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alac.c File Reference

ALAC (Apple Lossless Audio Codec) decoder. More...

#include <inttypes.h>
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "internal.h"
#include "thread.h"
#include "unary.h"
#include "mathops.h"
#include "alac_data.h"

Go to the source code of this file.

Data Structures

struct  ALACContext




static unsigned int decode_scalar (GetBitContext *gb, int k, int bps)
static int rice_decompress (ALACContext *alac, int32_t *output_buffer, int nb_samples, int bps, int rice_history_mult)
static int sign_only (int v)
static void lpc_prediction (int32_t *error_buffer, int32_t *buffer_out, int nb_samples, int bps, int16_t *lpc_coefs, int lpc_order, int lpc_quant)
static void decorrelate_stereo (int32_t *buffer[2], int nb_samples, int decorr_shift, int decorr_left_weight)
static void append_extra_bits (int32_t *buffer[2], int32_t *extra_bits_buffer[2], int extra_bits, int channels, int nb_samples)
static int decode_element (AVCodecContext *avctx, AVFrame *frame, int ch_index, int channels)
static int alac_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
static av_cold int alac_decode_close (AVCodecContext *avctx)
static int allocate_buffers (ALACContext *alac)
static int alac_set_info (ALACContext *alac)
static av_cold int alac_decode_init (AVCodecContext *avctx)
static int init_thread_copy (AVCodecContext *avctx)


static const AVOption options []
static const AVClass alac_class
AVCodec ff_alac_decoder

Detailed Description

ALAC (Apple Lossless Audio Codec) decoder.

2005 David Hammerton
See Also

Note: This decoder expects a 36-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:

32bit atom size 32bit tag ("alac") 32bit tag version (0) 32bit samples per frame (used when not set explicitly in the frames) 8bit compatible version (0) 8bit sample size 8bit history mult (40) 8bit initial history (10) 8bit rice param limit (14) 8bit channels 16bit maxRun (255) 32bit max coded frame size (0 means unknown) 32bit average bitrate (0 means unknown) 32bit samplerate

Definition in file alac.c.

Macro Definition Documentation


Definition at line 61 of file alac.c.

Referenced by alac_decode_init().

Function Documentation

static unsigned int decode_scalar ( GetBitContext gb,
int  k,
int  bps 

Definition at line 86 of file alac.c.

Referenced by rice_decompress().

static int rice_decompress ( ALACContext alac,
int32_t output_buffer,
int  nb_samples,
int  bps,
int  rice_history_mult 

Definition at line 108 of file alac.c.

Referenced by decode_element().

static int sign_only ( int  v)

Definition at line 165 of file alac.c.

Referenced by lpc_prediction().

static void lpc_prediction ( int32_t error_buffer,
int32_t buffer_out,
int  nb_samples,
int  bps,
int16_t *  lpc_coefs,
int  lpc_order,
int  lpc_quant 

Definition at line 170 of file alac.c.

Referenced by decode_element().

static void decorrelate_stereo ( int32_t buffer[2],
int  nb_samples,
int  decorr_shift,
int  decorr_left_weight 

Definition at line 233 of file alac.c.

Referenced by decode_element().

static void append_extra_bits ( int32_t buffer[2],
int32_t extra_bits_buffer[2],
int  extra_bits,
int  channels,
int  nb_samples 

Definition at line 252 of file alac.c.

Referenced by decode_element().

static int decode_element ( AVCodecContext avctx,
AVFrame frame,
int  ch_index,
int  channels 

Definition at line 262 of file alac.c.

Referenced by alac_decode_frame().

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

Definition at line 458 of file alac.c.

static av_cold int alac_decode_close ( AVCodecContext avctx)

Definition at line 517 of file alac.c.

Referenced by allocate_buffers().

static int allocate_buffers ( ALACContext alac)

Definition at line 532 of file alac.c.

Referenced by alac_decode_init(), and init_thread_copy().

static int alac_set_info ( ALACContext alac)

Definition at line 556 of file alac.c.

Referenced by alac_decode_init().

static av_cold int alac_decode_init ( AVCodecContext avctx)

Definition at line 587 of file alac.c.

static int init_thread_copy ( AVCodecContext avctx)

Definition at line 640 of file alac.c.

Variable Documentation

const AVOption options[]
Initial value:
= {
{ "extra_bits_bug", "Force non-standard decoding process",
0x42, AV_OPT_TYPE_INT, { .i64 = 0 },
{ NULL },
#define NULL
Definition: coverity.c:32
Definition: opt.h:290
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:286

Definition at line 647 of file alac.c.

const AVClass alac_class
Initial value:
= {
.class_name = "alac",
.item_name = av_default_item_name,
.option = options,
Definition: version.h:62
static const AVOption options[]
Definition: alac.c:647

Definition at line 654 of file alac.c.

AVCodec ff_alac_decoder
Initial value:
= {
.name = "alac",
.long_name = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
.priv_data_size = sizeof(ALACContext),
.priv_class = &alac_class
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
static av_cold int alac_decode_close(AVCodecContext *avctx)
Definition: alac.c:517
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:789
static const AVClass alac_class
Definition: alac.c:654
static int alac_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: alac.c:458
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
Define a function with only the non-default version specified.
Definition: internal.h:214
static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
Definition: ccaption_dec.c:522
static av_cold int alac_decode_init(AVCodecContext *avctx)
Definition: alac.c:587
Codec supports frame-level multithreading.
Definition: avcodec.h:866
static int init_thread_copy(AVCodecContext *avctx)
Definition: alac.c:640

Definition at line 661 of file alac.c.