1. 17 Dec, 2016 1 commit
  2. 13 Dec, 2016 2 commits
  3. 23 Oct, 2016 1 commit
  4. 13 Oct, 2016 1 commit
  5. 23 Sep, 2016 1 commit
  6. 30 May, 2016 1 commit
  7. 23 May, 2016 3 commits
  8. 21 May, 2016 4 commits
  9. 17 May, 2016 1 commit
  10. 29 Mar, 2016 1 commit
  11. 09 Mar, 2016 1 commit
  12. 04 Mar, 2016 1 commit
  13. 31 Jan, 2016 1 commit
  14. 29 Jan, 2016 1 commit
  15. 19 Jan, 2016 1 commit
  16. 13 Jan, 2016 1 commit
    • Claudio Freire's avatar
      AAC encoder: various fixes in M/S coding · 6711aa21
      Claudio Freire authored
      1. Fix sf_idx and band_type addressing to address only the first
      subwindow in the group (others could hold garbage values)
      
      2. Don't step on ms_mask when is_mask is set. I/S selection
      already sets the ms_mask properly and shouldn't be overridden.
      
      3. Use mid/sid cb/sf when computing coding error, as should be
      since those are the cb/sfs that will eventually be set.
      
      4. Fix distortion computation on multi-subwindow groups (was
      subtracting the bits terms multiple times)
      
      5. Clear ms_mask when one side uses PNS and the other doesn't.
      When using PNS, ms_mask signals correlated noise, which can be
      detected just like regular M/S detection, so we don't skip
      noise bands, but when only one side uses PNS setting the flag
      can confuse some encoders, so avoid that.
      6711aa21
  17. 04 Dec, 2015 1 commit
  18. 02 Dec, 2015 1 commit
    • Claudio Freire's avatar
      AAC encoder: improve SF range utilization · ca203e99
      Claudio Freire authored
      This patch does 4 things, all of which interact and thus it
      woudln't be possible to commit them separately without causing
      either quality regressions or assertion failures.
      
      Fate comparison targets don't all reflect improvements in
      quality, yet listening tests show substantially improved quality
      and stability.
      
      1. Increase SF range utilization.
      
      The spec requires SF delta values to be constrained within the
      range -60..60. The previous code was applying that range to
      the whole SF array and not only the deltas of consecutive values,
      because doing so requires smarter code: zeroing or otherwise
      skipping a band may invalidate lots of SF choices.
      
      This patch implements that logic to allow the coders to utilize
      the full dynamic range of scalefactors, increasing quality quite
      considerably, and fixing delta-SF-related assertion failures,
      since now the limitation is enforced rather than asserted.
      
      2. PNS tweaks
      
      The previous modification makes big improvements in twoloop's
      efficiency, and every time that happens PNS logic needs to be
      tweaked accordingly to avoid it from stepping all over twoloop's
      decisions. This patch includes modifications of the sort.
      
      3. Account for lowpass cutoff during PSY analysis
      
      The closer PSY's allocation is to final allocation the better
      the quality is, and given these modifications, twoloop is now
      very efficient at avoiding holes. Thus, to compute accurate
      thresholds, PSY needs to account for the lowpass applied
      implicitly during twoloop (by zeroing high bands).
      
      This patch makes twoloop set the cutoff in psymodel's context
      the first time it runs, and makes PSY account for it during
      threshold computation, making PE and threshold computations
      closer to the final allocation and thus achieving better
      subjective quality.
      
      4. Tweaks to RC lambda tracking loop in relation to PNS
      
      Without this tweak some corner cases cause quality regressions.
      Basically, lambda needs to react faster to overall bitrate
      efficiency changes since now PNS can be quite successful in
      enforcing maximum bitrates, when PSY allocates too many bits
      to the lower bands, suppressing the signals RC logic uses to
      lower lambda in those cases and causing aggressive PNS.
      
      This tweak makes PNS much less aggressive, though it can still
      use some further tweaks.
      
      Also update MIPS specializations and adjust fuzz
      
      Also in lavc/mips/aacpsy_mips.h: remove trailing whitespace
      ca203e99
  19. 13 Oct, 2015 1 commit
  20. 12 Oct, 2015 2 commits
  21. 11 Oct, 2015 1 commit
    • Claudio Freire's avatar
      AAC encoder: Extensive improvements · 01ecb717
      Claudio Freire authored
      This finalizes merging of the work in the patches in ticket #2686.
      
      Improvements to twoloop and RC logic are extensive.
      
      The non-exhaustive list of twoloop improvments includes:
       - Tweaks to distortion limits on the RD optimization phase of twoloop
       - Deeper search in twoloop
       - PNS information marking to let twoloop decide when to use it
         (turned out having the decision made separately wasn't working)
       - Tonal band detection and priorization
       - Better band energy conservation rules
       - Strict hole avoidance
      
      For rate control:
       - Use psymodel's bit allocation to allow proper use of the bit
         reservoir. Don't work against the bit reservoir by moving lambda
         in the opposite direction when psymodel decides to allocate more/less
         bits to a frame.
       - Retry the encode if the effective rate lies outside a reasonable
         margin of psymodel's allocation or the selected ABR.
       - Log average lambda at the end. Useful info for everyone, but especially
         for tuning of the various encoder constants that relate to lambda
         feedback.
      
      Psy:
       - Do not apply lowpass with a FIR filter, instead just let the coder
         zero bands above the cutoff. The FIR filter induces group delay,
         and while zeroing bands causes ripple, it's lost in the quantization
         noise.
       - Experimental VBR bit allocation code
       - Tweak automatic lowpass filter threshold to maximize audio bandwidth
         at all bitrates while still providing acceptable, stable quality.
      
      I/S:
       - Phase decision fixes. Unrelated to #2686, but the bugs only surfaced
         when the merge was finalized. Measure I/S band energy accounting for
         phase, and prevent I/S and M/S from being applied both.
      
      PNS:
       - Avoid marking short bands with PNS when they're part of a window
         group in which there's a large variation of energy from one window
         to the next. PNS can't preserve those and the effect is extremely
         noticeable.
      
      M/S:
       - Implement BMLD protection similar to the specified in
         ISO-IEC/13818:7-2003, Appendix C Section 6.1. Since M/S decision
         doesn't conform to section 6.1, a different method had to be
         implemented, but should provide equivalent protection.
       - Move the decision logic closer to the method specified in
         ISO-IEC/13818:7-2003, Appendix C Section 6.1. Specifically,
         make sure M/S needs less bits than dual stereo.
       - Don't apply M/S in bands that are using I/S
      
      Now, this of course needed adjustments in the compare targets and
      fuzz factors of the AAC encoder's fate tests, but if wondering why
      the targets go up (more distortion), consider the previous coder
      was using too many bits on LF content (far more than required by
      psy), and thus those signals will now be more distorted, not less.
      
      The extra distortion isn't audible though, I carried extensive
      ABX testing to make sure.
      
      A very similar patch was also extensively tested by Kamendo2 in
      the context of #2686.
      01ecb717
  22. 07 Oct, 2015 2 commits
  23. 02 Oct, 2015 1 commit
  24. 23 Sep, 2015 1 commit
  25. 18 Sep, 2015 1 commit
  26. 17 Sep, 2015 2 commits
    • Michael Niedermayer's avatar
    • Claudio Freire's avatar
      AAC encoder: refactor to resynchronize MIPS port · 8df9bf8e
      Claudio Freire authored
      This patch refactors the AAC coders to reuse code
      between the MIPS port and the regular, portable C code.
      There were two main functions that had to use
      hand-optimized versions of quantization code:
       - search_for_quantizers_twoloop
       - codebook_trellis_rate
      
      Those two were split into their own template header
      files so they can be inlined inside both the MIPS port
      and the generic code. In each context, they'll link
      to their specialized implementations, and thus be
      optimized by the compiler.
      
      This approach I believe is better than maintaining
      several copies of each function. As past experience has
      proven, having to keep those in sync was error prone.
      In this way, they will remain in sync by default.
      
      Also, an implementation of the dequantized output
      argument for the optimized quantize_and_encode
      functions is included in the patch. While the current
      implementation of search_for_pred still isn't using
      it, future iterations of main prediction probably will.
      It should not imply any measurable performance hit while
      not being used.
      8df9bf8e
  27. 14 Sep, 2015 2 commits
  28. 07 Sep, 2015 2 commits
  29. 03 Sep, 2015 1 commit