#include "avcodec.h"
#include "dsputil.h"
Go to the source code of this file.
Data Structures | |
| struct | AVResampleContext |
Defines | |
| #define | FILTER_SHIFT 15 |
| #define | FELEM int16_t |
| #define | FELEM2 int32_t |
| #define | FELEML int64_t |
| #define | FELEM_MAX INT16_MAX |
| #define | FELEM_MIN INT16_MIN |
| #define | WINDOW_TYPE 9 |
Functions | |
| static double | bessel (double x) |
| 0th order modified bessel function of the first kind. | |
| static int | build_filter (FELEM *filter, double factor, int tap_count, int phase_count, int scale, int type) |
| builds a polyphase filterbank. | |
| AVResampleContext * | av_resample_init (int out_rate, int in_rate, int filter_size, int phase_shift, int linear, double cutoff) |
| Initialize an audio resampler. | |
| void | av_resample_close (AVResampleContext *c) |
| void | av_resample_compensate (AVResampleContext *c, int sample_delta, int compensation_distance) |
| Compensate samplerate/timestamp drift. | |
| int | av_resample (AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx) |
| Resample an array of samples using a previously configured context. | |
Definition in file resample2.c.
| #define FELEM int16_t |
| #define FELEM2 int32_t |
| #define FELEM_MAX INT16_MAX |
| #define FELEM_MIN INT16_MIN |
| #define FELEML int64_t |
| #define FILTER_SHIFT 15 |
Definition at line 32 of file resample2.c.
Referenced by av_resample(), av_resample_init(), and build_filter().
| #define WINDOW_TYPE 9 |
| int av_resample | ( | struct AVResampleContext * | c, | |
| short * | dst, | |||
| short * | src, | |||
| int * | consumed, | |||
| int | src_size, | |||
| int | dst_size, | |||
| int | update_ctx | |||
| ) |
Resample an array of samples using a previously configured context.
| src | an array of unconsumed samples | |
| consumed | the number of samples of src which have been consumed are returned here | |
| src_size | the number of unconsumed samples available | |
| dst_size | the amount of space in samples available in dst | |
| update_ctx | If this is 0 then the context will not be modified, that way several channels can be resampled with the same context. |
Definition at line 234 of file resample2.c.
Referenced by audio_resample().
| void av_resample_close | ( | AVResampleContext * | c | ) |
| void av_resample_compensate | ( | struct AVResampleContext * | c, | |
| int | sample_delta, | |||
| int | compensation_distance | |||
| ) |
Compensate samplerate/timestamp drift.
The compensation is done by changing the resampler parameters, so no audible clicks or similar distortions occur
| compensation_distance | distance in output samples over which the compensation should be performed | |
| sample_delta | number of output samples which should be output less |
note, due to rounding the actual compensation might be slightly different, especially if the compensation_distance is large and the in_rate used during init is small
Definition at line 228 of file resample2.c.
Referenced by av_resample(), and do_audio_out().
| AVResampleContext* av_resample_init | ( | int | out_rate, | |
| int | in_rate, | |||
| int | filter_length, | |||
| int | log2_phase_count, | |||
| int | linear, | |||
| double | cutoff | |||
| ) | [read] |
Initialize an audio resampler.
Note, if either rate is not an integer then simply scale both rates up so they are.
| filter_length | length of each FIR filter in the filterbank relative to the cutoff freq | |
| log2_phase_count | log2 of the number of entries in the polyphase filterbank | |
| linear | If 1 then the used FIR filter will be linearly interpolated between the 2 closest, if 0 the closest will be used | |
| cutoff | cutoff frequency, 1.0 corresponds to half the output sampling rate |
Definition at line 189 of file resample2.c.
Referenced by av_audio_resample_init().
| static double bessel | ( | double | x | ) | [static] |
0th order modified bessel function of the first kind.
Definition at line 77 of file resample2.c.
Referenced by build_filter(), and ff_kbd_window_init().
| static int build_filter | ( | FELEM * | filter, | |
| double | factor, | |||
| int | tap_count, | |||
| int | phase_count, | |||
| int | scale, | |||
| int | type | |||
| ) | [static] |
builds a polyphase filterbank.
| factor | resampling factor | |
| scale | wanted sum of coefficients for each filter | |
| type | 0->cubic, 1->blackman nuttall windowed sinc, 2..16->kaiser windowed sinc beta=2..16 |
Definition at line 99 of file resample2.c.
Referenced by av_resample_init().
1.5.8