On Tue, Oct 27, 2015 at 9:38 PM, Ganesh Ajjanagadde
<gajjanaga...@gmail.com> wrote:
> When sbr->reset is set in encode_frame, a bunch of qsort calls might get made.
> Thus, there is the potential of calling qsort whenever the spectral
> contents change.
>
> AV_QSORT is substantially faster due to the inlining of the comparison
> callback.
> Thus, the increase in performance should be worth the increase in binary size.
>
> Tested with FATE.
>
> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com>
>
> --------------------------------------------------------------------------------
> Please note that I am not not knowledgable about AAC, and above analysis
> was based on a quick glance at the code. I could not get benchmarks with
> runs > 1 easily (even with stream_loop), hence they are omitted.
> Furthermore, it seems like AAC is under active work, so I defer
> meaningful benchmarks to the maintainers.
> ---
> libavcodec/aacsbr_template.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/libavcodec/aacsbr_template.c b/libavcodec/aacsbr_template.c
> index d31b71e..9561ba0 100644
> --- a/libavcodec/aacsbr_template.c
> +++ b/libavcodec/aacsbr_template.c
> @@ -32,6 +32,8 @@
> * @author Zoran Basaric ( zoran.basa...@imgtec.com )
> */
>
> +#include "libavutil/qsort.h"
> +
> av_cold void AAC_RENAME(ff_aac_sbr_init)(void)
> {
> static const struct {
> @@ -138,8 +140,8 @@ static void sbr_make_f_tablelim(SpectralBandReplication
> *sbr)
> memcpy(sbr->f_tablelim + sbr->n[0] + 1, patch_borders + 1,
> (sbr->num_patches - 1) * sizeof(patch_borders[0]));
>
> - qsort(sbr->f_tablelim, sbr->num_patches + sbr->n[0],
> - sizeof(sbr->f_tablelim[0]),
> + AV_QSORT(sbr->f_tablelim, sbr->num_patches + sbr->n[0],
> + uint16_t,
> qsort_comparison_function_int16);
>
> sbr->n_lim = sbr->n[0] + sbr->num_patches - 1;
> @@ -296,7 +298,7 @@ static int sbr_make_f_master(AACContext *ac,
> SpectralBandReplication *sbr,
> if (spectrum->bs_stop_freq < 14) {
> sbr->k[2] = stop_min;
> make_bands(stop_dk, stop_min, 64, 13);
> - qsort(stop_dk, 13, sizeof(stop_dk[0]),
> qsort_comparison_function_int16);
> + AV_QSORT(stop_dk, 13, int16_t, qsort_comparison_function_int16);
> for (k = 0; k < spectrum->bs_stop_freq; k++)
> sbr->k[2] += stop_dk[k];
> } else if (spectrum->bs_stop_freq == 14) {
> @@ -389,7 +391,7 @@ static int sbr_make_f_master(AACContext *ac,
> SpectralBandReplication *sbr,
>
> make_bands(vk0+1, sbr->k[0], sbr->k[1], num_bands_0);
>
> - qsort(vk0 + 1, num_bands_0, sizeof(vk0[1]),
> qsort_comparison_function_int16);
> + AV_QSORT(vk0 + 1, num_bands_0, int16_t,
> qsort_comparison_function_int16);
> vdk0_max = vk0[num_bands_0];
>
> vk0[0] = sbr->k[0];
> @@ -430,13 +432,13 @@ static int sbr_make_f_master(AACContext *ac,
> SpectralBandReplication *sbr,
>
> if (vdk1_min < vdk0_max) {
> int change;
> - qsort(vk1 + 1, num_bands_1, sizeof(vk1[1]),
> qsort_comparison_function_int16);
> + AV_QSORT(vk1 + 1, num_bands_1, int16_t,
> qsort_comparison_function_int16);
> change = FFMIN(vdk0_max - vk1[1], (vk1[num_bands_1] -
> vk1[1]) >> 1);
> vk1[1] += change;
> vk1[num_bands_1] -= change;
> }
>
> - qsort(vk1 + 1, num_bands_1, sizeof(vk1[1]),
> qsort_comparison_function_int16);
> + AV_QSORT(vk1 + 1, num_bands_1, int16_t,
> qsort_comparison_function_int16);
>
> vk1[0] = sbr->k[1];
> for (k = 1; k <= num_bands_1; k++) {
> --
> 2.6.2
>
Ping: Rostislav, Nedeljko, Claudio, any others interested.
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