1. 27 Jun, 2012 1 commit
    • Adrian Grange's avatar
      Added Prediction Filter to Mode Selection · bbc926dc
      Adrian Grange authored
      Added the ability to optionally filter the prediction data
      when inter modes are selected (excludes SPLITMV, for now).
      
      The mode selection loop considers both the filtered and
      non-filtered prediction data when choosing mode. The filter
      can be turned on/off at the frame-level, or signaled for
      each MB.
      
      Change-Id: I1b783c71d95a361ab36c761b07e8a6b06bc36822
      bbc926dc
  2. 26 Jun, 2012 1 commit
    • Deb Mukherjee's avatar
      Continued adaptive entropy coding · f3dff402
      Deb Mukherjee authored
      Incorporates mv_ref, mbsplit and second_mv into the adaptive
      entropy framework. The mv_ref framework has been modified from
      before.
      
      Adds some clean-ups and fixes.
      
      Results with the adaptive entropy experiment are currently up by
      +1.93% on derf; +2.33% std-hd and +1.87% yt-hd.
      
      Fixed a nasty intermittent bug.
      
      Change-Id: I4b1ac9f9483b48432597595195bfec05f31d1e39
      f3dff402
  3. 19 Jun, 2012 1 commit
  4. 15 Jun, 2012 1 commit
    • Deb Mukherjee's avatar
      Adaptive entropy coding of coefficients, modes, mv. · 1fe85a35
      Deb Mukherjee authored
      This patch incorporates adaptive entropy coding of coefficient tokens,
      and mode/mv information based on distributions encountered in a frame.
      Specifically, there is an initial forward update to the probabilities
      in the bitstream as before for coding the symbols in the frame, however
      at the end of decoding each frame, the forward update to the
      probabilities is reverted and instead the probabilities are updated
      towards the actual distributions encountered within the frame.
      The amount of update is weighted by the number of hits within each
      context.
      
      Results on derf/hd/std-hd are all up by 1.6%.
      
      On derf, the most of the gains come from coefficients, however for the
      hd and std-hd sets, the most of the gains come from the mode/mv
      information updates.
      
      Change-Id: I708c0e11fdacafee04940fe7ae159ba6844005fd
      1fe85a35
  5. 15 May, 2012 1 commit
  6. 20 Apr, 2012 1 commit
    • Yaowu Xu's avatar
      change to allow 8x8 transform always · ade43d91
      Yaowu Xu authored
      This commit changed to enable the usage 8x8 transform for all frame
      type, all resolution and all quantizer range. This has an overall
      benefit .2% to .3% in term of compression, but more importantly,
      the difficult clips benefits much more, up to 2% to 3% on clips
      like football, harbour and so on.
      
      We observed some weird humps on very high end on a couple of youtube
      clips, but have determined the underly cause was the aggressive zbin
      having an effect of lowering rate with lower quality, which have
      an impact on slide show clips around 60DB.
      
      The commit does not change the association between prediction mode
      and transform size.
      
      Change-Id: I33043bdce6207528ae00b4a4b26d8ff63cfea1f4
      ade43d91
  7. 17 Apr, 2012 1 commit
    • Yaowu Xu's avatar
      Added intra mode probabilites into coding_context · 31afc770
      Yaowu Xu authored
      These contexts need to be saved and restored for recode, otherwise
      encoder/decoder mismatch happens for some clips (eg._mobcal 720p)
      
      Change-Id: Ic65cfa0bf56ed0472ecab962ce31394d59d344bf
      31afc770
  8. 11 Apr, 2012 1 commit
    • Paul Wilkins's avatar
      Refactoring of encode loop and bitstream packing · 13c6d1a8
      Paul Wilkins authored
      Some code re-factored / moved to allow the main
      pack operation inside the recode loop so  that the
      size estimate is accurate.
      
      Deletion of some redundant code relating to one pass.
      
      Aproximate improvement over March 27 code base:
      Derf 0.0%, YT 0.5%, YThd 0.3% Std_hd 0.25%
      
      Change-Id: Id2d071794ab44f0b52935f6fcdb5733d09a6bb86
      13c6d1a8
  9. 21 Mar, 2012 1 commit
    • Yaowu Xu's avatar
      enable 8x8 transform for MBs in intra frames · 2823173e
      Yaowu Xu authored
      When ac_yquant>171, a key frame is enabled to use 8x8 transform. In
      such case, MBs with DC_PRED or TM_PRED are selected to use T8x8. This
      change helped the full STD-HD set by ~.1% or so, which is reasonable
      considering how often key frame occurs in these encodings.
      
      Change-Id: Id17009ef6327252177b19e6bf0d6628827febaf1
      2823173e
  10. 15 Mar, 2012 1 commit
    • Yaowu Xu's avatar
      fixed a bug of context overwritten by key frame recoding · ea43ba4a
      Yaowu Xu authored
      The recoding loop save and restore frame coding context for recodes.
      However in recoding of key frames, some of the coding context saved
      was stale from last encoded inter frame. The save/restore sometimes
      overwrites the re-inintialized coding context with saved context
      from last frame, resulting in encoder/decoder mismatch
      
      Change-Id: I354ae2f71074d142602d51d06544c05a2462caaf
      ea43ba4a
  11. 01 Mar, 2012 2 commits
  12. 28 Feb, 2012 2 commits
    • Deb Mukherjee's avatar
      Initial refactoring of high_precision mv code. · 3e1cad9c
      Deb Mukherjee authored
      This is the first patch for refactoring of the code related to
      high-precision mv, so that 1/4 and 1/8 pel motion vectors can
      co-exist in the same bit-stream by use of a frame level flag.
      The current patch works fine for only use of 1/4th and
      only use of 1/8th pel mv, but there are some issues with the
      mode switching in between. Subsequent patches on this change Id
      will fix the remaining issues.
      
      Patch 2: Adds fixes to make sure that multiple mv precisions can
      co-exist in the bit-stream. Frame level switching has been tested
      to work correctly.
      
      Patch 3: Fixes lines exceeding 80 char
      
      Patch 4:
      http://www.corp.google.com/~debargha/vp8_results/enhinterp.html
      
      Results on derf after ssse3 bugfix, compared to everything
      enabled but the 8-tap, 1/8-subpel and 1/16-subpel uv. Overall the
      gains are about 3% now. Hopefully there are no more bugs lingering.
      Apparently the sse3 bug affected the quartel subpel results more than
      the eighth pel ones (which is understandabale because one bad predictor
      due to the bug, matters less if there are a lot more subpel options
      available as in the 1/8 subpel case).
      The results in the 4th column correspond to the current settings.
      The first two columns correspond to two settings of adaptive switching
      of the 1/4 or 1/8 subpel mode based on initial Q estimate. These
      do not work as good as just using 1/8 all the time yet.
      
      Change-Id: I3ef392ad338329f4d68a85257a49f2b14f3af472
      3e1cad9c
    • Yaowu Xu's avatar
      Try to enable 8x8 tranform for smaller resolution · 42891098
      Yaowu Xu authored
      The commit overall on derf test is break even to very slightly positive
      comparing to all 4x4 transform.
      
      Change-Id: I2a7c19599aa54c2d3a5b35db0dc891ba8a6a2b26
      42891098
  13. 26 Feb, 2012 1 commit
    • Paul Wilkins's avatar
      Code Cleanup. · 646e6221
      Paul Wilkins authored
      Removal of error_resilient_mode features.
      The interface has been left in place but does nothing.
      
      Change-Id: I2407863bd0d3c98407354507423ca48d29f63b17
      646e6221
  14. 25 Feb, 2012 1 commit
    • Paul Wilkins's avatar
      Removal of temporal re sampling code. · 80b873e3
      Paul Wilkins authored
      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
      80b873e3
  15. 24 Feb, 2012 1 commit
  16. 17 Feb, 2012 1 commit
    • Paul Wilkins's avatar
      Code base simplification. · 4cfb8ed4
      Paul Wilkins authored
      Removal of most code to do with 1 pass.
      Removal of cyclic refresh code.
      
      Change-Id: I74971082bc19dd76e795d4d2e781a0424cec5c8c
      4cfb8ed4
  17. 16 Feb, 2012 1 commit
    • Paul Wilkins's avatar
      Code simplification · 79d330d7
      Paul Wilkins authored
      Removal of the pickinter.c and .h files and calls to this
      code.
      
      Removal of some code relating to real time and one pass
      settings  though there is more to be done in this regard.
      
      However,  vp8_set_speed_features() now
      only supports modes 0 and 1 and speeds up to 3
      so rd should always be set.
      
      Change-Id: I62c0c1b6154ab499785baef310536080e87bc4d8
      79d330d7
  18. 10 Feb, 2012 1 commit
    • Ronald S. Bultje's avatar
      Improved coding using 8x8 transform · f64725a0
      Ronald S. Bultje authored
      In summary, this commit encompasses a series of changes in attempt to
      improve the 8x8 transform based coding to help overall compression
      quality, please refer to the detailed commit history below for what
      are the rationale underly the series of changes:
      
      a. A frame level flag to indicate if 8x8 transform is used at all.
      b. 8x8 transform is not used for key frames and small image size.
      c. On inter coded frame, macroblocks using modes B_PRED, SPLIT_MV
      and I8X8_PRED are forced to using 4x4 transform based coding, the
      rest uses 8x8 transform based coding.
      d. Encoder and decoder has the same assumption on the relationship
      between prediction modes and transform size, therefore no signaling
      is encoded in bitstream.
      e. Mode decision process now calculate the rate and distortion scores
      using their respective transforms.
      
      Overall test results:
      1. HD set
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/HD_t8x8_20120206.html
      (avg psnr: 3.09% glb psnr: 3.22%, ssim: 3.90%)
      2. Cif set:
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/cif_t8x8_20120206.html
      (avg psnr: -0.03%, glb psnr: -0.02%, ssim: -0.04%)
      It should be noted here, as 8x8 transform coding itself is disabled
      for cif size clips, the 0.03% loss is purely from the 1 bit/frame
      flag overhead on if 8x8 transform is used or not for the frame.
      
      ---patch history for future reference---
      Patch 1:
      this commit tries to select transform size based on macroblock
      prediction mode. If the size of a prediction mode is 16x16, then
      the macroblock is forced to use 8x8 transform. If the prediction
      mode is B_PRED, SPLITMV or I8X8_PRED, then the macroblock is forced
      to use 4x4 transform. Tests on the following HD clips showed mixed
      results: (all hd clips only used first 100 frames in the test)
      
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/hdmodebased8x8.html
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/hdmodebased8x8_log.html
      
      while the results are mixed and overall negative, it is interesting to
      see 8x8 helped a few of the clips.
      
      Patch 2:
      this patch tries to hard-wire selection of transform size based on
      prediction modes without using segmentation to signal the transform size.
      encoder and decoder both takes the same assumption that all macroblocks
      use 8x8 transform except when prediciton mode is B_PRED, I8X8_PRED or
      SPLITMV. Test results are as follows:
      
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/cifmodebase8x8_0125.html
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/hdmodebased8x8_0125log.html
      
      Interestingly, by removing the overhead or coding the segmentation, the
      results on this limited HD set have turn positive on average.
      
      Patch 3:
      this patch disabled the usage of 8x8 transform on key frames, and kept the
      logic from patch 2 for inter frames only. test results on HD set turned
      decidedly positive with 8x8 transform enabled on inter frame with 16x16
      prediction modes: (avg psnr: .81% glb psnr: .82 ssim: .55%)
      
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/hdintermode8x8_0125.html
      results on cif set still negative overall
      
      Patch 4:
      continued from last patch, but now in mode decision process, the rate and
      distortion estimates are computed based on 8x8 transform results for MBs
      with modes associated with 8x8 transform. This patch also fixed a problem
      related to segment based eob coding when 8x8 transform is used. The patch
      significantly improved the results on HD clips:
      
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/hd8x8RDintermode.html
      (avg psnr: 2.70% glb psnr: 2.76% ssim: 3.34%)
      results on cif also improved, though they are still negative compared to
      baseline that uses 4x4 transform only:
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/cif8x8RDintermode.html
      (avg psnr: -.78% glb psnr: -.86% ssim: -.19%)
      
      Patch 5:
      This patch does 3 things:
      a. a bunch of decoder bug fixes, encodings and decodings were verified
      to have matched recon buffer on a number of encodes on cif size mobile and
      hd version of _pedestrian.
      b. the patch further improved the rate distortion calculation of MBS that
      use 8x8 transform. This provided some further gain on compression.
      c. the patch also got the experimental work SEG_LVL_EOB to work with 8x8
      transformed macroblock, test results indicates it improves the cif set
      but hurt the HD set slightly.
      
      Tests results on HD clips:
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/HD_t8x8_20120201.html
      (avg psnr: 3.19% glb psnr: 3.30% ssim: 3.93%)
      
      Test results on cif clips:
      http://www.corp.google.com/~yaowu/no_crawl/t8x8/cif_t8x8_20120201.html
      (avg psnr: -.47% glb psnr: -.51% ssim: +.28%)
      
      Patch 6:
      Added a frame level flag to indicate if 8x8 transform is allowed at all.
      temporarily the decision is based on frame size, can be optimized later
      one. This get the cif results to basically unchanged, with one bit per
      frame overhead on both cif and hd clips.
      
      Patch 8:
      Rebase and Merge to head by PGW.
      Fixed some suspect 4s that look like hey should be 64s in regard
      to segmented EOB. Perhaps #defines would be bette.
      Bulit and tested without T8x8 enabled and produces unchanged
      output.
      
      Patch 9:
      Corrected misalligned code/decode of "txfm_mode" bit.
      Limited testing for correct encode and decode with
      T8x8 configured on derf clips.
      
      Change-Id: I156e1405d25f81579d579dff8ab9af53944ec49c
      f64725a0
  19. 09 Feb, 2012 1 commit
  20. 06 Feb, 2012 1 commit
    • Paul Wilkins's avatar
      Merged NEWNEAR experiment · 9c9300f5
      Paul Wilkins authored
      This commit merges the NEWNEAR experiment such that it
      is effectively always on.
      
      The fact that there were changes in the threading code again
      highlights the need to strip out such features during the
      bitstream development phase as trying to maintain this code
      (especially as it is not being tested) slows the development cycle.
      
      Change-Id: I8b34950a1333231ced9928aa11cd6d6459984b65
      9c9300f5
  21. 17 Jan, 2012 1 commit
    • Paul Wilkins's avatar
      Rate control on static scenes plus Y2dc delta Q fix. · cf561bad
      Paul Wilkins authored
      A problem can arise on static clips with force key frames where
      attempts to avoid popping lead to a progressive reduction in key
      frame Q that ultimately may lead to unexpected overspend against
      the  rate target.
      
      The changes in this patch help to insure that in such clips the
      quality of the key frames across the clip is more uniform (rather
      than starting bad and getting better - especially at low target rates).
      
      This patch also includes a fix that removes a delta on the Y2DC
      when the baseline q index < 4 as this is no longer needed.
      
      There is also a fix to try and prevent repeat single step Q adjustment in
      the recode loop leading to lots of recodes, especially where the use
      of forced skips as part of segmentation has made the impact of Q on
      the number of bits generated much smaller.
      
      Patch 2: Amend "last_boosted_qindex" calculation for arf overlay frames.
      
      Change-Id: Ia1feeb79ed8ed014e4239994fcf5e58e68fd9459
      cf561bad
  22. 12 Dec, 2011 1 commit
    • Paul Wilkins's avatar
      QINDEX_RANGE fixed tables. · ae9023a3
      Paul Wilkins authored
      Removed a couple more fixed tables for the extended quantizer experiment
      that depend on QINDEX_RANGE.
      
      Change-Id: I2c15ffc7488c2a2b8d6504e2c4b6b2339799d117
      ae9023a3
  23. 09 Dec, 2011 1 commit
  24. 07 Dec, 2011 3 commits
    • Yaowu Xu's avatar
      Removed #if CONFIG_MULCONTEXT · b70f23ca
      Yaowu Xu authored
      This commit removed the macro CONFIG_MULCONTEXT, which was used to
      indicate the experiment code for using separate context for altref
      and normal frames. This commit made the change fully merged in.
      
      Change-Id: I525f927f68e2365d37b340ef23b836a136a4f70b
      b70f23ca
    • Yaowu Xu's avatar
      made vp8_mode_context adaptive · 76feb965
      Yaowu Xu authored
      vp8_mode_contexts[] is an entropy table used to code inter mode
      choices. It was a fixed constant table. This commit made the entropy
      context adaptive. Tests on derf set showed very good consistent gains
      on all metrics: avg psnr .47%, overall psnr .46% and ssim .40%.
      
      http://www.corp.google.com/~yaowu/no_crawl/newModeContext.html
      
      Change-Id: Ia62b14485c948e2b74586118619c5eb2068b43b2
      76feb965
    • Yaowu Xu's avatar
      fixed a crash when MODE_STATS is enabled · b1823a7d
      Yaowu Xu authored
      The MODE_STATS macro was used to #ifdef around code for mode entropy
      stats collection, this commit fixed a crash when MODE_STATS is on.
      The commit also changed a number of array definitions to use defined
      macros instead of hard-coded numbers.
      
      Change-Id: I114592f53a1e44e31e455f5725f036ae6168735a
      b1823a7d
  25. 06 Dec, 2011 1 commit
    • Paul Wilkins's avatar
      Some further QIndex issues with extended Q · b4ad9b5d
      Paul Wilkins authored
      Resolved or factored out some further issues with Q index.
      Put in a 3rd order polynomial instead of less accurate power function
      as the best fit on gf and kf boost adjustment.
      Added avg_q value to use instead of ni_av_qi.
      Compute segment delta Q values based on avg_q.
      Fixed bug in adjust_maxq_qrange().
      
      The extended range Q on the derf set, using standard data rates
      (which do not extend high enough to get big benefits) still show
      a shortfall of between 0.5 and 1% though so there would appear to
      be further issues that need to be tracked down.
      
      Change-Id: Icfd49b9f401906ba487ef1bef7d397048295d959
      b4ad9b5d
  26. 02 Dec, 2011 1 commit
    • Yaowu Xu's avatar
      added separate entropy context for alt_ref · acf5d20c
      Yaowu Xu authored
      This commit added code to keep track of separate entropy contexts for
      normal frames and alt ref frames. The underly assumption was that the
      two type of frames have different entropy characteristics given they
      typically have quite different quantization levels. By keeping entropy
      contexts separate, it helps the entropy context distribution to be more
      closely adapted to each frame type.
      
      Tests on derf set showed a good and very consistent gain on all clips
      on all metrics, avg psnr: 0.89%, overall psnr: 0.84% and ssim 0.93%.
      
      http://www.corp.google.com/~yaowu/no_crawl/mulcontext.html
      
      Change-Id: I15bc9697f6ff7829042911fe0c62930585d7e65d
      acf5d20c
  27. 22 Nov, 2011 1 commit
    • Paul Wilkins's avatar
      Removal of Qindex LUTS. · d39b5d05
      Paul Wilkins authored
      One of the problems arising when tweaking or adjusting the quantizer
      tables is that there are a lot of look up tables that depend on the QINDEX.
      Any adjustment to the link between QINDEX and real quantizer therefore tends
      to break aspects of for example the rate control.
      
      In this check in I have replaced several of the look up tables with functions that
      approximate the same results as the old Q luts but use a formulaic approach
      based on real Q values rather than QIndex. This should hopefully make it easier
      to experiment with changes to the Q tables without always having to go through
      and hand optimize a set of look up tables. Once things stabilize we may choose
      to re-instate luts for the sake of performance.
      
      Patch 2:
          Addressed Ronald's comments.
          vp8_init_me_luts() Added so luts only initialized once.
      
      Change-Id: Ic80db2212d2fd01e08e8cb5c7dca1fda1102be57
      d39b5d05
  28. 17 Nov, 2011 1 commit
    • Adrian Grange's avatar
      Clip buffer level to the maximum buffer size in CBR · eb15fe85
      Adrian Grange authored
      The buffer level was able to increase indefinitely rather than
      being clipped to the maximum buffer size specified by the user.
      
      This change checks the buffrer level and prevents it from
      going beyond the upper limit of the buffer.
      
      Change-Id: Ifff55f79d3c018e4d3d77e554b11ada543cc1654
      eb15fe85
  29. 16 Sep, 2011 2 commits
    • Yaowu Xu's avatar
      add quantizer adaptive intra mb mode encoding · aac2c126
      Yaowu Xu authored
      make intra mode coding entropy distribution adaptive to baseQindex, an
      encoding test on hd clips with all key frame shows universal gain on
      all clips in both .2%(psnr) and (ssim).3%.
      
      To build and test, configure with
      --enable-experimental --enable-qimode
      
      Change-Id: Iaa69241b984d4fdd8baa6d77ee78c0140f5ac00a
      aac2c126
    • Yaowu Xu's avatar
      add 8x8 intra prediction modes · ca6b85aa
      Yaowu Xu authored
      Patch 1 to Patch 3 is an initial implementation of 8x8 intra prediction
      modes, here are with the following assumptions:
      a. 8x8 has 4 prediction modes DC, H, V and TM
      b. UV 4x4 block use the same mode as corresponding 8x8 area
      c. i8x8 modes are enabled for key frame only for now
      Patch 4:
      d. removed debug code from previous patches
      Patch 5:
      e. added stats code to collect entropy stats and further cleaned up
      Patch 6:
      f. changed mode stats code to collect finer stats of modes
      Patch 7:
      g. normalized i8x8 modes distribution to total at 256 (8bits).
      Patch 8:
      h. fixed a bug in decoder and removed debug printf output.
      Patch 9:
      i. more cleanups to address paul's comment
      Patch 10:
      j. messy rebase/merges to bring the commit up to date.
      
      Tests on HD clips encoded with all key frame showing consistent gain
      on all clips and all metrics:~0.5%(psnr) and 0.6%(ssim):
      http://www.corp.google.com/~yaowu/no_crawl/i8x8hd_allkey_fixedq.html
      
      To build and test, configure with:
      --enable-experimental --enable-i8x8
      
      Change-Id: I9813fe07ae48cab5fdb5d904bca022514ad01e7f
      ca6b85aa
  30. 12 Aug, 2011 1 commit
    • John Koleszar's avatar
      Revert "Improved 1-pass CBR rate control" · e9613170
      John Koleszar authored
      This reverts commit b5ea2fbc. Further
      testing showed noticable keyframe popping in some cases, reverting this
      for now to give time for a proper fix.
      
      Conflicts:
      
      	vp8/encoder/onyx_if.c
      	vp8/encoder/ratectrl.c
      
      Change-Id: I159f53d1bf0e24c035754ab3ded8ccfd58fd04af
      e9613170
  31. 26 Jul, 2011 1 commit
  32. 18 Jul, 2011 1 commit
    • John Koleszar's avatar
      Improved 1-pass CBR rate control · b5ea2fbc
      John Koleszar authored
      This patch attempts to improve the handling of CBR streams with
      respect to the short term buffering requirements. The "buffer level"
      is changed to be an average over the rc buffer, rather than a long
      running average. Overshoot is also tracked over the same interval
      and the golden frame targets suppressed accordingly to correct for
      overly aggressive boosting.
      
      Testing shows that this is fairly consistently positive in one
      metric or another -- some clips that show significant decreases
      in quality have better buffering characteristics, others show
      improvenents in both.
      
      Change-Id: I924c89aa9bdb210271f2e03311e63de3f1f8f920
      b5ea2fbc
  33. 23 Jun, 2011 1 commit
    • John Koleszar's avatar
      Revert "Reduce overshoot in 1 pass rate control" · db67dcba
      John Koleszar authored
      This reverts commit 212f6183.
      
      Further testing shows that the overshoot accumulation/damping is too
      aggressive on some clips. Allowing the accumulated overshoot to
      decay and limiting to damping to golden frames shows some promise.
      But some clips show significant overshoot in the buffer window, so
      I think this still needs work.
      
      Change-Id: Ic02a9ca34f55229f9cc04786f4fab54cdc1a3ef5
      db67dcba
  34. 03 Jun, 2011 1 commit
    • John Koleszar's avatar
      Reduce overshoot in 1 pass rate control · 212f6183
      John Koleszar authored
      This patch attempts to reduce the peak bitrate hit by the encoder
      when using small buffer windows.
      
      Tested on the CIF set over 200-500kbps using these settings:
      
        --buf-sz=500 --buf-initial-sz=250 --buf-optimal-sz=250 \
        --undershoot-pct=100
      
      Two pass encodes were tested at best quality. One pass encodes were
      tested only at realtime speed 4:
      
        --rt --cpu-used=-4
      
      The peak datarate (over the specified 500ms window) was measured
      for each encode, and averaged together to get metric for
      "average peak," computed as SUM(peak)/SUM(target). This patch
      reduces the average peak datarate as follows:
      
        One pass:
          baseline:   1.29715
          this patch: 1.23664
      
        Two pass:
          baseline:   1.32702
          this patch: 1.37824
      
      This change had a positive effect on our quality metrics as well:
      
        One pass CBR:
                          Min  / Mean / Max (pct)
          Average PSNR    -0.42 / 2.86 / 27.32
          Overall PSNR    -0.90 / 2.00 / 17.27
          SSIM            -0.05 / 3.95 / 37.46
      
        Two pass CBR:
                          Min  / Mean / Max (pct)
          Average PSNR    -4.47 / 4.35 / 35.99
          Overall PSNR    -3.40 / 4.18 / 36.46
          SSIM            -4.56 / 6.98 / 53.67
      
        One pass VBR:
                          Min  / Mean / Max (pct)
          Average PSNR    -5.21 /  0.01 / 3.30
          Overall PSNR    -8.10 / -0.38 / 1.21
          SSIM            -7.38 / -0.11 / 3.17
          (note: most values here were close to the mean, there were a few
           outliers on files that were very sensitive to golden frame size)
      
        Two pass VBR:
                          Min  / Mean / Max (pct)
          Average PSNR    0.00 / 0.00 / 0.00
          Overall PSNR    0.00 / 0.00 / 0.00
          SSIM            0.00 / 0.00 / 0.00
      
      Neither one pass or two pass CBR mode adheres particularly strictly
      to the short term buffer constraints, and two pass is less
      consistent, even in the baseline commit. This should be addressed
      in a later commit. This likely will hurt the quality numbers, as it
      will have to reduce the burstiness of golden frames.
      
      Aside: My work on this commit makes it clear that we need to make
      rate control modes "pluggable", where you can easily write a new
      one or work on one in isolation.
      
      Change-Id: I1ea9a48f2beedd59891f1288aabf7064956b4716
      212f6183
  35. 19 May, 2011 1 commit
    • John Koleszar's avatar
      cleanup: collect twopass variables · 63cb1a7c
      John Koleszar authored
      This patch collects the twopass specific memebers of VP8_COMP into a
      dedicated struct. This is a first step towards isolating the two pass
      rate control and aids readability by decorating these variables with
      the 'twopass.' namespace. This makes it clear to the reader in what
      contexts the variable will be valid, and is a hint that a section of
      code might be a good candidate to move to firstpass.c in later
      refactoring. There likely will be other rate control modes that need
      their own specific data as well.
      
      This notation is probably overly verbose in firstpass.c, so an
      alternative would be to access this struct through a pointer like
      'rc->' instead of 'cpi->firstpass.' in that file. Feel free to make
      a review comment to that effect if you prefer.
      
      Change-Id: I0ab8254647cb4b493a77c16b5d236d0d4a94ca4d
      63cb1a7c