hvirtual/quicktime/ffmpeg/libavcodec/alac.c File Reference

#include "avcodec.h"
#include "bitstream.h"

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Data Structures

struct ALACContext

Defines

#define ALAC_EXTRADATA_SIZE 36

#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))

#define SIGN_ONLY(v)

Functions

static void allocate_buffers (ALACContext *alac)

void alac_set_info (ALACContext *alac)

static int count_leading_zeros (int32_t input)

void bastardized_rice_decompress (ALACContext *alac, int32_t *output_buffer, int output_size, int readsamplesize, int rice_initialhistory, int rice_kmodifier, int rice_historymult, int rice_kmodifier_mask)

static void predictor_decompress_fir_adapt (int32_t *error_buffer, int32_t *buffer_out, int output_size, int readsamplesize, int16_t *predictor_coef_table, int predictor_coef_num, int predictor_quantitization)

void deinterlace_16 (int32_t *buffer_a, int32_t *buffer_b, int16_t *buffer_out, int numchannels, int numsamples, uint8_t interlacing_shift, uint8_t interlacing_leftweight)

static int alac_decode_frame (AVCodecContext *avctx, void *outbuffer, int *outputsize, uint8_t *inbuffer, int input_buffer_size)

static int alac_decode_init (AVCodecContext *avctx)

static int alac_decode_close (AVCodecContext *avctx)

Variables

AVCodec alac_decoder

Detailed Description

ALAC (Apple Lossless Audio Codec) decoder

Author:: 2005 David Hammerton

For more information on the ALAC format, visit: http://crazney.net/programs/itunes/alac.html

Note: This decoder expects a 36- (0x24-)byte QuickTime atom to be passed through the extradata[_size] fields. This atom is tacked onto the end of an 'alac' stsd atom and has the following format: bytes 0-3 atom size (0x24), big-endian bytes 4-7 atom type ('alac', not the 'alac' tag from start of stsd) bytes 8-35 data bytes needed by decoder

Definition in file alac.c.

Define Documentation

#define ALAC_EXTRADATA_SIZE 36

Definition at line 41 of file alac.c.

Referenced by alac_decode_frame().

#define SIGN_EXTENDED32	(	val,
		bits		)	((val << (32 - bits)) >> (32 - bits))

Definition at line 255 of file alac.c.

Referenced by alac_decode_frame(), and predictor_decompress_fir_adapt().

#define SIGN_ONLY ( v )

Value:

((v < 0) ? (-1) : \
                                ((v > 0) ? (1) : \
                                           (0)))

Definition at line 257 of file alac.c.

Referenced by predictor_decompress_fir_adapt().

Function Documentation

static int alac_decode_close ( AVCodecContext * avctx ) [static]

Definition at line 811 of file alac.c.

References av_free(), ALACContext::outputsamples_buffer_a, ALACContext::outputsamples_buffer_b, ALACContext::predicterror_buffer_a, ALACContext::predicterror_buffer_b, and AVCodecContext::priv_data.

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static int alac_decode_frame	(	AVCodecContext *	avctx,
		void *	outbuffer,
		int *	outputsize,
		uint8_t *	inbuffer,
		int	input_buffer_size
	)			`[static]`

Definition at line 431 of file alac.c.

References ALAC_EXTRADATA_SIZE, alac_set_info(), av_log(), AV_LOG_ERROR, ALACContext::avctx, bastardized_rice_decompress(), be2me_16, ALACContext::bytespersample, ALACContext::context_initialized, deinterlace_16(), AVCodecContext::extradata_size, ALACContext::gb, get_bits(), init_get_bits(), NULL, ALACContext::numchannels, ALACContext::outputsamples_buffer_a, ALACContext::outputsamples_buffer_b, ALACContext::predicterror_buffer_a, ALACContext::predicterror_buffer_b, predictor_decompress_fir_adapt(), AVCodecContext::priv_data, ALACContext::setinfo_max_samples_per_frame, ALACContext::setinfo_rice_historymult, ALACContext::setinfo_rice_initialhistory, ALACContext::setinfo_rice_kmodifier, ALACContext::setinfo_sample_size, and SIGN_EXTENDED32.

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static int alac_decode_init ( AVCodecContext * avctx ) [static]

Definition at line 798 of file alac.c.

References ALACContext::avctx, AVCodecContext::bits_per_sample, ALACContext::bytespersample, AVCodecContext::channels, ALACContext::context_initialized, ALACContext::numchannels, AVCodecContext::priv_data, and ALACContext::samplesize.

void alac_set_info ( ALACContext * alac )

Definition at line 87 of file alac.c.

References allocate_buffers(), ALACContext::avctx, BE_16, BE_32, AVCodecContext::extradata, ALACContext::setinfo_7a, ALACContext::setinfo_7f, ALACContext::setinfo_80, ALACContext::setinfo_82, ALACContext::setinfo_86, ALACContext::setinfo_8a_rate, ALACContext::setinfo_max_samples_per_frame, ALACContext::setinfo_rice_historymult, ALACContext::setinfo_rice_initialhistory, ALACContext::setinfo_rice_kmodifier, and ALACContext::setinfo_sample_size.

Referenced by alac_decode_frame().

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static void allocate_buffers ( ALACContext * alac ) [static]

Definition at line 78 of file alac.c.

References av_malloc(), ALACContext::outputsamples_buffer_a, ALACContext::outputsamples_buffer_b, ALACContext::predicterror_buffer_a, ALACContext::predicterror_buffer_b, and ALACContext::setinfo_max_samples_per_frame.

Referenced by alac_set_info(), metadata_streaminfo(), and shorten_decode_frame().

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void bastardized_rice_decompress	(	ALACContext *	alac,
		int32_t *	output_buffer,
		int	output_size,
		int	readsamplesize,
		int	rice_initialhistory,
		int	rice_kmodifier,
		int	rice_historymult,
		int	rice_kmodifier_mask
	)

Definition at line 128 of file alac.c.

References count_leading_zeros(), ALACContext::gb, get_bits(), get_bits1(), and show_bits().

Referenced by alac_decode_frame().

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static int count_leading_zeros ( int32_t input ) [static]

Definition at line 118 of file alac.c.

Referenced by bastardized_rice_decompress().

void deinterlace_16	(	int32_t *	buffer_a,
		int32_t *	buffer_b,
		int16_t *	buffer_out,
		int	numchannels,
		int	numsamples,
		uint8_t	interlacing_shift,
		uint8_t	interlacing_leftweight
	)

Definition at line 388 of file alac.c.

Referenced by alac_decode_frame().

static void predictor_decompress_fir_adapt	(	int32_t *	error_buffer,
		int32_t *	buffer_out,
		int	output_size,
		int	readsamplesize,
		int16_t *	predictor_coef_table,
		int	predictor_coef_num,
		int	predictor_quantitization
	)			`[static]`

Definition at line 262 of file alac.c.

References memcpy, SIGN_EXTENDED32, and SIGN_ONLY.

Referenced by alac_decode_frame().

Variable Documentation

AVCodec alac_decoder

Initial value:

 {
    "alac",
    CODEC_TYPE_AUDIO,
    CODEC_ID_ALAC,
    sizeof(ALACContext),
    alac_decode_init,
    NULL,
    alac_decode_close,
    alac_decode_frame,
}

Definition at line 824 of file alac.c.

Referenced by avcodec_register_all().


Data Structures
struct	ALACContext
Defines
#define	ALAC_EXTRADATA_SIZE 36
#define	SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
#define	SIGN_ONLY(v)
Functions
static void	allocate_buffers (ALACContext *alac)
void	alac_set_info (ALACContext *alac)
static int	count_leading_zeros (int32_t input)
void	bastardized_rice_decompress (ALACContext alac, int32_t output_buffer, int output_size, int readsamplesize, int rice_initialhistory, int rice_kmodifier, int rice_historymult, int rice_kmodifier_mask)
static void	predictor_decompress_fir_adapt (int32_t error_buffer, int32_t buffer_out, int output_size, int readsamplesize, int16_t *predictor_coef_table, int predictor_coef_num, int predictor_quantitization)
void	deinterlace_16 (int32_t buffer_a, int32_t buffer_b, int16_t *buffer_out, int numchannels, int numsamples, uint8_t interlacing_shift, uint8_t interlacing_leftweight)
static int	alac_decode_frame (AVCodecContext avctx, void outbuffer, int outputsize, uint8_t inbuffer, int input_buffer_size)
static int	alac_decode_init (AVCodecContext *avctx)
static int	alac_decode_close (AVCodecContext *avctx)
Variables
AVCodec	alac_decoder