atrac1.c File Reference

ATRAC1 compatible decoder. More...

#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include "libavutil/float_dsp.h"
#include "avcodec.h"
#include "get_bits.h"
#include "fft.h"
#include "internal.h"
#include "sinewin.h"
#include "atrac.h"
#include "atrac1data.h"

Go to the source code of this file.

Data Structures
struct	AT1SUCtx
	Sound unit struct, one unit is used per channel. More...
struct	AT1Ctx
	The atrac1 context, holds all needed parameters for decoding. More...

Macros
#define	AT1_MAX_BFU   52
	max number of block floating units in a sound unit
#define	AT1_SU_SIZE   212
	number of bytes in a sound unit
#define	AT1_SU_SAMPLES   512
	number of samples in a sound unit
#define	AT1_FRAME_SIZE   AT1_SU_SIZE * 2
#define	AT1_SU_MAX_BITS   AT1_SU_SIZE * 8
#define	AT1_MAX_CHANNELS   2
#define	AT1_QMF_BANDS   3
#define	IDX_LOW_BAND   0
#define	IDX_MID_BAND   1
#define	IDX_HIGH_BAND   2

Functions
static void	at1_imdct (AT1Ctx *q, float *spec, float *out, int nbits, int rev_spec)
static int	at1_imdct_block (AT1SUCtx *su, AT1Ctx *q)
static int	at1_parse_bsm (GetBitContext *gb, int log2_block_cnt[AT1_QMF_BANDS])
	Parse the block size mode byte.
static int	at1_unpack_dequant (GetBitContext *gb, AT1SUCtx *su, float spec[AT1_SU_SAMPLES])
static void	at1_subband_synthesis (AT1Ctx *q, AT1SUCtx *su, float *pOut)
static int	atrac1_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
static av_cold int	atrac1_decode_end (AVCodecContext *avctx)
static av_cold int	atrac1_decode_init (AVCodecContext *avctx)

Variables
static const uint16_t	samples_per_band [3] = {128, 128, 256}
	size of the transform in samples in the long mode for each QMF band
static const uint8_t	mdct_long_nbits [3] = {7, 7, 8}
AVCodec	ff_atrac1_decoder

Detailed Description

ATRAC1 compatible decoder.

This decoder handles raw ATRAC1 data and probably SDDS data.

Definition in file atrac1.c.

Macro Definition Documentation

#define AT1_MAX_BFU   52

max number of block floating units in a sound unit

Definition at line 45 of file atrac1.c.

Referenced by at1_unpack_dequant().

#define AT1_SU_SIZE   212

number of bytes in a sound unit

Definition at line 46 of file atrac1.c.

#define AT1_SU_SAMPLES   512

number of samples in a sound unit

Definition at line 47 of file atrac1.c.

Referenced by atrac1_decode_frame().

#define AT1_FRAME_SIZE   AT1_SU_SIZE * 2

Definition at line 48 of file atrac1.c.

#define AT1_SU_MAX_BITS   AT1_SU_SIZE * 8

Definition at line 49 of file atrac1.c.

Referenced by at1_unpack_dequant().

#define AT1_MAX_CHANNELS   2

Definition at line 50 of file atrac1.c.

Referenced by atrac1_decode_init().

#define AT1_QMF_BANDS   3

Definition at line 52 of file atrac1.c.

Referenced by at1_imdct_block(), and at1_unpack_dequant().

#define IDX_LOW_BAND   0

Definition at line 53 of file atrac1.c.

#define IDX_MID_BAND   1

Definition at line 54 of file atrac1.c.

#define IDX_HIGH_BAND   2

Definition at line 55 of file atrac1.c.

Referenced by at1_parse_bsm().

Function Documentation

static void at1_imdct ( AT1Ctx *  q, float *  spec, float *  out, int  nbits, int  rev_spec  )

static

Definition at line 91 of file atrac1.c.

Referenced by at1_imdct_block().

static int at1_imdct_block ( AT1SUCtx *  su, AT1Ctx *  q  )

static

Definition at line 106 of file atrac1.c.

Referenced by atrac1_decode_frame().

static int at1_parse_bsm ( GetBitContext *  gb, int  log2_block_cnt[AT1_QMF_BANDS]  )

static

Parse the block size mode byte.

Definition at line 167 of file atrac1.c.

Referenced by atrac1_decode_frame().

static int at1_unpack_dequant ( GetBitContext *  gb, AT1SUCtx *  su, float  spec[AT1_SU_SAMPLES]  )

static

< the word length indexes for each BFU

< the scalefactor indexes for each BFU

Definition at line 190 of file atrac1.c.

Referenced by atrac1_decode_frame().

static void at1_subband_synthesis ( AT1Ctx *  q, AT1SUCtx *  su, float *  pOut  )

static

Definition at line 255 of file atrac1.c.

Referenced by atrac1_decode_frame().

static int atrac1_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame_ptr, AVPacket *  avpkt  )

static

Definition at line 272 of file atrac1.c.

static av_cold int atrac1_decode_end ( AVCodecContext *  avctx )

static

Definition at line 319 of file atrac1.c.

Referenced by atrac1_decode_init().

static av_cold int atrac1_decode_init ( AVCodecContext *  avctx )

static

Definition at line 333 of file atrac1.c.

Variable Documentation

const uint16_t samples_per_band[3] = {128, 128, 256}

static

size of the transform in samples in the long mode for each QMF band

Definition at line 87 of file atrac1.c.

Referenced by at1_imdct_block().

const uint8_t mdct_long_nbits[3] = {7, 7, 8}

static

Definition at line 88 of file atrac1.c.

Referenced by at1_imdct_block().

AVCodec ff_atrac1_decoder

Initial value:

= {
    .name           = "atrac1",
    .long_name      = NULL_IF_CONFIG_SMALL("ATRAC1 (Adaptive TRansform Acoustic Coding)"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_ATRAC1,
    .priv_data_size = sizeof(AT1Ctx),
    .init           = atrac1_decode_init,
    .close          = atrac1_decode_end,
    .decode         = atrac1_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                      AV_SAMPLE_FMT_NONE },
}

Definition at line 380 of file atrac1.c.