2 * Copyright (C) 2011-2012 Michael Niedermayer (michaelni@gmx.at)
4 * This file is part of libswresample
6 * libswresample 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 * libswresample 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 libswresample; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * libswresample public header
26 #ifndef SWRESAMPLE_SWRESAMPLE_H
27 #define SWRESAMPLE_SWRESAMPLE_H
30 #include "libavutil/samplefmt.h"
32 #include "libswresample/version.h"
34 #if LIBSWRESAMPLE_VERSION_MAJOR < 1
35 #define SWR_CH_MAX 32 ///< Maximum number of channels
38 #define SWR_FLAG_RESAMPLE 1 ///< Force resampling even if equal sample rate
39 //TODO use int resample ?
40 //long term TODO can we enable this dynamically?
44 SWR_DITHER_RECTANGULAR,
45 SWR_DITHER_TRIANGULAR,
46 SWR_DITHER_TRIANGULAR_HIGHPASS,
47 SWR_DITHER_NB, ///< not part of API/ABI
50 /** Resampling Filter Types */
52 SWR_FILTER_TYPE_CUBIC, /**< Cubic */
53 SWR_FILTER_TYPE_BLACKMAN_NUTTALL, /**< Blackman Nuttall Windowed Sinc */
54 SWR_FILTER_TYPE_KAISER, /**< Kaiser Windowed Sinc */
57 typedef struct SwrContext SwrContext;
60 * Get the AVClass for swrContext. It can be used in combination with
61 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
65 const AVClass *swr_get_class(void);
68 * Allocate SwrContext.
70 * If you use this function you will need to set the parameters (manually or
71 * with swr_alloc_set_opts()) before calling swr_init().
73 * @see swr_alloc_set_opts(), swr_init(), swr_free()
74 * @return NULL on error, allocated context otherwise
76 struct SwrContext *swr_alloc(void);
79 * Initialize context after user parameters have been set.
81 * @return AVERROR error code in case of failure.
83 int swr_init(struct SwrContext *s);
86 * Allocate SwrContext if needed and set/reset common parameters.
88 * This function does not require s to be allocated with swr_alloc(). On the
89 * other hand, swr_alloc() can use swr_alloc_set_opts() to set the parameters
90 * on the allocated context.
92 * @param s Swr context, can be NULL
93 * @param out_ch_layout output channel layout (AV_CH_LAYOUT_*)
94 * @param out_sample_fmt output sample format (AV_SAMPLE_FMT_*).
95 * @param out_sample_rate output sample rate (frequency in Hz)
96 * @param in_ch_layout input channel layout (AV_CH_LAYOUT_*)
97 * @param in_sample_fmt input sample format (AV_SAMPLE_FMT_*).
98 * @param in_sample_rate input sample rate (frequency in Hz)
99 * @param log_offset logging level offset
100 * @param log_ctx parent logging context, can be NULL
102 * @see swr_init(), swr_free()
103 * @return NULL on error, allocated context otherwise
105 struct SwrContext *swr_alloc_set_opts(struct SwrContext *s,
106 int64_t out_ch_layout, enum AVSampleFormat out_sample_fmt, int out_sample_rate,
107 int64_t in_ch_layout, enum AVSampleFormat in_sample_fmt, int in_sample_rate,
108 int log_offset, void *log_ctx);
111 * Free the given SwrContext and set the pointer to NULL.
113 void swr_free(struct SwrContext **s);
118 * in and in_count can be set to 0 to flush the last few samples out at the
121 * If more input is provided than output space then the input will be buffered.
122 * You can avoid this buffering by providing more output space than input.
123 * Convertion will run directly without copying whenever possible.
125 * @param s allocated Swr context, with parameters set
126 * @param out output buffers, only the first one need be set in case of packed audio
127 * @param out_count amount of space available for output in samples per channel
128 * @param in input buffers, only the first one need to be set in case of packed audio
129 * @param in_count number of input samples available in one channel
131 * @return number of samples output per channel, negative value on error
133 int swr_convert(struct SwrContext *s, uint8_t **out, int out_count,
134 const uint8_t **in , int in_count);
137 * Convert the next timestamp from input to output
138 * timestampe are in 1/(in_sample_rate * out_sample_rate) units.
140 * @note There are 2 slightly differently behaving modes.
141 * First is when automatic timestamp compensation is not used, (min_compensation >= FLT_MAX)
142 * in this case timestamps will be passed through with delays compensated
143 * Second is when automatic timestamp compensation is used, (min_compensation < FLT_MAX)
144 * in this case the output timestamps will match output sample numbers
146 * @param pts timstamp for the next input sample, INT64_MIN if unknown
147 * @returns the output timestamp for the next output sample
149 int64_t swr_next_pts(struct SwrContext *s, int64_t pts);
152 * Activate resampling compensation.
154 int swr_set_compensation(struct SwrContext *s, int sample_delta, int compensation_distance);
157 * Set a customized input channel mapping.
159 * @param s allocated Swr context, not yet initialized
160 * @param channel_map customized input channel mapping (array of channel
161 * indexes, -1 for a muted channel)
162 * @return AVERROR error code in case of failure.
164 int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map);
167 * Set a customized remix matrix.
169 * @param s allocated Swr context, not yet initialized
170 * @param matrix remix coefficients; matrix[i + stride * o] is
171 * the weight of input channel i in output channel o
172 * @param stride offset between lines of the matrix
173 * @return AVERROR error code in case of failure.
175 int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride);
178 * Drops the specified number of output samples.
180 int swr_drop_output(struct SwrContext *s, int count);
183 * Injects the specified number of silence samples.
185 int swr_inject_silence(struct SwrContext *s, int count);
188 * Gets the delay the next input sample will experience relative to the next output sample.
190 * Swresample can buffer data if more input has been provided than available
191 * output space, also converting between sample rates needs a delay.
192 * This function returns the sum of all such delays.
194 * @param s swr context
195 * @param base timebase in which the returned delay will be
196 * if its set to 1 the returned delay is in seconds
197 * if its set to 1000 the returned delay is in milli seconds
198 * if its set to the input sample rate then the returned delay is in input samples
199 * if its set to the output sample rate then the returned delay is in output samples
200 * an exact rounding free delay can be found by using LCM(in_sample_rate, out_sample_rate)
201 * @returns the delay in 1/base units.
203 int64_t swr_get_delay(struct SwrContext *s, int64_t base);
206 * Return the LIBSWRESAMPLE_VERSION_INT constant.
208 unsigned swresample_version(void);
211 * Return the swr build-time configuration.
213 const char *swresample_configuration(void);
216 * Return the swr license.
218 const char *swresample_license(void);
220 #endif /* SWRESAMPLE_SWRESAMPLE_H */