/* * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com> * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef AVRESAMPLE_DITHER_H #define AVRESAMPLE_DITHER_H #include "avresample.h" #include "audio_data.h" typedef struct DitherContext DitherContext; typedef struct DitherDSPContext { /** * Convert samples from flt to s16 with added dither noise. * * @param dst destination float array, range -0.5 to 0.5 * @param src source int array, range INT_MIN to INT_MAX. * @param dither float dither noise array * @param len number of samples */ void (*quantize)(int16_t *dst, const float *src, float *dither, int len); int ptr_align; ///< src and dst constraits for quantize() int samples_align; ///< len constraits for quantize() /** * Convert dither noise from int to float with triangular distribution. * * @param dst destination float array, range -0.5 to 0.5 * constraints: 32-byte aligned * @param src0 source int array, range INT_MIN to INT_MAX. * the array size is len * 2 * constraints: 32-byte aligned * @param len number of output noise samples * constraints: multiple of 16 */ void (*dither_int_to_float)(float *dst, int *src0, int len); } DitherDSPContext; /** * Allocate and initialize a DitherContext. * * The parameters in the AVAudioResampleContext are used to initialize the * DitherContext. * * @param avr AVAudioResampleContext * @return newly-allocated DitherContext */ DitherContext *ff_dither_alloc(AVAudioResampleContext *avr, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt, int channels, int sample_rate, int apply_map); /** * Free a DitherContext. * * @param c DitherContext */ void ff_dither_free(DitherContext **c); /** * Convert audio sample format with dithering. * * @param c DitherContext * @param dst destination audio data * @param src source audio data * @return 0 if ok, negative AVERROR code on failure */ int ff_convert_dither(DitherContext *c, AudioData *dst, AudioData *src); /* arch-specific initialization functions */ void ff_dither_init_x86(DitherDSPContext *ddsp, enum AVResampleDitherMethod method); #endif /* AVRESAMPLE_DITHER_H */