FFmpeg: libswresample/soxr_resample.c Source File

soxr_resample.c

1 /*

2  * audio resampling with soxr

3  * Copyright (c) 2012 Rob Sykes <robs@users.sourceforge.net>

4  *

5  * This file is part of FFmpeg.

6  *

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

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

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

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

11  *

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

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

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

15  * Lesser General Public License for more details.

16  *

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

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

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

20  */

21 

22 /**

23  * @file

24  * audio resampling with soxr

25  */

26 

27 #include "libavutil/log.h"

28 #include "swresample_internal.h"

29 

30 #include <soxr.h>

31 

32  static struct ResampleContext *create(struct ResampleContext *c, int out_rate, int in_rate, int filter_size, int phase_shift, int linear,

33  double cutoff, enum AVSampleFormat format, enum SwrFilterType filter_type, int kaiser_beta, double precision, int cheby){

34  soxr_error_t error;

35 

36  soxr_datatype_t type =

37  format == AV_SAMPLE_FMT_S16P? SOXR_INT16_S :

38  format == AV_SAMPLE_FMT_S16 ? SOXR_INT16_I :

39  format == AV_SAMPLE_FMT_S32P? SOXR_INT32_S :

40  format == AV_SAMPLE_FMT_S32 ? SOXR_INT32_I :

41  format == AV_SAMPLE_FMT_FLTP? SOXR_FLOAT32_S :

42  format == AV_SAMPLE_FMT_FLT ? SOXR_FLOAT32_I :

43  format == AV_SAMPLE_FMT_DBLP? SOXR_FLOAT64_S :

44  format == AV_SAMPLE_FMT_DBL ? SOXR_FLOAT64_I : (soxr_datatype_t)-1;

45 

46  soxr_io_spec_t io_spec = soxr_io_spec(type, type);

47 

48  soxr_quality_spec_t q_spec = soxr_quality_spec((int)((precision-2)/4), (SOXR_HI_PREC_CLOCK|SOXR_ROLLOFF_NONE)*!!cheby);

49  q_spec.precision = linear? 0 : precision;

50 #if !defined SOXR_VERSION /* Deprecated @ March 2013: */

51  q_spec.bw_pc = cutoff? FFMAX(FFMIN(cutoff,.995),.8)*100 : q_spec.bw_pc;

52 #else

53  q_spec.passband_end = cutoff? FFMAX(FFMIN(cutoff,.995),.8) : q_spec.passband_end;

54 #endif

55 

56  soxr_delete((soxr_t)c);

57  c = (struct ResampleContext *)

58  soxr_create(in_rate, out_rate, 0, &error, &io_spec, &q_spec, 0);

59  if (!c)

60  av_log(NULL, AV_LOG_ERROR, "soxr_create: %s\n", error);

61  return c;

62 }

63 

64  static void destroy(struct ResampleContext * *c){

65  soxr_delete((soxr_t)*c);

66  *c = NULL;

67 }

68 

69  static int flush(struct SwrContext *s){

70  soxr_process((soxr_t)s->resample, NULL, 0, NULL, NULL, 0, NULL);

71  return 0;

72 }

73 

74  static int process(

75  struct ResampleContext * c, AudioData *dst, int dst_size,

76  AudioData *src, int src_size, int *consumed){

77  size_t idone, odone;

78  soxr_error_t error = soxr_set_error((soxr_t)c, soxr_set_num_channels((soxr_t)c, src->ch_count));

79  error = soxr_process((soxr_t)c, src->ch, (size_t)src_size,

80  &idone, dst->ch, (size_t)dst_size, &odone);

81  *consumed = (int)idone;

82  return error? -1 : odone;

83 }

84 

85  static int64_t get_delay(struct SwrContext *s, int64_t base){

86  double delay_s = soxr_delay((soxr_t)s->resample) / s->out_sample_rate;

87  return (int64_t)(delay_s * base + .5);

88 }

89 

90  struct Resampler const soxr_resampler={

91  create, destroy, process, flush, NULL /* set_compensation */, get_delay,

92 };

93