1. 26 Mar, 2017 1 commit
  2. 13 Nov, 2016 1 commit
  3. 31 May, 2016 1 commit
  4. 06 Apr, 2016 1 commit
    • Claudio Freire's avatar
      AAC encoder: fix valgrind errors · 8005b6de
      Claudio Freire authored
      Move wi.clipping computation outside of psy_lame_window, LFE
      channels don't even call that, and make the LFE path also
      initialize window_type[1] which is needed by analyze_channel
      8005b6de
  5. 05 Apr, 2016 1 commit
  6. 23 Mar, 2016 1 commit
  7. 22 Mar, 2016 1 commit
  8. 25 Dec, 2015 1 commit
  9. 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
  10. 29 Nov, 2015 1 commit
    • Claudio Freire's avatar
      AAC encoder: make pe.min a local minimum · 88e498a8
      Claudio Freire authored
      As noted in a comment, pe.min in the reference encoder
      is centered around current pe. The bit reservoir algo
      needs pe.min to be a local minimum, because it can only
      account for local PE variations. If it's set to a global
      minimum as was being done, bit reservoir logic doesn't
      work as efficiently.
      
      This patch tries to forget old minimums and converge to
      a local minimum without losing the stability of the
      previous solution. Listening tests until now suggest this
      solves numerous RC issues.
      88e498a8
  11. 11 Oct, 2015 2 commits
    • Claudio Freire's avatar
      AAC encoder: cosmetics from last commit · 323d3752
      Claudio Freire authored
      Reindent
      323d3752
    • 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
  12. 23 Sep, 2015 1 commit
    • Claudio Freire's avatar
      AAC encoder: tweak rate-distortion logic · 7ec74ae4
      Claudio Freire authored
      This patch modifies the encode frame function to
      retry encoding the frame when the resulting bit count
      is too far off target, but only adjusting lambda
      in small, incremental step. It also makes the logic
      more conservative - otherwise it will contend with
      bit reservoir-related variations in bit allocation,
      and result in artifacts when frame have to be truncated
      (usually at high bit rates transitioning from low
      complexity to high complexity).
      7ec74ae4
  13. 27 Jul, 2015 2 commits
    • Vittorio Giovara's avatar
      lavc: AV-prefix all codec flags · 7c6eb0a1
      Vittorio Giovara authored
      Convert doxygen to multiline and express bitfields more simply.
      Signed-off-by: 's avatarVittorio Giovara <vittorio.giovara@gmail.com>
      7c6eb0a1
    • Claudio Freire's avatar
      AAC Encoder: clipping avoidance · 59216e05
      Claudio Freire authored
      Avoid clipping due to quantization noise to produce audible
      artifacts, by detecting near-clipping signals and both attenuating
      them a little and encoding escape-encoded bands (usually the
      loudest) rounding towards zero instead of nearest, which tends to
      decrease overall energy and thus clipping.
      
      Currently fate tests measure numerical error so this change makes
      tests using asynth (which are near clipping) report higher error
      not less, because of window attenuation. Yet, they sound better,
      not worse (albeit subtle, other samples aren't subtle at all).
      Only measuring psychoacoustically weighted error would make for
      a representative test, so that will be left for a future patch.
      Signed-off-by: 's avatarMichael Niedermayer <michael@niedermayer.cc>
      59216e05
  14. 03 Jul, 2015 1 commit
  15. 28 Jun, 2015 1 commit
  16. 31 May, 2015 2 commits
  17. 05 May, 2015 1 commit
  18. 21 Apr, 2015 1 commit
  19. 16 Apr, 2015 1 commit
  20. 02 Mar, 2015 1 commit
    • Claudio Freire's avatar
      avcodec/aacpsy: Fix AAC Psy PE reduction calculation when multiple iterations are required · 84f4be42
      Claudio Freire authored
      This is a small change, but it does have a big impact on bit allocation.
      
      all the regressions marked in the report have no audible
      difference (I didn't check them all though), but the improvements can
      be heard.
      
      This affects mostly high bit rates. It's related to issue #2686.
      
      In the report, A is the patched version, B is unpatched, all
      comparisons show deltas in the form (A-B), so a positive pSNR delta
      means a better quality in the patched version, and negative a
      regression. Regressions are only considered for pSNR deltas below
      -1db, they're considered serious below -6db.
      
      All measurements were done with tiny_psnr.
      
      The summary of the report inline for quick reading:
      
      Files: 58
      Bitrates: 6
      Tests: 347
      Serious Regressions: 0 (0%)
      Regressions: 10 (2%)
      Improvements: 54 (15%)
      Big improvements: 26 (7%)
      Worst regression - sine_tester.flac - 384k
        - StdDev: 1.68        pSNR: -3.05     maxdiff: -178.00
      Best improvement - 07 - Bound.flac - 384k
        - StdDev: -1700.05    pSNR: 20.64     maxdiff: -29595.00
      Average          - StdDev: -55.67       pSNR: 1.20      maxdiff: -1593.00
      Signed-off-by: 's avatarMichael Niedermayer <michaelni@gmx.at>
      84f4be42
  21. 14 Feb, 2015 1 commit
  22. 08 Jun, 2014 1 commit
  23. 14 May, 2013 1 commit
  24. 04 May, 2013 2 commits
  25. 03 May, 2013 1 commit
  26. 23 Mar, 2013 1 commit
  27. 07 Mar, 2013 1 commit
  28. 20 Dec, 2012 1 commit
  29. 14 Sep, 2012 2 commits
  30. 09 Sep, 2012 1 commit
  31. 29 Jul, 2012 1 commit
  32. 26 May, 2012 1 commit
  33. 28 Mar, 2012 1 commit
  34. 23 Jan, 2012 2 commits