libavcodec/ra144enc.c File Reference

Real Audio 1.0 (14.4K) encoder. More...

#include <float.h>
#include "avcodec.h"
#include "audio_frame_queue.h"
#include "internal.h"
#include "put_bits.h"
#include "celp_filters.h"
#include "ra144.h"

Go to the source code of this file.

Functions

static av_cold int ra144_encode_close (AVCodecContext *avctx)

static av_cold int ra144_encode_init (AVCodecContext *avctx)

static int quantize (int value, const int16_t *table, unsigned int size)

Quantize a value by searching a sorted table for the element with the nearest value.

static void orthogonalize (float *v, const float *u)

Orthogonalize a vector to another vector.

static void get_match_score (float *work, const float *coefs, float *vect, const float *ortho1, const float *ortho2, const float *data, float *score, float *gain)

Calculate match score and gain of an LPC-filtered vector with respect to input data, possibly othogonalizing it to up to 2 other vectors.

static void create_adapt_vect (float *vect, const int16_t *cb, int lag)

Create a vector from the adaptive codebook at a given lag value.

static int adaptive_cb_search (const int16_t *adapt_cb, float *work, const float *coefs, float *data)

Search the adaptive codebook for the best entry and gain and remove its contribution from input data.

static void find_best_vect (float *work, const float *coefs, const int8_t cb[][BLOCKSIZE], const float *ortho1, const float *ortho2, float *data, int *idx, float *gain)

Find the best vector of a fixed codebook by applying an LPC filter to codebook entries, possibly othogonalizing them to up to 2 other vectors and matching the results with input data.

static void fixed_cb_search (float *work, const float *coefs, float *data, int cba_idx, int *cb1_idx, int *cb2_idx)

Search the two fixed codebooks for the best entry and gain.

static void ra144_encode_subblock (RA144Context *ractx, const int16_t *sblock_data, const int16_t *lpc_coefs, unsigned int rms, PutBitContext *pb)

Encode a subblock of the current frame.

static int ra144_encode_frame (AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)

Variables

AVCodec ff_ra_144_encoder

Detailed Description

Real Audio 1.0 (14.4K) encoder.

Author:: Francesco Lavra <francescolavra@interfree.it>

Definition in file ra144enc.c.

Function Documentation

static int adaptive_cb_search	(	const int16_t *	adapt_cb,
		float *	work,
		const float *	coefs,
		float *	data
	)			`[static]`

Search the adaptive codebook for the best entry and gain and remove its contribution from input data.

Parameters:

	adapt_cb	array from which the adaptive codebook is extracted
	work	array used to calculate LPC-filtered vectors
	coefs	coefficients of the LPC filter
	data	input data

Returns:: index of the best entry of the adaptive codebook

Re-calculate the filtered vector from the vector with maximum match score and remove its contribution from input data.

Definition at line 208 of file ra144enc.c.

Referenced by ra144_encode_subblock().

static void create_adapt_vect	(	float *	vect,
		const int16_t *	cb,
		int	lag
	)			`[static]`

Create a vector from the adaptive codebook at a given lag value.

Parameters:

	vect	array where vector is stored
	cb	adaptive codebook
	lag	lag value

Definition at line 185 of file ra144enc.c.

Referenced by adaptive_cb_search().

static void find_best_vect	(	float *	work,
		const float *	coefs,
		const int8_t	cb[][BLOCKSIZE],
		const float *	ortho1,
		const float *	ortho2,
		float *	data,
		int *	idx,
		float *	gain
	)			`[static]`

Find the best vector of a fixed codebook by applying an LPC filter to codebook entries, possibly othogonalizing them to up to 2 other vectors and matching the results with input data.

Parameters:

	work	array used to calculate the filtered vectors
	coefs	coefficients of the LPC filter
	cb	fixed codebook
	ortho1	first vector against which orthogonalization is performed
	ortho2	second vector against which orthogonalization is performed
	data	input data
	idx	pointer to variable where the index of the best codebook entry is returned
	gain	pointer to variable where the gain of the best codebook entry is returned

Definition at line 256 of file ra144enc.c.

Referenced by fixed_cb_search().

static void fixed_cb_search	(	float *	work,
		const float *	coefs,
		float *	data,
		int	cba_idx,
		int *	cb1_idx,
		int *	cb2_idx
	)			`[static]`

Search the two fixed codebooks for the best entry and gain.

Parameters:

	work	array used to calculate LPC-filtered vectors
	coefs	coefficients of the LPC filter
	data	input data
	cba_idx	index of the best entry of the adaptive codebook
	cb1_idx	pointer to variable where the index of the best entry of the first fixed codebook is returned
	cb2_idx	pointer to variable where the index of the best entry of the second fixed codebook is returned

The filtered vector from the adaptive codebook can be retrieved from work, because this function is called just after adaptive_cb_search().

Re-calculate the filtered vector from the vector with maximum match score and remove its contribution from input data.

Definition at line 291 of file ra144enc.c.

Referenced by ra144_encode_subblock().

static void get_match_score	(	float *	work,
		const float *	coefs,
		float *	vect,
		const float *	ortho1,
		const float *	ortho2,
		const float *	data,
		float *	score,
		float *	gain
	)			`[static]`

Calculate match score and gain of an LPC-filtered vector with respect to input data, possibly othogonalizing it to up to 2 other vectors.

Parameters:

	work	array used to calculate the filtered vector
	coefs	coefficients of the LPC filter
	vect	original vector
	ortho1	first vector against which orthogonalization is performed
	ortho2	second vector against which orthogonalization is performed
	data	input data
	score	pointer to variable where match score is returned
	gain	pointer to variable where gain is returned

Definition at line 152 of file ra144enc.c.

Referenced by adaptive_cb_search(), and find_best_vect().

static void orthogonalize	(	float *	v,
		const float *	u
	)			`[static]`

Orthogonalize a vector to another vector.

Parameters:

	v	vector to orthogonalize
	u	vector against which orthogonalization is performed

Definition at line 124 of file ra144enc.c.

Referenced by fixed_cb_search(), and get_match_score().

static int quantize	(	int	value,
		const int16_t *	table,
		unsigned int	size
	)			`[static]`

Quantize a value by searching a sorted table for the element with the nearest value.

Parameters:

	value	value to quantize
	table	array containing the quantization table
	size	size of the quantization table

Returns:: index of the quantization table corresponding to the element with the nearest value

Definition at line 99 of file ra144enc.c.

static av_cold int ra144_encode_close ( AVCodecContext * avctx ) [static]

Definition at line 38 of file ra144enc.c.

Referenced by ra144_encode_init().

static int ra144_encode_frame	(	AVCodecContext *	avctx,
		AVPacket *	avpkt,
		const AVFrame *	frame,
		int *	got_packet_ptr
	)			`[static]`

< reflection coefficients of the frame

< RMS of the reflection coefficients

Since the LPC coefficients are calculated on a frame centered over the fourth subframe, to encode a given frame, data from the next frame is needed. In each call to this function, the previous frame (whose data are saved in the encoder context) is encoded, and data from the current frame are saved in the encoder context to be used in the next function call.

TODO: apply perceptual weighting of the input speech through bandwidth expansion of the LPC filter.

The filter is unstable: use the coefficients of the previous frame.

Definition at line 440 of file ra144enc.c.

static av_cold int ra144_encode_init ( AVCodecContext * avctx ) [static]

Definition at line 50 of file ra144enc.c.

static void ra144_encode_subblock	(	RA144Context *	ractx,
		const int16_t *	sblock_data,
		const int16_t *	lpc_coefs,
		unsigned int	rms,
		PutBitContext *	pb
	)			`[static]`

Encode a subblock of the current frame.

Parameters:

	ractx	encoder context
	sblock_data	input data of the subblock
	lpc_coefs	coefficients of the LPC filter
	rms	RMS of the reflection coefficients
	pb	pointer to PutBitContext of the current frame

Calculate the zero-input response of the LPC filter and subtract it from input data.

Codebook search is performed without taking into account the contribution of the previous subblock, since it has been just subtracted from input data.

The filtered vector from the adaptive codebook can be retrieved from work, see implementation of adaptive_cb_search().

Definition at line 340 of file ra144enc.c.

Referenced by ra144_encode_frame().

Variable Documentation

AVCodec ff_ra_144_encoder

Initial value:

 {
    .name           = "real_144",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_RA_144,
    .priv_data_size = sizeof(RA144Context),
    .init           = ra144_encode_init,
    .encode2        = ra144_encode_frame,
    .close          = ra144_encode_close,
    .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_SMALL_LAST_FRAME,
    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
                                                     AV_SAMPLE_FMT_NONE },
    .long_name      = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
}

Definition at line 555 of file ra144enc.c.


Functions
static av_cold int	ra144_encode_close (AVCodecContext *avctx)
static av_cold int	ra144_encode_init (AVCodecContext *avctx)
static int	quantize (int value, const int16_t *table, unsigned int size)
	Quantize a value by searching a sorted table for the element with the nearest value.
static void	orthogonalize (float v, const float u)
	Orthogonalize a vector to another vector.
static void	get_match_score (float work, const float coefs, float vect, const float ortho1, const float ortho2, const float data, float score, float gain)
	Calculate match score and gain of an LPC-filtered vector with respect to input data, possibly othogonalizing it to up to 2 other vectors.
static void	create_adapt_vect (float vect, const int16_t cb, int lag)
	Create a vector from the adaptive codebook at a given lag value.
static int	adaptive_cb_search (const int16_t adapt_cb, float work, const float coefs, float data)
	Search the adaptive codebook for the best entry and gain and remove its contribution from input data.
static void	find_best_vect (float work, const float coefs, const int8_t cb[][BLOCKSIZE], const float ortho1, const float ortho2, float data, int idx, float *gain)
	Find the best vector of a fixed codebook by applying an LPC filter to codebook entries, possibly othogonalizing them to up to 2 other vectors and matching the results with input data.
static void	fixed_cb_search (float work, const float coefs, float data, int cba_idx, int cb1_idx, int *cb2_idx)
	Search the two fixed codebooks for the best entry and gain.
static void	ra144_encode_subblock (RA144Context ractx, const int16_t sblock_data, const int16_t lpc_coefs, unsigned int rms, PutBitContext pb)
	Encode a subblock of the current frame.
static int	ra144_encode_frame (AVCodecContext avctx, AVPacket avpkt, const AVFrame frame, int got_packet_ptr)
Variables
AVCodec	ff_ra_144_encoder