libavcodec/wmavoice.c File Reference

Windows Media Audio Voice compatible decoder. More...

#include <math.h>
#include "avcodec.h"
#include "get_bits.h"
#include "put_bits.h"
#include "wmavoice_data.h"
#include "celp_math.h"
#include "celp_filters.h"
#include "acelp_vectors.h"
#include "acelp_filters.h"
#include "lsp.h"
#include "libavutil/lzo.h"
#include "avfft.h"
#include "fft.h"

Go to the source code of this file.

Data Structures

struct frame_type_desc

Description of frame types. More...

struct WMAVoiceContext

WMA Voice decoding context. More...

Defines

#define MAX_BLOCKS   8

maximum number of blocks per frame

#define MAX_LSPS   16

maximum filter order

#define MAX_LSPS_ALIGN16   16

same as MAX_LSPS; needs to be multiple

#define MAX_FRAMES   3

maximum number of frames per superframe

#define MAX_FRAMESIZE   160

maximum number of samples per frame

#define MAX_SIGNAL_HISTORY   416

maximum excitation signal history

#define MAX_SFRAMESIZE   (MAX_FRAMESIZE * MAX_FRAMES)

maximum number of samples per superframe

#define SFRAME_CACHE_MAXSIZE   256

maximum cache size for frame data that

#define VLC_NBITS   6

number of bits to read per VLC iteration

#define log_range(var, assign)

Enumerations

enum { ACB_TYPE_NONE = 0, ACB_TYPE_ASYMMETRIC = 1, ACB_TYPE_HAMMING = 2 }

Adaptive codebook types. More...

enum { FCB_TYPE_SILENCE = 0, FCB_TYPE_HARDCODED = 1, FCB_TYPE_AW_PULSES = 2, FCB_TYPE_EXC_PULSES = 3 }

Fixed codebook types. More...

Functions

static av_cold int decode_vbmtree (GetBitContext *gb, int8_t vbm_tree[25])

Sets up the variable bit mode (VBM) tree from container extradata.

static av_cold int wmavoice_decode_init (AVCodecContext *ctx)

Set up decoder with parameters from demuxer (extradata etc.

static void adaptive_gain_control (float *out, const float *in, const float *speech_synth, int size, float alpha, float *gain_mem)

Adaptive gain control (as used in postfilter).

static int kalman_smoothen (WMAVoiceContext *s, int pitch, const float *in, float *out, int size)

Kalman smoothing function.

static float tilt_factor (const float *lpcs, int n_lpcs)

Get the tilt factor of a formant filter from its transfer function.

static void calc_input_response (WMAVoiceContext *s, float *lpcs, int fcb_type, float *coeffs, int remainder)

Derive denoise filter coefficients (in real domain) from the LPCs.

static void wiener_denoise (WMAVoiceContext *s, int fcb_type, float *synth_pf, int size, const float *lpcs)

This function applies a Wiener filter on the (noisy) speech signal as a means to denoise it.

static void postfilter (WMAVoiceContext *s, const float *synth, float *samples, int size, const float *lpcs, float *zero_exc_pf, int fcb_type, int pitch)

Averaging projection filter, the postfilter used in WMAVoice.

static void dequant_lsps (double *lsps, int num, const uint16_t *values, const uint16_t *sizes, int n_stages, const uint8_t *table, const double *mul_q, const double *base_q)

Dequantize LSPs.

static void dequant_lsp10i (GetBitContext *gb, double *lsps)

Parse 10 independently-coded LSPs.

static void dequant_lsp10r (GetBitContext *gb, double *i_lsps, const double *old, double *a1, double *a2, int q_mode)

Parse 10 independently-coded LSPs, and then derive the tables to generate LSPs for the other frames from them (residual coding).

static void dequant_lsp16i (GetBitContext *gb, double *lsps)

Parse 16 independently-coded LSPs.

static void dequant_lsp16r (GetBitContext *gb, double *i_lsps, const double *old, double *a1, double *a2, int q_mode)

Parse 16 independently-coded LSPs, and then derive the tables to generate LSPs for the other frames from them (residual coding).

static void aw_parse_coords (WMAVoiceContext *s, GetBitContext *gb, const int *pitch)

Parse the offset of the first pitch-adaptive window pulses, and the distribution of pulses between the two blocks in this frame.

static void aw_pulse_set2 (WMAVoiceContext *s, GetBitContext *gb, int block_idx, AMRFixed *fcb)

Apply second set of pitch-adaptive window pulses.

static void aw_pulse_set1 (WMAVoiceContext *s, GetBitContext *gb, int block_idx, AMRFixed *fcb)

Apply first set of pitch-adaptive window pulses.

static int pRNG (int frame_cntr, int block_num, int block_size)

Generate a random number from frame_cntr and block_idx, which will lief in the range [0, 1000 - block_size] (so it can be used as an index in a table of size 1000 of which you want to read block_size entries).

static void synth_block_hardcoded (WMAVoiceContext *s, GetBitContext *gb, int block_idx, int size, const struct frame_type_desc *frame_desc, float *excitation)

Parse hardcoded signal for a single block.

static void synth_block_fcb_acb (WMAVoiceContext *s, GetBitContext *gb, int block_idx, int size, int block_pitch_sh2, const struct frame_type_desc *frame_desc, float *excitation)

Parse FCB/ACB signal for a single block.

static void synth_block (WMAVoiceContext *s, GetBitContext *gb, int block_idx, int size, int block_pitch_sh2, const double *lsps, const double *prev_lsps, const struct frame_type_desc *frame_desc, float *excitation, float *synth)

Parse data in a single block.

static int synth_frame (AVCodecContext *ctx, GetBitContext *gb, int frame_idx, float *samples, const double *lsps, const double *prev_lsps, float *excitation, float *synth)

Synthesize output samples for a single frame.

static void stabilize_lsps (double *lsps, int num)

Ensure minimum value for first item, maximum value for last value, proper spacing between each value and proper ordering.

static int check_bits_for_superframe (GetBitContext *orig_gb, WMAVoiceContext *s)

Test if there's enough bits to read 1 superframe.

static int synth_superframe (AVCodecContext *ctx, float *samples, int *data_size)

Synthesize output samples for a single superframe.

static int parse_packet_header (WMAVoiceContext *s)

Parse the packet header at the start of each packet (input data to this decoder).

static void copy_bits (PutBitContext *pb, const uint8_t *data, int size, GetBitContext *gb, int nbits)

Copy (unaligned) bits from gb/data/size to pb.

static int wmavoice_decode_packet (AVCodecContext *ctx, void *data, int *data_size, AVPacket *avpkt)

Packet decoding: a packet is anything that the (ASF) demuxer contains, and we expect that the demuxer / application provides it to us as such (else you'll probably get garbage as output).

static av_cold int wmavoice_decode_end (AVCodecContext *ctx)

static av_cold void wmavoice_flush (AVCodecContext *ctx)

Variables

static VLC frame_type_vlc

Frame type VLC coding.

static struct frame_type_desc frame_descs [17]

Description of frame types.

AVCodec wmavoice_decoder

Detailed Description

Windows Media Audio Voice compatible decoder.

Author:: Ronald S. Bultje <rsbultje@gmail.com>

Definition in file wmavoice.c.

Define Documentation

#define log_range	(	var,
		assign		)

Value:

do { \
        float tmp = log10f(assign);  var = tmp; \
        max       = FFMAX(max, tmp); min = FFMIN(min, tmp); \
    } while (0)

Referenced by calc_input_response().

#define MAX_BLOCKS 8

maximum number of blocks per frame

Definition at line 42 of file wmavoice.c.

#define MAX_FRAMES 3

maximum number of frames per superframe

Definition at line 46 of file wmavoice.c.

Referenced by check_bits_for_superframe(), and synth_superframe().

#define MAX_FRAMESIZE 160

maximum number of samples per frame

Definition at line 47 of file wmavoice.c.

#define MAX_LSPS 16

maximum filter order

Definition at line 43 of file wmavoice.c.

Referenced by synth_block(), synth_frame(), synth_superframe(), and wmavoice_flush().

#define MAX_LSPS_ALIGN16 16

same as MAX_LSPS; needs to be multiple

of 16 for ASM input buffer alignment

Definition at line 44 of file wmavoice.c.

Referenced by postfilter(), and wmavoice_flush().

#define MAX_SFRAMESIZE (MAX_FRAMESIZE * MAX_FRAMES)

maximum number of samples per superframe

Definition at line 49 of file wmavoice.c.

Referenced by synth_superframe().

#define MAX_SIGNAL_HISTORY 416

maximum excitation signal history

Definition at line 48 of file wmavoice.c.

Referenced by synth_superframe(), wmavoice_decode_init(), and wmavoice_flush().

#define SFRAME_CACHE_MAXSIZE 256

maximum cache size for frame data that

was split over two packets

Definition at line 51 of file wmavoice.c.

Referenced by wmavoice_decode_packet().

#define VLC_NBITS 6

number of bits to read per VLC iteration

Definition at line 53 of file wmavoice.c.

Referenced by decode_vbmtree().

Enumeration Type Documentation

anonymous enum

Adaptive codebook types.

Enumerator:

ACB_TYPE_NONE

no adaptive codebook (only hardcoded fixed)

ACB_TYPE_ASYMMETRIC

adaptive codebook with per-frame pitch, which we interpolate to get a per-sample pitch.

Signal is generated using an asymmetric sinc window function

Note:: see wmavoice_ipol1_coeffs

ACB_TYPE_HAMMING

Per-block pitch with signal generation using a Hamming sinc window function.

Note:: see wmavoice_ipol2_coeffs

Definition at line 63 of file wmavoice.c.

anonymous enum

Fixed codebook types.

Enumerator:

FCB_TYPE_SILENCE	comfort noise during silence generated from a hardcoded (fixed) codebook with per-frame (low) gain values
FCB_TYPE_HARDCODED	hardcoded (fixed) codebook with per-block gain values
FCB_TYPE_AW_PULSES	Pitch-adaptive window (AW) pulse signals, used in particular for low-bitrate streams.
FCB_TYPE_EXC_PULSES	Innovation (fixed) codebook pulse sets in combinations of either single pulses or pulse pairs.

Definition at line 78 of file wmavoice.c.

Function Documentation

static int check_bits_for_superframe	(	GetBitContext *	orig_gb,
		WMAVoiceContext *	s
	)			`[static]`

Test if there's enough bits to read 1 superframe.

Parameters:

	orig_gb	bit I/O context used for reading. This function does not modify the state of the bitreader; it only uses it to copy the current stream position
	s	WMA Voice decoding context private data

Returns:: -1 if unsupported, 1 on not enough bits or 0 if OK.

Definition at line 1626 of file wmavoice.c.

Referenced by synth_superframe().

static void copy_bits	(	PutBitContext *	pb,
		const uint8_t *	data,
		int	size,
		GetBitContext *	gb,
		int	nbits
	)			`[static]`

Copy (unaligned) bits from gb/data/size to pb.

Parameters:

	pb	target buffer to copy bits into
	data	source buffer to copy bits from
	size	size of the source data, in bytes
	gb	bit I/O context specifying the current position in the source. data. This function might use this to align the bit position to a whole-byte boundary before calling ff_copy_bits() on aligned source data
	nbits	the amount of bits to copy from source to target

Note:: after calling this function, the current position in the input bit I/O context is undefined.

Definition at line 1868 of file wmavoice.c.

static av_cold int decode_vbmtree	(	GetBitContext *	gb,
		int8_t	vbm_tree[25]
	)			`[static]`

Sets up the variable bit mode (VBM) tree from container extradata.

Parameters:

	gb	bit I/O context. The bit context (s->gb) should be loaded with byte 23-46 of the container extradata (i.e. the ones containing the VBM tree).
	vbm_tree	pointer to array to which the decoded VBM tree will be written.

Returns:: 0 on success, <0 on error.

Definition at line 298 of file wmavoice.c.

Referenced by wmavoice_decode_init().

static void dequant_lsps	(	double *	lsps,
		int	num,
		const uint16_t *	values,
		const uint16_t *	sizes,
		int	n_stages,
		const uint8_t *	table,
		const double *	mul_q,
		const double *	base_q
	)			`[static]`

Dequantize LSPs.

Parameters:

	lsps	output pointer to the array that will hold the LSPs
	num	number of LSPs to be dequantized
	values	quantized values, contains n_stages values
	sizes	range (i.e. max value) of each quantized value
	n_stages	number of dequantization runs
	table	dequantization table to be used
	mul_q	LSF multiplier
	base_q	base (lowest) LSF values

Definition at line 804 of file wmavoice.c.

Referenced by dequant_lsp10i(), dequant_lsp10r(), dequant_lsp16i(), and dequant_lsp16r().

static int parse_packet_header ( WMAVoiceContext * s ) [static]

Parse the packet header at the start of each packet (input data to this decoder).

Parameters:

s

WMA Voice decoding context private data

Returns:: 1 if not enough bits were available, or 0 on success.

Definition at line 1833 of file wmavoice.c.

Referenced by gxf_header(), gxf_packet(), gxf_resync_media(), and wmavoice_decode_packet().

static int pRNG	(	int	frame_cntr,
		int	block_num,
		int	block_size
	)			`[static]`

Generate a random number from frame_cntr and block_idx, which will lief in the range [0, 1000 - block_size] (so it can be used as an index in a table of size 1000 of which you want to read block_size entries).

Parameters:

	frame_cntr	current frame number
	block_num	current block index
	block_size	amount of entries we want to read from a table that has 1000 entries

Returns:: a (non-)random number in the [0, 1000 - block_size] range.

Definition at line 1180 of file wmavoice.c.

Referenced by synth_block_hardcoded().

static void stabilize_lsps	(	double *	lsps,
		int	num
	)			`[static]`

Ensure minimum value for first item, maximum value for last value, proper spacing between each value and proper ordering.

Parameters:

	lsps	array of LSPs
	num	size of LSP array

Note:: basically a double version of ff_acelp_reorder_lsf(), might be useful to put in a generic location later on. Parts are also present in ff_set_min_dist_lsf() + ff_sort_nearly_sorted_floats(), which is in float.

Definition at line 1588 of file wmavoice.c.

Referenced by synth_superframe().

static void synth_block	(	WMAVoiceContext *	s,
		GetBitContext *	gb,
		int	block_idx,
		int	size,
		int	block_pitch_sh2,
		const double *	lsps,
		const double *	prev_lsps,
		const struct frame_type_desc *	frame_desc,
		float *	excitation,
		float *	synth
	)			`[static]`

Parse data in a single block.

Note:: we assume enough bits are available, caller should check.

Parameters:

	s	WMA Voice decoding context private data
	gb	bit I/O context
	block_idx	index of the to-be-read block
	size	amount of samples to be read in this block
	block_pitch_sh2	pitch for this block << 2
	lsps	LSPs for (the end of) this frame
	prev_lsps	LSPs for the last frame
	frame_desc	frame type descriptor
	excitation	target memory for the ACB+FCB interpolated signal
	synth	target memory for the speech synthesis filter output

Returns:: 0 on success, <0 on error.

Definition at line 1370 of file wmavoice.c.

Referenced by synth_frame().

static void synth_block_fcb_acb	(	WMAVoiceContext *	s,
		GetBitContext *	gb,
		int	block_idx,
		int	size,
		int	block_pitch_sh2,
		const struct frame_type_desc *	frame_desc,
		float *	excitation
	)			`[static]`

Parse FCB/ACB signal for a single block.

Note:: see synth_block().

Definition at line 1247 of file wmavoice.c.

Referenced by synth_block().

static void synth_block_hardcoded	(	WMAVoiceContext *	s,
		GetBitContext *	gb,
		int	block_idx,
		int	size,
		const struct frame_type_desc *	frame_desc,
		float *	excitation
	)			`[static]`

Parse hardcoded signal for a single block.

Note:: see synth_block().

Definition at line 1216 of file wmavoice.c.

Referenced by synth_block().

static int synth_frame	(	AVCodecContext *	ctx,
		GetBitContext *	gb,
		int	frame_idx,
		float *	samples,
		const double *	lsps,
		const double *	prev_lsps,
		float *	excitation,
		float *	synth
	)			`[static]`

Synthesize output samples for a single frame.

Note:: we assume enough bits are available, caller should check.

Parameters:

	ctx	WMA Voice decoder context
	gb	bit I/O context (s->gb or one for cross-packet superframes)
	frame_idx	Frame number within superframe [0-2]
	samples	pointer to output sample buffer, has space for at least 160 samples
	lsps	LSP array
	prev_lsps	array of previous frame's LSPs
	excitation	target buffer for excitation signal
	synth	target buffer for synthesized speech data

Returns:: 0 on success, <0 on error.

Definition at line 1413 of file wmavoice.c.

Referenced by synth_superframe().

static int synth_superframe	(	AVCodecContext *	ctx,
		float *	samples,
		int *	data_size
	)			`[static]`

Synthesize output samples for a single superframe.

If we have any data cached in s->sframe_cache, that will be used instead of whatever is loaded in s->gb.

WMA Voice superframes contain 3 frames, each containing 160 audio samples, to give a total of 480 samples per frame. See synth_frame() for frame parsing. In addition to 3 frames, superframes can also contain the LSPs (if these are globally specified for all frames (residually); they can also be specified individually per-frame. See the s->has_residual_lsps option), and can specify the number of samples encoded in this superframe (if less than 480), usually used to prevent blanks at track boundaries.

Parameters:

	ctx	WMA Voice decoder context
	samples	pointer to output buffer for voice samples
	data_size	pointer containing the size of samples on input, and the amount of samples filled on output

Returns:: 0 on success, <0 on error or 1 if there was not enough data to fully parse the superframe

Definition at line 1714 of file wmavoice.c.

Referenced by wmavoice_decode_packet().

static av_cold int wmavoice_decode_end ( AVCodecContext * ctx ) [static]

Definition at line 1976 of file wmavoice.c.

static av_cold int wmavoice_decode_init ( AVCodecContext * ctx ) [static]

Set up decoder with parameters from demuxer (extradata etc.

).

Extradata layout:

byte 0-18: WMAPro-in-WMAVoice extradata (see wmaprodec.c),
byte 19-22: flags field (annoyingly in LE; see below for known values),
byte 23-46: variable bitmode tree (really just 17 * 3 bits, rest is 0).

Definition at line 333 of file wmavoice.c.

static int wmavoice_decode_packet	(	AVCodecContext *	ctx,
		void *	data,
		int *	data_size,
		AVPacket *	avpkt
	)			`[static]`

Packet decoding: a packet is anything that the (ASF) demuxer contains, and we expect that the demuxer / application provides it to us as such (else you'll probably get garbage as output).

Every packet has a size of ctx->block_align bytes, starts with a packet header (see parse_packet_header()), and then a series of superframes. Superframe boundaries may exceed packets, i.e. superframes can split data over multiple (two) packets.

For more information about frames, see synth_superframe().

Definition at line 1895 of file wmavoice.c.

static av_cold void wmavoice_flush ( AVCodecContext * ctx ) [static]

Definition at line 1990 of file wmavoice.c.

Variable Documentation

struct frame_type_desc frame_descs[17] [static]

Description of frame types.

Referenced by check_bits_for_superframe(), and synth_frame().

VLC frame_type_vlc [static]

Frame type VLC coding.

Definition at line 58 of file wmavoice.c.

AVCodec wmavoice_decoder

Initial value:

 {
    "wmavoice",
    AVMEDIA_TYPE_AUDIO,
    CODEC_ID_WMAVOICE,
    sizeof(WMAVoiceContext),
    wmavoice_decode_init,
    NULL,
    wmavoice_decode_end,
    wmavoice_decode_packet,
    CODEC_CAP_SUBFRAMES,
    .flush     = wmavoice_flush,
    .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio Voice"),
}

Definition at line 2018 of file wmavoice.c.


Data Structures
struct	frame_type_desc
	Description of frame types. More...
struct	WMAVoiceContext
	WMA Voice decoding context. More...
Defines
#define	MAX_BLOCKS 8
	maximum number of blocks per frame
#define	MAX_LSPS 16
	maximum filter order
#define	MAX_LSPS_ALIGN16 16
	same as MAX_LSPS; needs to be multiple
#define	MAX_FRAMES 3
	maximum number of frames per superframe
#define	MAX_FRAMESIZE 160
	maximum number of samples per frame
#define	MAX_SIGNAL_HISTORY 416
	maximum excitation signal history
#define	MAX_SFRAMESIZE (MAX_FRAMESIZE * MAX_FRAMES)
	maximum number of samples per superframe
#define	SFRAME_CACHE_MAXSIZE 256
	maximum cache size for frame data that
#define	VLC_NBITS 6
	number of bits to read per VLC iteration
#define	log_range(var, assign)
Enumerations
enum	{ ACB_TYPE_NONE = 0, ACB_TYPE_ASYMMETRIC = 1, ACB_TYPE_HAMMING = 2 }
	Adaptive codebook types. More...
enum	{ FCB_TYPE_SILENCE = 0, FCB_TYPE_HARDCODED = 1, FCB_TYPE_AW_PULSES = 2, FCB_TYPE_EXC_PULSES = 3 }
	Fixed codebook types. More...
Functions
static av_cold int	decode_vbmtree (GetBitContext *gb, int8_t vbm_tree[25])
	Sets up the variable bit mode (VBM) tree from container extradata.
static av_cold int	wmavoice_decode_init (AVCodecContext *ctx)
	Set up decoder with parameters from demuxer (extradata etc.
static void	adaptive_gain_control (float out, const float in, const float speech_synth, int size, float alpha, float gain_mem)
	Adaptive gain control (as used in postfilter).
static int	kalman_smoothen (WMAVoiceContext s, int pitch, const float in, float *out, int size)
	Kalman smoothing function.
static float	tilt_factor (const float *lpcs, int n_lpcs)
	Get the tilt factor of a formant filter from its transfer function.
static void	calc_input_response (WMAVoiceContext s, float lpcs, int fcb_type, float *coeffs, int remainder)
	Derive denoise filter coefficients (in real domain) from the LPCs.
static void	wiener_denoise (WMAVoiceContext s, int fcb_type, float synth_pf, int size, const float *lpcs)
	This function applies a Wiener filter on the (noisy) speech signal as a means to denoise it.
static void	postfilter (WMAVoiceContext s, const float synth, float samples, int size, const float lpcs, float *zero_exc_pf, int fcb_type, int pitch)
	Averaging projection filter, the postfilter used in WMAVoice.
static void	dequant_lsps (double lsps, int num, const uint16_t values, const uint16_t sizes, int n_stages, const uint8_t table, const double mul_q, const double base_q)
	Dequantize LSPs.
static void	dequant_lsp10i (GetBitContext gb, double lsps)
	Parse 10 independently-coded LSPs.
static void	dequant_lsp10r (GetBitContext gb, double i_lsps, const double old, double a1, double *a2, int q_mode)
	Parse 10 independently-coded LSPs, and then derive the tables to generate LSPs for the other frames from them (residual coding).
static void	dequant_lsp16i (GetBitContext gb, double lsps)
	Parse 16 independently-coded LSPs.
static void	dequant_lsp16r (GetBitContext gb, double i_lsps, const double old, double a1, double *a2, int q_mode)
	Parse 16 independently-coded LSPs, and then derive the tables to generate LSPs for the other frames from them (residual coding).
static void	aw_parse_coords (WMAVoiceContext s, GetBitContext gb, const int *pitch)
	Parse the offset of the first pitch-adaptive window pulses, and the distribution of pulses between the two blocks in this frame.
static void	aw_pulse_set2 (WMAVoiceContext s, GetBitContext gb, int block_idx, AMRFixed *fcb)
	Apply second set of pitch-adaptive window pulses.
static void	aw_pulse_set1 (WMAVoiceContext s, GetBitContext gb, int block_idx, AMRFixed *fcb)
	Apply first set of pitch-adaptive window pulses.
static int	pRNG (int frame_cntr, int block_num, int block_size)
	Generate a random number from frame_cntr and block_idx, which will lief in the range [0, 1000 - block_size] (so it can be used as an index in a table of size 1000 of which you want to read block_size entries).
static void	synth_block_hardcoded (WMAVoiceContext s, GetBitContext gb, int block_idx, int size, const struct frame_type_desc frame_desc, float excitation)
	Parse hardcoded signal for a single block.
static void	synth_block_fcb_acb (WMAVoiceContext s, GetBitContext gb, int block_idx, int size, int block_pitch_sh2, const struct frame_type_desc frame_desc, float excitation)
	Parse FCB/ACB signal for a single block.
static void	synth_block (WMAVoiceContext s, GetBitContext gb, int block_idx, int size, int block_pitch_sh2, const double lsps, const double prev_lsps, const struct frame_type_desc frame_desc, float excitation, float *synth)
	Parse data in a single block.
static int	synth_frame (AVCodecContext ctx, GetBitContext gb, int frame_idx, float samples, const double lsps, const double prev_lsps, float excitation, float *synth)
	Synthesize output samples for a single frame.
static void	stabilize_lsps (double *lsps, int num)
	Ensure minimum value for first item, maximum value for last value, proper spacing between each value and proper ordering.
static int	check_bits_for_superframe (GetBitContext orig_gb, WMAVoiceContext s)
	Test if there's enough bits to read 1 superframe.
static int	synth_superframe (AVCodecContext ctx, float samples, int *data_size)
	Synthesize output samples for a single superframe.
static int	parse_packet_header (WMAVoiceContext *s)
	Parse the packet header at the start of each packet (input data to this decoder).
static void	copy_bits (PutBitContext pb, const uint8_t data, int size, GetBitContext *gb, int nbits)
	Copy (unaligned) bits from gb/data/size to pb.
static int	wmavoice_decode_packet (AVCodecContext ctx, void data, int data_size, AVPacket avpkt)
	Packet decoding: a packet is anything that the (ASF) demuxer contains, and we expect that the demuxer / application provides it to us as such (else you'll probably get garbage as output).
static av_cold int	wmavoice_decode_end (AVCodecContext *ctx)
static av_cold void	wmavoice_flush (AVCodecContext *ctx)
Variables
static VLC	frame_type_vlc
	Frame type VLC coding.
static struct frame_type_desc	frame_descs [17]
	Description of frame types.
AVCodec	wmavoice_decoder