2 * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #ifndef AVRESAMPLE_DITHER_H
22 #define AVRESAMPLE_DITHER_H
24 #include "avresample.h"
25 #include "audio_data.h"
27 typedef struct DitherContext DitherContext;
29 typedef struct DitherDSPContext {
31 * Convert samples from flt to s16 with added dither noise.
33 * @param dst destination float array, range -0.5 to 0.5
34 * @param src source int array, range INT_MIN to INT_MAX.
35 * @param dither float dither noise array
36 * @param len number of samples
38 void (*quantize)(int16_t *dst, const float *src, float *dither, int len);
40 int ptr_align; ///< src and dst constraints for quantize()
41 int samples_align; ///< len constraints for quantize()
44 * Convert dither noise from int to float with triangular distribution.
46 * @param dst destination float array, range -0.5 to 0.5
47 * constraints: 32-byte aligned
48 * @param src0 source int array, range INT_MIN to INT_MAX.
49 * the array size is len * 2
50 * constraints: 32-byte aligned
51 * @param len number of output noise samples
52 * constraints: multiple of 16
54 void (*dither_int_to_float)(float *dst, int *src0, int len);
58 * Allocate and initialize a DitherContext.
60 * The parameters in the AVAudioResampleContext are used to initialize the
63 * @param avr AVAudioResampleContext
64 * @return newly-allocated DitherContext
66 DitherContext *ff_dither_alloc(AVAudioResampleContext *avr,
67 enum AVSampleFormat out_fmt,
68 enum AVSampleFormat in_fmt,
69 int channels, int sample_rate, int apply_map);
72 * Free a DitherContext.
74 * @param c DitherContext
76 void ff_dither_free(DitherContext **c);
79 * Convert audio sample format with dithering.
81 * @param c DitherContext
82 * @param dst destination audio data
83 * @param src source audio data
84 * @return 0 if ok, negative AVERROR code on failure
86 int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src);
88 /* arch-specific initialization functions */
90 void ff_dither_init_x86(DitherDSPContext *ddsp,
91 enum AVResampleDitherMethod method);
93 #endif /* AVRESAMPLE_DITHER_H */