libavcodec/resample.c File Reference

samplerate conversion for both audio and video More...

#include "avcodec.h"
#include "audioconvert.h"
#include "libavutil/opt.h"
#include "libavutil/samplefmt.h"

Go to the source code of this file.

Data Structures
struct	ReSampleContext
Defines
#define	MAX_CHANNELS   8
#define	SUPPORT_RESAMPLE(ch1, ch2, ch3, ch4, ch5, ch6, ch7, ch8)   ch8<<7 | ch7<<6 | ch6<<5 | ch5<<4 | ch4<<3 | ch3<<2 | ch2<<1 | ch1<<0
Functions
static const char *	context_to_name (void *ptr)
static void	stereo_to_mono (short *output, short *input, int n1)
static void	mono_to_stereo (short *output, short *input, int n1)
static void	surround_to_stereo (short **output, short *input, int channels, int samples)
static void	deinterleave (short **output, short *input, int channels, int samples)
static void	interleave (short *output, short **input, int channels, int samples)
static void	ac3_5p1_mux (short *output, short *input1, short *input2, int n)
ReSampleContext *	av_audio_resample_init (int output_channels, int input_channels, int output_rate, int input_rate, enum AVSampleFormat sample_fmt_out, enum AVSampleFormat sample_fmt_in, int filter_length, int log2_phase_count, int linear, double cutoff)
	Initialize audio resampling context.
int	audio_resample (ReSampleContext *s, short *output, short *input, int nb_samples)
void	audio_resample_close (ReSampleContext *s)
	Free resample context.
Variables
static const AVOption	options [] = {{NULL}}
static const AVClass	audioresample_context_class
static const uint8_t	supported_resampling [MAX_CHANNELS]

---

Detailed Description

samplerate conversion for both audio and video

Definition in file resample.c.

---

Define Documentation

#define MAX_CHANNELS   8

Definition at line 32 of file resample.c.

#define SUPPORT_RESAMPLE	(	ch1,
		ch2,
		ch3,
		ch4,
		ch5,
		ch6,
		ch7,
		ch8		)	ch8<<7 | ch7<<6 | ch6<<5 | ch5<<4 | ch4<<3 | ch3<<2 | ch2<<1 | ch1<<0

Definition at line 183 of file resample.c.

---

Function Documentation

static void ac3_5p1_mux	(	short *	output,
		short *	input1,
		short *	input2,
		int	n
	)			[static]

Definition at line 166 of file resample.c.

Referenced by audio_resample().

int audio_resample	(	ReSampleContext *	s,
		short *	output,
		short *	input,
		int	nb_samples
	)

Definition at line 279 of file resample.c.

Referenced by do_audio_out().

void audio_resample_close

(

ReSampleContext *

s

)

Free resample context.

Parameters:

s

a non-NULL pointer to a resample context previously created with av_audio_resample_init()

Definition at line 415 of file resample.c.

Referenced by do_audio_out(), and transcode().

ReSampleContext* av_audio_resample_init	(	int	output_channels,
		int	input_channels,
		int	output_rate,
		int	input_rate,
		enum AVSampleFormat	sample_fmt_out,
		enum AVSampleFormat	sample_fmt_in,
		int	filter_length,
		int	log2_phase_count,
		int	linear,
		double	cutoff
	)

Initialize audio resampling context.

Parameters:

	output_channels	number of output channels
	input_channels	number of input channels
	output_rate	output sample rate
	input_rate	input sample rate
	sample_fmt_out	requested output sample format
	sample_fmt_in	input sample format
	filter_length	length of each FIR filter in the filterbank relative to the cutoff frequency
	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

Returns:

allocated ReSampleContext, NULL if error occured

Definition at line 198 of file resample.c.

Referenced by do_audio_out().

static const char* context_to_name

(

void *

ptr

)

[static]

Definition at line 36 of file resample.c.

static void deinterleave	(	short **	output,
		short *	input,
		int	channels,
		int	samples
	)			[static]

Definition at line 144 of file resample.c.

Referenced by audio_resample(), and filter_samples().

static void interleave	(	short *	output,
		short **	input,
		int	channels,
		int	samples
	)			[static]

Definition at line 155 of file resample.c.

static void mono_to_stereo	(	short *	output,
		short *	input,
		int	n1
	)			[static]

Definition at line 86 of file resample.c.

Referenced by audio_resample().

static void stereo_to_mono	(	short *	output,
		short *	input,
		int	n1
	)			[static]

Definition at line 61 of file resample.c.

Referenced by audio_resample().

static void surround_to_stereo	(	short **	output,
		short *	input,
		int	channels,
		int	samples
	)			[static]

Definition at line 118 of file resample.c.

Referenced by audio_resample().

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Variable Documentation

const AVClass audioresample_context_class [static]

Initial value:

 {
    "ReSampleContext", context_to_name, options, LIBAVUTIL_VERSION_INT
}

Definition at line 42 of file resample.c.

const AVOption options[] = {{NULL}} [static]

Definition at line 41 of file resample.c.

const uint8_t supported_resampling[MAX_CHANNELS] [static]

Initial value:

 {
    
    SUPPORT_RESAMPLE(1, 1, 0, 0, 0, 0, 0, 0), 
    SUPPORT_RESAMPLE(1, 1, 0, 0, 0, 1, 0, 0), 
    SUPPORT_RESAMPLE(0, 0, 1, 0, 0, 0, 0, 0), 
    SUPPORT_RESAMPLE(0, 0, 0, 1, 0, 0, 0, 0), 
    SUPPORT_RESAMPLE(0, 0, 0, 0, 1, 0, 0, 0), 
    SUPPORT_RESAMPLE(0, 1, 0, 0, 0, 1, 0, 0), 
    SUPPORT_RESAMPLE(0, 0, 0, 0, 0, 0, 1, 0), 
    SUPPORT_RESAMPLE(0, 0, 0, 0, 0, 0, 0, 1), 
}

Definition at line 186 of file resample.c.

Referenced by av_audio_resample_init().