resample.c File Reference

audio resampling More...

#include "libavutil/avassert.h"
#include "resample.h"

Go to the source code of this file.

Functions
static double	eval_poly (const double *coeff, int size, double x)
static double	bessel (double x)
	0th order modified bessel function of the first kind. More...
static int	build_filter (ResampleContext *c, void *filter, double factor, int tap_count, int alloc, int phase_count, int scale, int filter_type, double kaiser_beta)
	builds a polyphase filterbank. More...
static void	resample_free (ResampleContext **cc)
static ResampleContext *	resample_init (ResampleContext *c, int out_rate, int in_rate, int filter_size, int phase_shift, int linear, double cutoff0, enum AVSampleFormat format, enum SwrFilterType filter_type, double kaiser_beta, double precision, int cheby, int exact_rational)
static int	rebuild_filter_bank_with_compensation (ResampleContext *c)
static int	set_compensation (ResampleContext *c, int sample_delta, int compensation_distance)
static int	multiple_resample (ResampleContext *c, AudioData *dst, int dst_size, AudioData *src, int src_size, int *consumed)
static int64_t	get_delay (struct SwrContext *s, int64_t base)
static int64_t	get_out_samples (struct SwrContext *s, int in_samples)
static int	resample_flush (struct SwrContext *s)
static int	invert_initial_buffer (ResampleContext *c, AudioData *dst, const AudioData *src, int in_count, int *out_idx, int *out_sz)

Variables
struct Resampler const	swri_resampler

Detailed Description

audio resampling

Author

Michael Niedermayer micha.nosp@m.elni.nosp@m.@gmx..nosp@m.at

Definition in file resample.c.

Function Documentation

eval_poly()

static double eval_poly ( const double *  coeff, int  size, double  x  )

inlinestatic

Definition at line 32 of file resample.c.

Referenced by bessel().

bessel()

static double bessel ( double  x )

static

0th order modified bessel function of the first kind.

Algorithm taken from the Boost project, source: https://searchcode.com/codesearch/view/14918379/ Use, modification and distribution are subject to the Boost Software License, Version 1.0 (see notice below). Boost Software License - Version 1.0 - August 17th, 2003 Permission is hereby granted, free of charge, to any person or organization obtaining a copy of the software and accompanying documentation covered by this license (the "Software") to use, reproduce, display, distribute, execute, and transmit the Software, and to prepare derivative works of the Software, and to permit third-parties to whom the Software is furnished to do so, all subject to the following:

The copyright notices in the Software and this entire statement, including the above license grant, this restriction and the following disclaimer, must be included in all copies of the Software, in whole or in part, and all derivative works of the Software, unless such copies or derivative works are solely in the form of machine-executable object code generated by a source language processor.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Definition at line 72 of file resample.c.

Referenced by build_filter().

build_filter()

static int build_filter ( ResampleContext *  c, void *  filter, double  factor, int  tap_count, int  alloc, int  phase_count, int  scale, int  filter_type, double  kaiser_beta  )

static

builds a polyphase filterbank.

Parameters

factor	resampling factor
scale	wanted sum of coefficients for each filter
filter_type	filter type
kaiser_beta	kaiser window beta

Returns

0 on success, negative on error

Definition at line 144 of file resample.c.

Referenced by rebuild_filter_bank_with_compensation(), and resample_init().

resample_free()

static void resample_free ( ResampleContext **  cc )

static

Definition at line 279 of file resample.c.

Referenced by resample_init().

resample_init()

static ResampleContext* resample_init ( ResampleContext *  c, int  out_rate, int  in_rate, int  filter_size, int  phase_shift, int  linear, double  cutoff0, enum AVSampleFormat  format, enum SwrFilterType  filter_type, double  kaiser_beta, double  precision, int  cheby, int  exact_rational  )

static

Definition at line 287 of file resample.c.

rebuild_filter_bank_with_compensation()

static int rebuild_filter_bank_with_compensation ( ResampleContext *  c )

static

Definition at line 383 of file resample.c.

Referenced by set_compensation().

set_compensation()

static int set_compensation ( ResampleContext *  c, int  sample_delta, int  compensation_distance  )

static

Definition at line 431 of file resample.c.

multiple_resample()

static int multiple_resample ( ResampleContext *  c, AudioData *  dst, int  dst_size, AudioData *  src, int  src_size, int *  consumed  )

static

Definition at line 452 of file resample.c.

get_delay()

static int64_t get_delay ( struct SwrContext *  s, int64_t  base  )

static

Definition at line 517 of file resample.c.

get_out_samples()

static int64_t get_out_samples ( struct SwrContext *  s, int  in_samples  )

static

Definition at line 527 of file resample.c.

resample_flush()

static int resample_flush ( struct SwrContext *  s )

static

Definition at line 546 of file resample.c.

invert_initial_buffer()

static int invert_initial_buffer ( ResampleContext *  c, AudioData *  dst, const AudioData *  src, int  in_count, int *  out_idx, int *  out_sz  )

static

Definition at line 566 of file resample.c.

Variable Documentation

swri_resampler

struct Resampler const swri_resampler

Initial value:

={
  resample_init,
  resample_free,
  multiple_resample,
  resample_flush,
  set_compensation,
  get_delay,
  invert_initial_buffer,
  get_out_samples,
}

Definition at line 613 of file resample.c.

Referenced by swr_init().