From c8af852b97447491823ff9b91413e32415e2babf Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Fri, 23 Mar 2012 17:42:17 -0400 Subject: Add libavresample This is a new library for audio sample format, channel layout, and sample rate conversion. --- libavresample/avresample.h | 283 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 283 insertions(+) create mode 100644 libavresample/avresample.h (limited to 'libavresample/avresample.h') diff --git a/libavresample/avresample.h b/libavresample/avresample.h new file mode 100644 index 0000000..41688ed --- /dev/null +++ b/libavresample/avresample.h @@ -0,0 +1,283 @@ +/* + * Copyright (c) 2012 Justin Ruggles + * + * 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_AVRESAMPLE_H +#define AVRESAMPLE_AVRESAMPLE_H + +/** + * @file + * external API header + */ + +#include "libavutil/audioconvert.h" +#include "libavutil/avutil.h" +#include "libavutil/dict.h" +#include "libavutil/log.h" + +#include "libavresample/version.h" + +#define AVRESAMPLE_MAX_CHANNELS 32 + +typedef struct AVAudioResampleContext AVAudioResampleContext; + +/** Mixing Coefficient Types */ +enum AVMixCoeffType { + AV_MIX_COEFF_TYPE_Q6, /** 16-bit 10.6 fixed-point */ + AV_MIX_COEFF_TYPE_Q15, /** 32-bit 17.15 fixed-point */ + AV_MIX_COEFF_TYPE_FLT, /** floating-point */ + AV_MIX_COEFF_TYPE_NB, /** Number of coeff types. Not part of ABI */ +}; + +/** + * Return the LIBAVRESAMPLE_VERSION_INT constant. + */ +unsigned avresample_version(void); + +/** + * Return the libavresample build-time configuration. + * @return configure string + */ +const char *avresample_configuration(void); + +/** + * Return the libavresample license. + */ +const char *avresample_license(void); + +/** + * Get the AVClass for AVAudioResampleContext. + * + * Can be used in combination with AV_OPT_SEARCH_FAKE_OBJ for examining options + * without allocating a context. + * + * @see av_opt_find(). + * + * @return AVClass for AVAudioResampleContext + */ +const AVClass *avresample_get_class(void); + +/** + * Allocate AVAudioResampleContext and set options. + * + * @return allocated audio resample context, or NULL on failure + */ +AVAudioResampleContext *avresample_alloc_context(void); + +/** + * Initialize AVAudioResampleContext. + * + * @param avr audio resample context + * @return 0 on success, negative AVERROR code on failure + */ +int avresample_open(AVAudioResampleContext *avr); + +/** + * Close AVAudioResampleContext. + * + * This closes the context, but it does not change the parameters. The context + * can be reopened with avresample_open(). It does, however, clear the output + * FIFO and any remaining leftover samples in the resampling delay buffer. If + * there was a custom matrix being used, that is also cleared. + * + * @see avresample_convert() + * @see avresample_set_matrix() + * + * @param avr audio resample context + */ +void avresample_close(AVAudioResampleContext *avr); + +/** + * Free AVAudioResampleContext and associated AVOption values. + * + * This also calls avresample_close() before freeing. + * + * @param avr audio resample context + */ +void avresample_free(AVAudioResampleContext **avr); + +/** + * Generate a channel mixing matrix. + * + * This function is the one used internally by libavresample for building the + * default mixing matrix. It is made public just as a utility function for + * building custom matrices. + * + * @param in_layout input channel layout + * @param out_layout output channel layout + * @param center_mix_level mix level for the center channel + * @param surround_mix_level mix level for the surround channel(s) + * @param lfe_mix_level mix level for the low-frequency effects channel + * @param normalize if 1, coefficients will be normalized to prevent + * overflow. if 0, coefficients will not be + * normalized. + * @param[out] matrix mixing coefficients; matrix[i + stride * o] is + * the weight of input channel i in output channel o. + * @param stride distance between adjacent input channels in the + * matrix array + * @return 0 on success, negative AVERROR code on failure + */ +int avresample_build_matrix(uint64_t in_layout, uint64_t out_layout, + double center_mix_level, double surround_mix_level, + double lfe_mix_level, int normalize, double *matrix, + int stride); + +/** + * Get the current channel mixing matrix. + * + * @param avr audio resample context + * @param matrix mixing coefficients; matrix[i + stride * o] is the weight of + * input channel i in output channel o. + * @param stride distance between adjacent input channels in the matrix array + * @return 0 on success, negative AVERROR code on failure + */ +int avresample_get_matrix(AVAudioResampleContext *avr, double *matrix, + int stride); + +/** + * Set channel mixing matrix. + * + * Allows for setting a custom mixing matrix, overriding the default matrix + * generated internally during avresample_open(). This function can be called + * anytime on an allocated context, either before or after calling + * avresample_open(). avresample_convert() always uses the current matrix. + * Calling avresample_close() on the context will clear the current matrix. + * + * @see avresample_close() + * + * @param avr audio resample context + * @param matrix mixing coefficients; matrix[i + stride * o] is the weight of + * input channel i in output channel o. + * @param stride distance between adjacent input channels in the matrix array + * @return 0 on success, negative AVERROR code on failure + */ +int avresample_set_matrix(AVAudioResampleContext *avr, const double *matrix, + int stride); + +/** + * Set compensation for resampling. + * + * This can be called anytime after avresample_open(). If resampling was not + * being done previously, the AVAudioResampleContext is closed and reopened + * with resampling enabled. In this case, any samples remaining in the output + * FIFO and the current channel mixing matrix will be restored after reopening + * the context. + * + * @param avr audio resample context + * @param sample_delta compensation delta, in samples + * @param compensation_distance compensation distance, in samples + * @return 0 on success, negative AVERROR code on failure + */ +int avresample_set_compensation(AVAudioResampleContext *avr, int sample_delta, + int compensation_distance); + +/** + * Convert input samples and write them to the output FIFO. + * + * The output data can be NULL or have fewer allocated samples than required. + * In this case, any remaining samples not written to the output will be added + * to an internal FIFO buffer, to be returned at the next call to this function + * or to avresample_read(). + * + * If converting sample rate, there may be data remaining in the internal + * resampling delay buffer. avresample_get_delay() tells the number of remaining + * samples. To get this data as output, call avresample_convert() with NULL + * input. + * + * At the end of the conversion process, there may be data remaining in the + * internal FIFO buffer. avresample_available() tells the number of remaining + * samples. To get this data as output, either call avresample_convert() with + * NULL input or call avresample_read(). + * + * @see avresample_available() + * @see avresample_read() + * @see avresample_get_delay() + * + * @param avr audio resample context + * @param output output data pointers + * @param out_plane_size output plane size, in bytes. + * This can be 0 if unknown, but that will lead to + * optimized functions not being used directly on the + * output, which could slow down some conversions. + * @param out_samples maximum number of samples that the output buffer can hold + * @param input input data pointers + * @param in_plane_size input plane size, in bytes + * This can be 0 if unknown, but that will lead to + * optimized functions not being used directly on the + * input, which could slow down some conversions. + * @param in_samples number of input samples to convert + * @return number of samples written to the output buffer, + * not including converted samples added to the internal + * output FIFO + */ +int avresample_convert(AVAudioResampleContext *avr, void **output, + int out_plane_size, int out_samples, void **input, + int in_plane_size, int in_samples); + +/** + * Return the number of samples currently in the resampling delay buffer. + * + * When resampling, there may be a delay between the input and output. Any + * unconverted samples in each call are stored internally in a delay buffer. + * This function allows the user to determine the current number of samples in + * the delay buffer, which can be useful for synchronization. + * + * @see avresample_convert() + * + * @param avr audio resample context + * @return number of samples currently in the resampling delay buffer + */ +int avresample_get_delay(AVAudioResampleContext *avr); + +/** + * Return the number of available samples in the output FIFO. + * + * During conversion, if the user does not specify an output buffer or + * specifies an output buffer that is smaller than what is needed, remaining + * samples that are not written to the output are stored to an internal FIFO + * buffer. The samples in the FIFO can be read with avresample_read() or + * avresample_convert(). + * + * @see avresample_read() + * @see avresample_convert() + * + * @param avr audio resample context + * @return number of samples available for reading + */ +int avresample_available(AVAudioResampleContext *avr); + +/** + * Read samples from the output FIFO. + * + * During conversion, if the user does not specify an output buffer or + * specifies an output buffer that is smaller than what is needed, remaining + * samples that are not written to the output are stored to an internal FIFO + * buffer. This function can be used to read samples from that internal FIFO. + * + * @see avresample_available() + * @see avresample_convert() + * + * @param avr audio resample context + * @param output output data pointers + * @param nb_samples number of samples to read from the FIFO + * @return the number of samples written to output + */ +int avresample_read(AVAudioResampleContext *avr, void **output, int nb_samples); + +#endif /* AVRESAMPLE_AVRESAMPLE_H */ -- cgit v1.1