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6 Commits

Author SHA1 Message Date
Ben Avison
42c1cc35b7 armv6: Accelerate ff_imdct_half for general case (mdct_bits != 6)
The previous implementation targeted DTS Coherent Acoustics, which only
requires mdct_bits == 6. This relatively small size lent itself to
unrolling the loops a small number of times, and encoding offsets
calculated at assembly time within the load/store instructions of each
iteration.

In the more general case (codecs such as AAC and AC3) much larger arrays
are used - mdct_bits == [8, 9, 11]. The old method does not scale for
these cases, so more integer registers are used with non-unrolled versions
of the loops (and with some stack spillage). The postrotation filter loop
is still unrolled by a factor of 2 to permit the double-buffering of some
VFP registers to facilitate overlap of neighbouring iterations.

I benchmarked the result by measuring the number of gperftools samples
that hit anywhere in the AAC decoder (starting from aac_decode_frame())
or specifically in ff_imdct_half_c / ff_imdct_half_vfp, for the same
example AAC stream:

                  Before          After
                  Mean   StdDev   Mean   StdDev  Confidence  Change
aac_decode_frame  2368.1 35.8     2117.2 35.3    100.0%      +11.8%
ff_imdct_half_*   457.5  22.4     251.2  16.2    100.0%      +82.1%

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2014-07-13 15:17:04 +02:00
Martin Storsjö
47d57f24e3 arm: Mangle external symbols properly in new vfp assembly files
Reviewed-by: Kostya Shishkov
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2013-07-22 13:16:21 +02:00
Michael Niedermayer
c30eb74d18 Merge commit '8b9eba664edaddf9a304d3acbf0388b5c520781d'
* commit '8b9eba664edaddf9a304d3acbf0388b5c520781d':
  arm: Add VFP-accelerated version of fft16

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2013-07-22 12:05:39 +02:00
Michael Niedermayer
2305a6775d Merge commit 'b63bb251ea6d6ba23295294e37a92625c0192206'
* commit 'b63bb251ea6d6ba23295294e37a92625c0192206':
  arm: Add VFP-accelerated version of imdct_half

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2013-07-22 11:57:05 +02:00
Martin Storsjö
8b9eba664e arm: Add VFP-accelerated version of fft16
Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   1389.3  4.2       967.8  35.1   +43.6%
Overall        15577.5 83.2     15400.0 336.4    +1.2%

Signed-off-by: Martin Storsjö <martin@martin.st>
2013-07-22 10:15:41 +03:00
Martin Storsjö
b63bb251ea arm: Add VFP-accelerated version of imdct_half
Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   2653.0  28.5     1108.8  51.4   +139.3%
Overall        17049.5 408.2    15973.0 223.2     +6.7%

Signed-off-by: Martin Storsjö <martin@martin.st>
2013-07-22 10:15:37 +03:00