mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-26 17:32:06 +00:00
7539a1fee2
AC3DSPContext.ac3_max_msb_abs_int16() finds the maximum MSB of the absolute
value of each element in an array of int16_t.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
(cherry picked from commit fbb6b49dab)
61 lines
1.7 KiB
C
61 lines
1.7 KiB
C
/*
|
|
* AC-3 DSP utils
|
|
* Copyright (c) 2011 Justin Ruggles
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
#include "ac3dsp.h"
|
|
|
|
static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs)
|
|
{
|
|
int blk, i;
|
|
|
|
if (!num_reuse_blocks)
|
|
return;
|
|
|
|
for (i = 0; i < nb_coefs; i++) {
|
|
uint8_t min_exp = *exp;
|
|
uint8_t *exp1 = exp + 256;
|
|
for (blk = 0; blk < num_reuse_blocks; blk++) {
|
|
uint8_t next_exp = *exp1;
|
|
if (next_exp < min_exp)
|
|
min_exp = next_exp;
|
|
exp1 += 256;
|
|
}
|
|
*exp++ = min_exp;
|
|
}
|
|
}
|
|
|
|
static int ac3_max_msb_abs_int16_c(const int16_t *src, int len)
|
|
{
|
|
int i, v = 0;
|
|
for (i = 0; i < len; i++)
|
|
v |= abs(src[i]);
|
|
return v;
|
|
}
|
|
|
|
av_cold void ff_ac3dsp_init(AC3DSPContext *c)
|
|
{
|
|
c->ac3_exponent_min = ac3_exponent_min_c;
|
|
c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c;
|
|
|
|
if (HAVE_MMX)
|
|
ff_ac3dsp_init_x86(c);
|
|
}
|