wmalosslessdec.c File Reference

#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "internal.h"
#include "get_bits.h"
#include "put_bits.h"
#include "wma.h"
#include "wma_common.h"

Include dependency graph for wmalosslessdec.c:

Go to the source code of this file.

Data Structures
struct	WmallChannelCtx
	frame-specific decoder context for a single channel More...
struct	WmallDecodeCtx
	main decoder context More...

Macros
#define	WMALL_MAX_CHANNELS   8
	current decoder limitations More...
#define	MAX_SUBFRAMES   32
	max number of subframes per channel More...
#define	MAX_BANDS   29
	max number of scale factor bands More...
#define	MAX_FRAMESIZE   32768
	maximum compressed frame size More...
#define	MAX_ORDER   256
#define	WMALL_BLOCK_MIN_BITS   6
	log2 of min block size More...
#define	WMALL_BLOCK_MAX_BITS   14
	log2 of max block size More...
#define	WMALL_BLOCK_MAX_SIZE   (1 << WMALL_BLOCK_MAX_BITS)
	maximum block size More...
#define	WMALL_BLOCK_SIZES   (WMALL_BLOCK_MAX_BITS - WMALL_BLOCK_MIN_BITS + 1)
	possible block sizes More...

Typedefs
typedef struct WmallDecodeCtx	WmallDecodeCtx
	main decoder context More...

Functions
static av_cold int	decode_init (AVCodecContext *avctx)
static int	decode_subframe_length (WmallDecodeCtx *s, int offset)
	Decode the subframe length. More...
static int	decode_tilehdr (WmallDecodeCtx *s)
	Decode how the data in the frame is split into subframes. More...
static void	decode_ac_filter (WmallDecodeCtx *s)
static void	decode_mclms (WmallDecodeCtx *s)
static int	decode_cdlms (WmallDecodeCtx *s)
static int	decode_channel_residues (WmallDecodeCtx *s, int ch, int tile_size)
static void	decode_lpc (WmallDecodeCtx *s)
static void	clear_codec_buffers (WmallDecodeCtx *s)
static void	reset_codec (WmallDecodeCtx *s)
	Reset filter parameters and transient area at new seekable tile. More...
static void	mclms_update (WmallDecodeCtx *s, int icoef, int *pred)
static void	mclms_predict (WmallDecodeCtx *s, int icoef, int *pred)
static void	revert_mclms (WmallDecodeCtx *s, int tile_size)
static int	lms_predict (WmallDecodeCtx *s, int ich, int ilms)
static void	lms_update (WmallDecodeCtx *s, int ich, int ilms, int input, int residue)
static void	use_high_update_speed (WmallDecodeCtx *s, int ich)
static void	use_normal_update_speed (WmallDecodeCtx *s, int ich)
static void	revert_cdlms (WmallDecodeCtx *s, int ch, int coef_begin, int coef_end)
static void	revert_inter_ch_decorr (WmallDecodeCtx *s, int tile_size)
static void	revert_acfilter (WmallDecodeCtx *s, int tile_size)
static int	decode_subframe (WmallDecodeCtx *s)
static int	decode_frame (WmallDecodeCtx *s)
	Decode one WMA frame. More...
static int	remaining_bits (WmallDecodeCtx *s, GetBitContext *gb)
	Calculate remaining input buffer length. More...
static void	save_bits (WmallDecodeCtx *s, GetBitContext *gb, int len, int append)
	Fill the bit reservoir with a (partial) frame. More...
static int	decode_packet (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
static void	flush (AVCodecContext *avctx)

Variables
AVCodec	ff_wmalossless_decoder

Macro Definition Documentation

#define MAX_BANDS   29

max number of scale factor bands

Definition at line 38 of file wmalosslessdec.c.

#define MAX_FRAMESIZE   32768

maximum compressed frame size

Definition at line 39 of file wmalosslessdec.c.

Referenced by decode_init(), decode_packet(), flush(), and save_bits().

#define MAX_ORDER   256

Definition at line 40 of file wmalosslessdec.c.

Referenced by decode_cdlms().

#define MAX_SUBFRAMES   32

max number of subframes per channel

Definition at line 37 of file wmalosslessdec.c.

Referenced by decode_init(), and decode_tilehdr().

#define WMALL_BLOCK_MAX_BITS   14

log2 of max block size

Definition at line 43 of file wmalosslessdec.c.

#define WMALL_BLOCK_MAX_SIZE   (1 << WMALL_BLOCK_MAX_BITS)

maximum block size

Definition at line 44 of file wmalosslessdec.c.

Referenced by decode_init().

#define WMALL_BLOCK_MIN_BITS   6

log2 of min block size

Definition at line 42 of file wmalosslessdec.c.

#define WMALL_BLOCK_SIZES   (WMALL_BLOCK_MAX_BITS - WMALL_BLOCK_MIN_BITS + 1)

possible block sizes

Definition at line 45 of file wmalosslessdec.c.

#define WMALL_MAX_CHANNELS   8

current decoder limitations

max number of handled channels

Definition at line 36 of file wmalosslessdec.c.

Referenced by decode_init(), decode_tilehdr(), and revert_mclms().

Typedef Documentation

typedef struct WmallDecodeCtx WmallDecodeCtx

main decoder context

Function Documentation

static void clear_codec_buffers ( WmallDecodeCtx *  s )

static

Definition at line 554 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void decode_ac_filter ( WmallDecodeCtx *  s )

static

Definition at line 403 of file wmalosslessdec.c.

Referenced by decode_subframe().

static int decode_cdlms ( WmallDecodeCtx *  s )

static

Definition at line 437 of file wmalosslessdec.c.

Referenced by decode_subframe().

static int decode_channel_residues ( WmallDecodeCtx *  s, int  ch, int  tile_size  )

static

Definition at line 483 of file wmalosslessdec.c.

Referenced by decode_subframe().

static int decode_frame ( WmallDecodeCtx *  s )

static

Decode one WMA frame.

Parameters

s	codec context

Returns

0 if the trailer bit indicates that this is the last frame, 1 if there are additional frames

Definition at line 1013 of file wmalosslessdec.c.

Referenced by decode_packet().

static av_cold int decode_init ( AVCodecContext *  avctx )

static

Definition at line 174 of file wmalosslessdec.c.

static void decode_lpc ( WmallDecodeCtx *  s )

static

Definition at line 542 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void decode_mclms ( WmallDecodeCtx *  s )

static

Definition at line 414 of file wmalosslessdec.c.

Referenced by decode_subframe().

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

static

Definition at line 1164 of file wmalosslessdec.c.

static int decode_subframe ( WmallDecodeCtx *  s )

static

Definition at line 839 of file wmalosslessdec.c.

Referenced by decode_frame().

static int decode_subframe_length ( WmallDecodeCtx *  s, int  offset  )

static

Decode the subframe length.

Parameters

s	context
offset	sample offset in the frame

Returns

decoded subframe length on success, < 0 in case of an error

Definition at line 276 of file wmalosslessdec.c.

Referenced by decode_tilehdr().

static int decode_tilehdr ( WmallDecodeCtx *  s )

static

Decode how the data in the frame is split into subframes.

Every WMA frame contains the encoded data for a fixed number of samples per channel. The data for every channel might be split into several subframes. This function will reconstruct the list of subframes for every channel.

If the subframes are not evenly split, the algorithm estimates the channels with the lowest number of total samples. Afterwards, for each of these channels a bit is read from the bitstream that indicates if the channel contains a subframe with the next subframe size that is going to be read from the bitstream or not. If a channel contains such a subframe, the subframe size gets added to the channel's subframe list. The algorithm repeats these steps until the frame is properly divided between the individual channels.

Parameters

s

context

Returns

0 on success, < 0 in case of an error

Definition at line 318 of file wmalosslessdec.c.

Referenced by decode_frame().

static void flush ( AVCodecContext *  avctx )

static

Definition at line 1274 of file wmalosslessdec.c.

static int lms_predict ( WmallDecodeCtx *  s, int  ich, int  ilms  )

static

Definition at line 687 of file wmalosslessdec.c.

Referenced by revert_cdlms().

static void lms_update ( WmallDecodeCtx *  s, int  ich, int  ilms, int  input, int  residue  )

static

Definition at line 699 of file wmalosslessdec.c.

Referenced by revert_cdlms().

static void mclms_predict ( WmallDecodeCtx *  s, int  icoef, int *  pred  )

static

Definition at line 656 of file wmalosslessdec.c.

Referenced by revert_mclms().

static void mclms_update ( WmallDecodeCtx *  s, int  icoef, int *  pred  )

static

Definition at line 598 of file wmalosslessdec.c.

Referenced by revert_mclms().

static int remaining_bits ( WmallDecodeCtx *  s, GetBitContext *  gb  )

static

Calculate remaining input buffer length.

Parameters

s	codec context
gb	bitstream reader context

Returns

remaining size in bits

Definition at line 1108 of file wmalosslessdec.c.

Referenced by decode_packet().

static void reset_codec ( WmallDecodeCtx *  s )

static

Reset filter parameters and transient area at new seekable tile.

Definition at line 583 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void revert_acfilter ( WmallDecodeCtx *  s, int  tile_size  )

static

Definition at line 807 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void revert_cdlms ( WmallDecodeCtx *  s, int  ch, int  coef_begin, int  coef_end  )

static

Definition at line 776 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void revert_inter_ch_decorr ( WmallDecodeCtx *  s, int  tile_size  )

static

Definition at line 794 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void revert_mclms ( WmallDecodeCtx *  s, int  tile_size  )

static

Definition at line 678 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void save_bits ( WmallDecodeCtx *  s, GetBitContext *  gb, int  len, int  append  )

static

Fill the bit reservoir with a (partial) frame.

Parameters

s	codec context
gb	bitstream reader context
len	length of the partial frame
append	decides whether to reset the buffer or not

Definition at line 1120 of file wmalosslessdec.c.

Referenced by decode_packet().

static void use_high_update_speed ( WmallDecodeCtx *  s, int  ich  )

static

Definition at line 741 of file wmalosslessdec.c.

Referenced by decode_subframe().

static void use_normal_update_speed ( WmallDecodeCtx *  s, int  ich  )

static

Definition at line 759 of file wmalosslessdec.c.

Referenced by decode_subframe().

Variable Documentation

AVCodec ff_wmalossless_decoder

Initial value:

= {
    .name           = "wmalossless",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_WMALOSSLESS,
    .priv_data_size = sizeof(WmallDecodeCtx),
    .init           = decode_init,
    .decode         = decode_packet,
    .flush          = flush,
    .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1 | CODEC_CAP_DELAY,
    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Audio Lossless"),
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
                                                      AV_SAMPLE_FMT_S32P,
                                                      AV_SAMPLE_FMT_NONE },
}

Definition at line 1287 of file wmalosslessdec.c.