2 * Copyright (C) 2011 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
30 #include "libavutil/samplefmt.h"
32 #define LIBSWRESAMPLE_VERSION_MAJOR 0
33 #define LIBSWRESAMPLE_VERSION_MINOR 15
34 #define LIBSWRESAMPLE_VERSION_MICRO 100
36 #define LIBSWRESAMPLE_VERSION_INT AV_VERSION_INT(LIBSWRESAMPLE_VERSION_MAJOR, \
37 LIBSWRESAMPLE_VERSION_MINOR, \
38 LIBSWRESAMPLE_VERSION_MICRO)
40 #if LIBSWRESAMPLE_VERSION_MAJOR < 1
41 #define SWR_CH_MAX 32 ///< Maximum number of channels
44 #define SWR_FLAG_RESAMPLE 1 ///< Force resampling even if equal sample rate
45 //TODO use int resample ?
46 //long term TODO can we enable this dynamically?
50 SWR_DITHER_RECTANGULAR,
51 SWR_DITHER_TRIANGULAR,
52 SWR_DITHER_TRIANGULAR_HIGHPASS,
53 SWR_DITHER_NB, ///< not part of API/ABI
56 /** Resampling Filter Types */
58 SWR_FILTER_TYPE_CUBIC, /**< Cubic */
59 SWR_FILTER_TYPE_BLACKMAN_NUTTALL, /**< Blackman Nuttall Windowed Sinc */
60 SWR_FILTER_TYPE_KAISER, /**< Kaiser Windowed Sinc */
63 typedef struct SwrContext SwrContext;
66 * Get the AVClass for swrContext. It can be used in combination with
67 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
71 const AVClass *swr_get_class(void);
74 * Allocate SwrContext.
76 * If you use this function you will need to set the parameters (manually or
77 * with swr_alloc_set_opts()) before calling swr_init().
79 * @see swr_alloc_set_opts(), swr_init(), swr_free()
80 * @return NULL on error, allocated context otherwise
82 struct SwrContext *swr_alloc(void);
85 * Initialize context after user parameters have been set.
87 * @return AVERROR error code in case of failure.
89 int swr_init(struct SwrContext *s);
92 * Allocate SwrContext if needed and set/reset common parameters.
94 * This function does not require s to be allocated with swr_alloc(). On the
95 * other hand, swr_alloc() can use swr_alloc_set_opts() to set the parameters
96 * on the allocated context.
98 * @param s Swr context, can be NULL
99 * @param out_ch_layout output channel layout (AV_CH_LAYOUT_*)
100 * @param out_sample_fmt output sample format (AV_SAMPLE_FMT_*).
101 * @param out_sample_rate output sample rate (frequency in Hz)
102 * @param in_ch_layout input channel layout (AV_CH_LAYOUT_*)
103 * @param in_sample_fmt input sample format (AV_SAMPLE_FMT_*).
104 * @param in_sample_rate input sample rate (frequency in Hz)
105 * @param log_offset logging level offset
106 * @param log_ctx parent logging context, can be NULL
108 * @see swr_init(), swr_free()
109 * @return NULL on error, allocated context otherwise
111 struct SwrContext *swr_alloc_set_opts(struct SwrContext *s,
112 int64_t out_ch_layout, enum AVSampleFormat out_sample_fmt, int out_sample_rate,
113 int64_t in_ch_layout, enum AVSampleFormat in_sample_fmt, int in_sample_rate,
114 int log_offset, void *log_ctx);
117 * Free the given SwrContext and set the pointer to NULL.
119 void swr_free(struct SwrContext **s);
124 * in and in_count can be set to 0 to flush the last few samples out at the
127 * If more input is provided than output space then the input will be buffered.
128 * You can avoid this buffering by providing more output space than input.
129 * Convertion will run directly without copying whenever possible.
131 * @param s allocated Swr context, with parameters set
132 * @param out output buffers, only the first one need be set in case of packed audio
133 * @param out_count amount of space available for output in samples per channel
134 * @param in input buffers, only the first one need to be set in case of packed audio
135 * @param in_count number of input samples available in one channel
137 * @return number of samples output per channel, negative value on error
139 int swr_convert(struct SwrContext *s, uint8_t **out, int out_count,
140 const uint8_t **in , int in_count);
143 * Convert the next timestamp from input to output
144 * timestampe are in 1/(in_sample_rate * out_sample_rate) units.
146 * @note There are 2 slightly differently behaving modes.
147 * First is when automatic timestamp compensation is not used, (min_compensation >= FLT_MAX)
148 * in this case timestamps will be passed through with delays compensated
149 * Second is when automatic timestamp compensation is used, (min_compensation < FLT_MAX)
150 * in this case the output timestamps will match output sample numbers
152 * @param pts timstamp for the next input sample, INT64_MIN if unknown
153 * @returns the output timestamp for the next output sample
155 int64_t swr_next_pts(struct SwrContext *s, int64_t pts);
158 * Activate resampling compensation.
160 int swr_set_compensation(struct SwrContext *s, int sample_delta, int compensation_distance);
163 * Set a customized input channel mapping.
165 * @param s allocated Swr context, not yet initialized
166 * @param channel_map customized input channel mapping (array of channel
167 * indexes, -1 for a muted channel)
168 * @return AVERROR error code in case of failure.
170 int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map);
173 * Set a customized remix matrix.
175 * @param s allocated Swr context, not yet initialized
176 * @param matrix remix coefficients; matrix[i + stride * o] is
177 * the weight of input channel i in output channel o
178 * @param stride offset between lines of the matrix
179 * @return AVERROR error code in case of failure.
181 int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride);
184 * Drops the specified number of output samples.
186 int swr_drop_output(struct SwrContext *s, int count);
189 * Injects the specified number of silence samples.
191 int swr_inject_silence(struct SwrContext *s, int count);
194 * Gets the delay the next input sample will experience relative to the next output sample.
196 * Swresample can buffer data if more input has been provided than available
197 * output space, also converting between sample rates needs a delay.
198 * This function returns the sum of all such delays.
200 * @param s swr context
201 * @param base timebase in which the returned delay will be
202 * if its set to 1 the returned delay is in seconds
203 * if its set to 1000 the returned delay is in milli seconds
204 * if its set to the input sample rate then the returned delay is in input samples
205 * if its set to the output sample rate then the returned delay is in output samples
206 * an exact rounding free delay can be found by using LCM(in_sample_rate, out_sample_rate)
207 * @returns the delay in 1/base units.
209 int64_t swr_get_delay(struct SwrContext *s, int64_t base);
212 * Return the LIBSWRESAMPLE_VERSION_INT constant.
214 unsigned swresample_version(void);
217 * Return the swr build-time configuration.
219 const char *swresample_configuration(void);
222 * Return the swr license.
224 const char *swresample_license(void);