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avcodec/aacpsy: Fix AAC Psy PE reduction calculation when multiple iterations are required

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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: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Claudio Freire 2015-03-01 20:11:12 -03:00 committed by Michael Niedermayer
parent bfdd15c4e8
commit 84f4be424d
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
libavcodec/aacpsy.c
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@ -717,7 +717,7 @@ static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel,
}
desired_pe_no_ah = FFMAX(desired_pe - (pe - pe_no_ah), 0.0f);
if (active_lines > 0.0f)
reduction += calc_reduction_3gpp(a, desired_pe_no_ah, pe_no_ah, active_lines);
reduction = calc_reduction_3gpp(a, desired_pe_no_ah, pe_no_ah, active_lines);
pe = 0.0f;
for (w = 0; w < wi->num_windows*16; w += 16) {

2
tests/fate/aac.mak
View File

@ -91,7 +91,7 @@ fate-aac-aref-encode: CMD = enc_dec_pcm adts wav s16le $(REF) -strict -2 -c:a aa
fate-aac-aref-encode: CMP = stddev
fate-aac-aref-encode: REF = ./tests/data/asynth-44100-2.wav
fate-aac-aref-encode: CMP_SHIFT = -4096
fate-aac-aref-encode: CMP_TARGET = 1862
fate-aac-aref-encode: CMP_TARGET = 438
fate-aac-aref-encode: SIZE_TOLERANCE = 2464
FATE_AAC_ENCODE += fate-aac-ln-encode