libavcodec/atrac3.c File Reference

Atrac 3 compatible decoder. More...

#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include "avcodec.h"
#include "get_bits.h"
#include "dsputil.h"
#include "bytestream.h"
#include "fft.h"
#include "fmtconvert.h"
#include "atrac.h"
#include "atrac3data.h"

Go to the source code of this file.

Data Structures

struct  gain_info
struct  gain_block
struct  tonal_component
struct  channel_unit
struct  ATRAC3Context

Defines

#define JOINT_STEREO   0x12
#define STEREO   0x2
#define SAMPLES_PER_FRAME   1024
#define MDCT_SIZE   512
#define INTERPOLATE(old, new, nsample)   ((old) + (nsample)*0.125*((new)-(old)))

Functions

static void IMLT (ATRAC3Context *q, float *pInput, float *pOutput, int odd_band)
 Regular 512 points IMDCT without overlapping, with the exception of the swapping of odd bands caused by the reverse spectra of the QMF.
static int decode_bytes (const uint8_t *inbuffer, uint8_t *out, int bytes)
 Atrac 3 indata descrambling, only used for data coming from the rm container.
static av_cold int init_atrac3_transforms (ATRAC3Context *q, int is_float)
static av_cold int atrac3_decode_close (AVCodecContext *avctx)
 Atrac3 uninit, free all allocated memory.
static void readQuantSpectralCoeffs (GetBitContext *gb, int selector, int codingFlag, int *mantissas, int numCodes)
 / * Mantissa decoding
static int decodeSpectrum (GetBitContext *gb, float *pOut)
 Restore the quantized band spectrum coefficients.
static int decodeTonalComponents (GetBitContext *gb, tonal_component *pComponent, int numBands)
 Restore the quantized tonal components.
static int decodeGainControl (GetBitContext *gb, gain_block *pGb, int numBands)
 Decode gain parameters for the coded bands.
static void gainCompensateAndOverlap (float *pIn, float *pPrev, float *pOut, gain_info *pGain1, gain_info *pGain2)
 Apply gain parameters and perform the MDCT overlapping part.
static int addTonalComponents (float *pSpectrum, int numComponents, tonal_component *pComponent)
 Combine the tonal band spectrum and regular band spectrum Return position of the last tonal coefficient.
static void reverseMatrixing (float *su1, float *su2, int *pPrevCode, int *pCurrCode)
static void getChannelWeights (int indx, int flag, float ch[2])
static void channelWeighting (float *su1, float *su2, int *p3)
static int decodeChannelSoundUnit (ATRAC3Context *q, GetBitContext *gb, channel_unit *pSnd, float *pOut, int channelNum, int codingMode)
 Decode a Sound Unit.
static int decodeFrame (ATRAC3Context *q, const uint8_t *databuf, float **out_samples)
 Frame handling.
static int atrac3_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
 Atrac frame decoding.
static av_cold int atrac3_decode_init (AVCodecContext *avctx)
 Atrac3 initialization.

Variables

static float mdct_window [MDCT_SIZE]
static VLC spectral_coeff_tab [7]
static float gain_tab1 [16]
static float gain_tab2 [31]
static DSPContext dsp
AVCodec ff_atrac3_decoder


Detailed Description

Atrac 3 compatible decoder.

This decoder handles Sony's ATRAC3 data.

Container formats used to store atrac 3 data: RealMedia (.rm), RIFF WAV (.wav, .at3), Sony OpenMG (.oma, .aa3).

To use this decoder, a calling application must supply the extradata bytes provided in the containers above.

Definition in file atrac3.c.


Define Documentation

#define INTERPOLATE ( old,
new,
nsample   )     ((old) + (nsample)*0.125*((new)-(old)))

Definition at line 553 of file atrac3.c.

Referenced by channelWeighting(), reverseMatrixing(), and Super2xSaI_ex().

#define JOINT_STEREO   0x12

#define MDCT_SIZE   512

Definition at line 53 of file atrac3.c.

Referenced by IMLT().

#define SAMPLES_PER_FRAME   1024

#define STEREO   0x2

Definition at line 50 of file atrac3.c.

Referenced by atrac3_decode_init(), and cook_decode_init().


Function Documentation

static int addTonalComponents ( float *  pSpectrum,
int  numComponents,
tonal_component pComponent 
) [static]

Combine the tonal band spectrum and regular band spectrum Return position of the last tonal coefficient.

Parameters:
pSpectrum output spectrum buffer
numComponents amount of tonal components
pComponent tonal components for this band

Definition at line 535 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static av_cold int atrac3_decode_close ( AVCodecContext avctx  )  [static]

Atrac3 uninit, free all allocated memory.

Definition at line 223 of file atrac3.c.

Referenced by atrac3_decode_init().

static int atrac3_decode_frame ( AVCodecContext avctx,
void *  data,
int *  got_frame_ptr,
AVPacket avpkt 
) [static]

Atrac frame decoding.

Parameters:
avctx pointer to the AVCodecContext

Definition at line 832 of file atrac3.c.

static av_cold int atrac3_decode_init ( AVCodecContext avctx  )  [static]

Atrac3 initialization.

Parameters:
avctx pointer to the AVCodecContext

Definition at line 900 of file atrac3.c.

static void channelWeighting ( float *  su1,
float *  su2,
int *  p3 
) [static]

Definition at line 630 of file atrac3.c.

Referenced by decodeFrame().

static int decode_bytes ( const uint8_t *  inbuffer,
uint8_t *  out,
int  bytes 
) [static]

Atrac 3 indata descrambling, only used for data coming from the rm container.

Parameters:
inbuffer pointer to 8 bit array of indata
out pointer to 8 bit array of outdata
bytes amount of bytes

Definition at line 180 of file atrac3.c.

Referenced by atrac3_decode_frame(), and decode_bytes_and_gain().

static int decodeChannelSoundUnit ( ATRAC3Context q,
GetBitContext gb,
channel_unit pSnd,
float *  pOut,
int  channelNum,
int  codingMode 
) [static]

Decode a Sound Unit.

Parameters:
gb the GetBit context
pSnd the channel unit to be used
pOut the decoded samples before IQMF in float representation
channelNum channel number
codingMode the coding mode (JOINT_STEREO or regular stereo/mono)

Definition at line 667 of file atrac3.c.

Referenced by decodeFrame().

static int decodeFrame ( ATRAC3Context q,
const uint8_t *  databuf,
float **  out_samples 
) [static]

Frame handling.

Parameters:
q Atrac3 private context
databuf the input data

Definition at line 732 of file atrac3.c.

Referenced by atrac3_decode_frame().

static int decodeGainControl ( GetBitContext gb,
gain_block pGb,
int  numBands 
) [static]

Decode gain parameters for the coded bands.

Parameters:
gb the GetBit context
pGb the gainblock for the current band
numBands amount of coded bands

Definition at line 439 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static int decodeSpectrum ( GetBitContext gb,
float *  pOut 
) [static]

Restore the quantized band spectrum coefficients.

Parameters:
gb the GetBit context
pOut decoded band spectrum
Returns:
outSubbands subband counter, fix for broken specification/files

Definition at line 304 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static int decodeTonalComponents ( GetBitContext gb,
tonal_component pComponent,
int  numBands 
) [static]

Restore the quantized tonal components.

Parameters:
gb the GetBit context
pComponent tone component
numBands amount of coded bands

Definition at line 362 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static void gainCompensateAndOverlap ( float *  pIn,
float *  pPrev,
float *  pOut,
gain_info pGain1,
gain_info pGain2 
) [static]

Apply gain parameters and perform the MDCT overlapping part.

Parameters:
pIn input float buffer
pPrev previous float buffer to perform overlap against
pOut output float buffer
pGain1 current band gain info
pGain2 next band gain info

Definition at line 478 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static void getChannelWeights ( int  indx,
int  flag,
float  ch[2] 
) [static]

Definition at line 617 of file atrac3.c.

Referenced by channelWeighting().

static void IMLT ( ATRAC3Context q,
float *  pInput,
float *  pOutput,
int  odd_band 
) [static]

Regular 512 points IMDCT without overlapping, with the exception of the swapping of odd bands caused by the reverse spectra of the QMF.

Parameters:
pInput float input
pOutput float output
odd_band 1 if the band is an odd band

Reverse the odd bands before IMDCT, this is an effect of the QMF transform or it gives better compression to do it this way. FIXME: It should be possible to handle this in imdct_calc for that to happen a modification of the prerotation step of all SIMD code and C code is needed. Or fix the functions before so they generate a pre reversed spectrum.

Definition at line 146 of file atrac3.c.

Referenced by decodeChannelSoundUnit().

static av_cold int init_atrac3_transforms ( ATRAC3Context q,
int  is_float 
) [static]

Definition at line 200 of file atrac3.c.

Referenced by atrac3_decode_init().

static void readQuantSpectralCoeffs ( GetBitContext gb,
int  selector,
int  codingFlag,
int *  mantissas,
int  numCodes 
) [static]

/ * Mantissa decoding

Parameters:
gb the GetBit context
selector what table is the output values coded with
codingFlag constant length coding or variable length coding
mantissas mantissa output table
numCodes amount of values to get

Definition at line 246 of file atrac3.c.

Referenced by decodeSpectrum(), and decodeTonalComponents().

static void reverseMatrixing ( float *  su1,
float *  su2,
int *  pPrevCode,
int *  pCurrCode 
) [static]

Definition at line 555 of file atrac3.c.

Referenced by decodeFrame().


Variable Documentation

DSPContext dsp [static]

Initial value:

{
    .name = "atrac3",
    .type = AVMEDIA_TYPE_AUDIO,
    .id = CODEC_ID_ATRAC3,
    .priv_data_size = sizeof(ATRAC3Context),
    .init = atrac3_decode_init,
    .close = atrac3_decode_close,
    .decode = atrac3_decode_frame,
    .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("Atrac 3 (Adaptive TRansform Acoustic Coding 3)"),
}

Definition at line 1067 of file atrac3.c.

float gain_tab1[16] [static]

Definition at line 132 of file atrac3.c.

Referenced by atrac3_decode_init(), and gainCompensateAndOverlap().

float gain_tab2[31] [static]

Definition at line 133 of file atrac3.c.

Referenced by atrac3_decode_init(), and gainCompensateAndOverlap().

float mdct_window[MDCT_SIZE] [static]

Definition at line 130 of file atrac3.c.

Referenced by IMLT(), and init_atrac3_transforms().

VLC spectral_coeff_tab[7] [static]

Definition at line 131 of file atrac3.c.


Generated on Fri Oct 26 02:43:46 2012 for FFmpeg by  doxygen 1.5.8