FFmpeg: libavcodec/opus/dsp.c Source File

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dsp.c

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1 /*

2 * This file is part of FFmpeg.

3 *

4 * FFmpeg is free software; you can redistribute it and/or

5 * modify it under the terms of the GNU Lesser General Public

6 * License as published by the Free Software Foundation; either

7 * version 2.1 of the License, or (at your option) any later version.

8 *

9 * FFmpeg is distributed in the hope that it will be useful,

10 * but WITHOUT ANY WARRANTY; without even the implied warranty of

11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

12 * Lesser General Public License for more details.

13 *

14 * You should have received a copy of the GNU Lesser General Public

15 * License along with FFmpeg; if not, write to the Free Software

16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

17 */

19 #include "config.h"

20 #include "libavutil/attributes.h"

21 #include "libavutil/mem_internal.h"

22 #include "dsp.h"

24 static void postfilter_c(float *data, int period, float *gains, int len)

25 {

26 const float g0 = gains[0];

27 const float g1 = gains[1];

28 const float g2 = gains[2];

30 float x4 = data[-period - 2];

31 float x3 = data[-period - 1];

32 float x2 = data[-period + 0];

33 float x1 = data[-period + 1];

35 for (int i = 0; i < len; i++) {

36 float x0 = data[i - period + 2];

37 data[i] += g0 * x2 +

38 g1 * (x1 + x3) +

39 g2 * (x0 + x4);

40 x4 = x3;

41 x3 = x2;

42 x2 = x1;

43 x1 = x0;

44 }

45 }

47 static float deemphasis_c(float *y, float *x, float coeff, const float *weights, int len)

48 {

49 const float c = weights[0];

50 for (int i = 0; i < len; i++)

51 coeff = y[i] = x[i] + coeff*c;

53 return coeff;

54 }

56 av_cold void ff_opus_dsp_init(OpusDSP *ctx)

57 {

58 ctx->postfilter = postfilter_c;

59 ctx->deemphasis = deemphasis_c;

61 #if ARCH_AARCH64

62 ff_opus_dsp_init_aarch64(ctx);

63 #elif ARCH_RISCV

64 ff_opus_dsp_init_riscv(ctx);

65 #elif ARCH_X86

66 ff_opus_dsp_init_x86(ctx);

67 #endif

68 }

ff_opus_dsp_init_aarch64

av_cold void ff_opus_dsp_init_aarch64(OpusDSP *ctx)

Definition: opusdsp_init.c:28

mem_internal.h

ff_opus_dsp_init_riscv

void ff_opus_dsp_init_riscv(OpusDSP *ctx)

Definition: opusdsp_init.c:30

data

const char data[16]

Definition: mxf.c:148

av_cold

#define av_cold

Definition: attributes.h:90

postfilter_c

static void postfilter_c(float *data, int period, float *gains, int len)

Definition: dsp.c:24

ctx

AVFormatContext * ctx

Definition: movenc.c:49

period

it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option keep it simple and lowercase description are in without period

Definition: writing_filters.txt:89

Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c

Definition: undefined.txt:32

ff_opus_dsp_init

av_cold void ff_opus_dsp_init(OpusDSP *ctx)

Definition: dsp.c:56

attributes.h

#define i(width, name, range_min, range_max)

Definition: cbs_h2645.c:256

weights

static const int weights[]

Definition: hevc_pel.c:32

dsp.h

len