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5 Commits

Author SHA1 Message Date
Lynne 134dba9544
opusdsp: add ability to modify deemphasis constant 
xHE-AAC relies on the same postfilter mechanism
that Opus uses to improve clarity (albeit with a steeper
deemphasis filter).

The code to apply it is identical, it's still just a
simple IIR low-pass filter. This commit makes it possible
to use alternative constants.
 2024-04-27 11:12:07 +02:00
Martin Storsjö a76b409dd0 aarch64: Reindent all assembly to 8/24 column indentation 
libavcodec/aarch64/vc1dsp_neon.S is skipped here, as it intentionally
uses a layered indentation style to visually show how different
unrolled/interleaved phases fit together.

Signed-off-by: Martin Storsjö <martin@martin.st>
 2023-10-21 23:25:54 +03:00
Martin Storsjö 7f905f3672 aarch64: Make the indentation more consistent 
Some functions have slightly different indentation styles; try
to match the surrounding code.

libavcodec/aarch64/vc1dsp_neon.S is skipped here, as it intentionally
uses a layered indentation style to visually show how different
unrolled/interleaved phases fit together.

Signed-off-by: Martin Storsjö <martin@martin.st>
 2023-10-21 23:25:29 +03:00
Lynne aac382e9e5 aarch64/opusdsp: do not clobber register v8 
A part of v8-v15 needs to be preserved across calls.
 2019-08-15 13:29:22 +01:00
Lynne 4d2f62150d aarch64/opusdsp: implement NEON accelerated postfilter and deemphasis 
153372 UNITS in postfilter_c,   65536 runs,      0 skips
73164 UNITS in postfilter_neon,   65536 runs,      0 skips -> 2.1x speedup

80591 UNITS in deemphasis_c,  131072 runs,      0 skips
43969 UNITS in deemphasis_neon,  131072 runs,      0 skips -> 1.83x speedup

Total decoder speedup: ~15% on a Raspberry Pi 3 (from 28.1x to 33.5x realtime)

Deemphasis SIMD based on the following unrolling:
const float c1 = CELT_EMPH_COEFF, c2 = c1*c1, c3 = c2*c1, c4 = c3*c1;
float state = coeff;

for (int i = 0; i < len; i += 4) {
    y[0] = x[0] + c1*state;
    y[1] = x[1] + c2*state + c1*x[0];
    y[2] = x[2] + c3*state + c1*x[1] + c2*x[0];
    y[3] = x[3] + c4*state + c1*x[2] + c2*x[1] + c3*x[0];

    state = y[3];
    y += 4;
    x += 4;
}

Unlike the x86 version, duplication is used instead of pslldq so
the structure and tables are different.
 2019-04-10 01:08:54 +02:00