar functions to calculate sum,
      variance or sse or a combination of them. This commit removed one set
      of these functions, get8x8var and get16x16var, where calls to the later
      function are replaced with var16x16 by using the fact on a 16x16 MB:
          variance == sse - sum*sum/256
      
      Change-Id: I803eabd1fb3ab177780a40338cbd596dffaed267
      d4700731
  12. 18 Mar, 2011 1 commit
    • John Koleszar's avatar
      Increase static linkage, remove unused functions · 429dc676
      John Koleszar authored
      A large number of functions were defined with external linkage, even
      though they were only used from within one file. This patch changes
      their linkage to static and removes the vp8_ prefix from their names,
      which should make it more obvious to the reader that the function is
      contained within the current translation unit. Functions that were
      not referenced were removed.
      
      These symbols were identified by:
      
        $ nm -A libvpx.a | sort -k3 | uniq -c -f2 | grep ' [A-Z] ' \
          | sort | grep '^ *1 '
      
      Change-Id: I59609f58ab65312012c047036ae1e0634f795779
      429dc676
  13. 27 Oct, 2010 2 commits
    • John Koleszar's avatar
      Fix half-pixel variance RTCD functions · a0ae3682
      John Koleszar authored
      This patch fixes the system dependent entries for the half-pixel
      variance functions in both the RTCD and non-RTCD cases:
      
        - The generic C versions of these functions are now correct.
          Before all three cases called the hv code.
      
        - Wire up the ARM functions in RTCD mode
      
        - Created stubs for x86 to call the optimized subpixel functions
          with the correct parameters, rather than falling back to C
          code.
      
      Change-Id: I1d937d074d929e0eb93aacb1232cc5e0ad1c6184
      a0ae3682
    • John Koleszar's avatar
      Add half-pixel variance RTCD functions · 209d82ad
      John Koleszar authored
      NEON has optimized 16x16 half-pixel variance functions, but they
      were not part of the RTCD framework. Add these functions to RTCD,
      so that other platforms can make use of this optimization in the
      future and special-case ARM code can be removed.
      
      A number of functions were taking two variance functions as
      parameters. These functions were changed to take a single
      parameter, a pointer to a struct containing all the variance
      functions for that block size. This provides additional flexibility
      for calling additional variance functions (the half-pixel special
      case, for example) and by initializing the table for all block sizes,
      we don't have to construct this function pointer table for each
      macroblock.
      
      Change-Id: I78289ff36b2715f9a7aa04d5f6fbe3d23acdc29c
      209d82ad
  14. 12 Oct, 2010 1 commit
  15. 09 Sep, 2010 1 commit
  16. 18 Jun, 2010 1 commit
    • John Koleszar's avatar
      cosmetics: trim trailing whitespace · 94c52e4d
      John Koleszar authored
      When the license headers were updated, they accidentally contained
      trailing whitespace, so unfortunately we have to touch all the files
      again.
      
      Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
      94c52e4d
  17. 04 Jun, 2010 1 commit
  18. 18 May, 2010 1 commit