| 1 | /* |
| 2 | * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> |
| 3 | * |
| 4 | * This file is part of FFmpeg. |
| 5 | * |
| 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. |
| 10 | * |
| 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. |
| 15 | * |
| 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 |
| 19 | */ |
| 20 | |
| 21 | #ifndef AVRESAMPLE_DITHER_H |
| 22 | #define AVRESAMPLE_DITHER_H |
| 23 | |
| 24 | #include "avresample.h" |
| 25 | #include "audio_data.h" |
| 26 | |
| 27 | typedef struct DitherContext DitherContext; |
| 28 | |
| 29 | typedef struct DitherDSPContext { |
| 30 | /** |
| 31 | * Convert samples from flt to s16 with added dither noise. |
| 32 | * |
| 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 |
| 37 | */ |
| 38 | void (*quantize)(int16_t *dst, const float *src, float *dither, int len); |
| 39 | |
| 40 | int ptr_align; ///< src and dst constraits for quantize() |
| 41 | int samples_align; ///< len constraits for quantize() |
| 42 | |
| 43 | /** |
| 44 | * Convert dither noise from int to float with triangular distribution. |
| 45 | * |
| 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 |
| 53 | */ |
| 54 | void (*dither_int_to_float)(float *dst, int *src0, int len); |
| 55 | } DitherDSPContext; |
| 56 | |
| 57 | /** |
| 58 | * Allocate and initialize a DitherContext. |
| 59 | * |
| 60 | * The parameters in the AVAudioResampleContext are used to initialize the |
| 61 | * DitherContext. |
| 62 | * |
| 63 | * @param avr AVAudioResampleContext |
| 64 | * @return newly-allocated DitherContext |
| 65 | */ |
| 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); |
| 70 | |
| 71 | /** |
| 72 | * Free a DitherContext. |
| 73 | * |
| 74 | * @param c DitherContext |
| 75 | */ |
| 76 | void ff_dither_free(DitherContext **c); |
| 77 | |
| 78 | /** |
| 79 | * Convert audio sample format with dithering. |
| 80 | * |
| 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 |
| 85 | */ |
| 86 | int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src); |
| 87 | |
| 88 | /* arch-specific initialization functions */ |
| 89 | |
| 90 | void ff_dither_init_x86(DitherDSPContext *ddsp, |
| 91 | enum AVResampleDitherMethod method); |
| 92 | |
| 93 | #endif /* AVRESAMPLE_DITHER_H */ |