hvirtual/quicktime/ffmpeg/libavcodec/mpegaudio.c File Reference

#include "avcodec.h"
#include "bitstream.h"
#include "mpegaudio.h"
#include "mpegaudiotab.h"

Include dependency graph for mpegaudio.c:

Go to the source code of this file.

Data Structures
struct	MpegAudioContext
Defines
#define	FRAC_BITS   15
#define	WFRAC_BITS   14
#define	MUL(a, b)   (((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS)
#define	FIX(a)   ((int)((a) * (1 << FRAC_BITS)))
#define	SAMPLES_BUF_SIZE   4096
#define	P   15
#define	WSHIFT   (WFRAC_BITS + 15 - FRAC_BITS)
#define	SB_NOTALLOCATED   0
#define	SB_ALLOCATED   1
#define	SB_NOMORE   2
Functions
static int	MPA_encode_init (AVCodecContext *avctx)
static void	idct32 (int *out, int *tab)
static void	filter (MpegAudioContext *s, int ch, short *samples, int incr)
static void	compute_scale_factors (unsigned char scale_code[SBLIMIT], unsigned char scale_factors[SBLIMIT][3], int sb_samples[3][12][SBLIMIT], int sblimit)
static void	psycho_acoustic_model (MpegAudioContext *s, short smr[SBLIMIT])
static void	compute_bit_allocation (MpegAudioContext *s, short smr1[MPA_MAX_CHANNELS][SBLIMIT], unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT], int *padding)
static void	encode_frame (MpegAudioContext *s, unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT], int padding)
static int	MPA_encode_frame (AVCodecContext *avctx, unsigned char *frame, int buf_size, void *data)
static int	MPA_encode_close (AVCodecContext *avctx)

---

Detailed Description

The simplest mpeg audio layer 2 encoder.

Definition in file mpegaudio.c.

---

Define Documentation

#define FIX

(

a

)

((int)((a) * (1 << FRAC_BITS)))

Definition at line 34 of file mpegaudio.c.

#define FRAC_BITS   15

Definition at line 31 of file mpegaudio.c.

Referenced by add_yblock(), add_yblock_buffered(), decode_frame(), decode_init(), encode_frame(), predict_slice(), and predict_slice_buffered().

#define MUL	(	a,
		b		)	(((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS)

Definition at line 33 of file mpegaudio.c.

#define P   15

#define SAMPLES_BUF_SIZE   4096

Definition at line 36 of file mpegaudio.c.

Referenced by filter().

#define SB_ALLOCATED   1

Definition at line 497 of file mpegaudio.c.

Referenced by compute_bit_allocation().

#define SB_NOMORE   2

Definition at line 498 of file mpegaudio.c.

Referenced by compute_bit_allocation().

#define SB_NOTALLOCATED   0

Definition at line 496 of file mpegaudio.c.

Referenced by compute_bit_allocation().

#define WFRAC_BITS   14

Definition at line 32 of file mpegaudio.c.

Referenced by ff_mpa_synth_init(), and MPA_encode_init().

#define WSHIFT   (WFRAC_BITS + 15 - FRAC_BITS)

Definition at line 308 of file mpegaudio.c.

Referenced by filter().

---

Function Documentation

static void compute_bit_allocation	(	MpegAudioContext *	s,
		short	smr1[MPA_MAX_CHANNELS][SBLIMIT],
		unsigned char	bit_alloc[MPA_MAX_CHANNELS][SBLIMIT],
		int *	padding
	)			[static]

Definition at line 503 of file mpegaudio.c.

References MpegAudioContext::alloc_table, b, bit_alloc(), MpegAudioContext::do_padding, MpegAudioContext::frame_frac, MpegAudioContext::frame_frac_incr, MpegAudioContext::frame_size, memcpy, MPA_MAX_CHANNELS, MpegAudioContext::nb_channels, nb_scale_factors, quant_snr, SB_ALLOCATED, SB_NOMORE, SB_NOTALLOCATED, MpegAudioContext::sblimit, MpegAudioContext::scale_code, and total_quant_bits.

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static void compute_scale_factors	(	unsigned char	scale_code[SBLIMIT],
		unsigned char	scale_factors[SBLIMIT][3],
		int	sb_samples[3][12][SBLIMIT],
		int	sblimit
	)			[static]

Definition at line 367 of file mpegaudio.c.

References scale_diff_table, and scale_factor_table.

Referenced by MPA_encode_frame().

static void encode_frame	(	MpegAudioContext *	s,
		unsigned char	bit_alloc[MPA_MAX_CHANNELS][SBLIMIT],
		int	padding
	)			[static]

Definition at line 608 of file mpegaudio.c.

References a, MpegAudioContext::alloc_table, b, bit_alloc(), MpegAudioContext::bitrate_index, bits, MpegAudioContext::do_padding, e, flush_put_bits(), MpegAudioContext::freq_index, MpegAudioContext::lsf, MPA_MONO, MPA_STEREO, mult(), MpegAudioContext::nb_channels, P, MpegAudioContext::pb, put_bits(), quant_bits, quant_steps, MpegAudioContext::sb_samples, MpegAudioContext::sblimit, MpegAudioContext::scale_code, scale_factor_mult, scale_factor_shift, MpegAudioContext::scale_factors, shift(), and steps.

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static void filter	(	MpegAudioContext *	s,
		int	ch,
		short *	samples,
		int	incr
	)			[static]

Definition at line 310 of file mpegaudio.c.

References filter_bank, idct32(), offset, MpegAudioContext::samples_buf, SAMPLES_BUF_SIZE, MpegAudioContext::samples_offset, MpegAudioContext::sb_samples, and WSHIFT.

Referenced by av_resample(), create_ana_filter(), h_resample_fast(), MPA_encode_frame(), and xa_decode().

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static void idct32	(	int *	out,
		int *	tab
	)			[static]

Definition at line 189 of file mpegaudio.c.

References bitinv32, costab32, FIX, MUL, SQRT2, t, and t1.

Referenced by filter().

static int MPA_encode_close

(

AVCodecContext *

avctx

)

[static]

Definition at line 782 of file mpegaudio.c.

References av_freep(), and AVCodecContext::coded_frame.

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static int MPA_encode_frame	(	AVCodecContext *	avctx,
		unsigned char *	frame,
		int	buf_size,
		void *	data
	)			[static]

Definition at line 752 of file mpegaudio.c.

References bit_alloc(), PutBitContext::buf, compute_bit_allocation(), compute_scale_factors(), encode_frame(), filter(), init_put_bits(), MPA_FRAME_SIZE, MPA_MAX_CHANNELS, MPA_MAX_CODED_FRAME_SIZE, MpegAudioContext::nb_channels, MpegAudioContext::nb_samples, MpegAudioContext::pb, pbBufPtr(), AVCodecContext::priv_data, psycho_acoustic_model(), s, samples, MpegAudioContext::sb_samples, MpegAudioContext::sblimit, SBLIMIT, MpegAudioContext::scale_code, and MpegAudioContext::scale_factors.

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static int MPA_encode_init

(

AVCodecContext *

avctx

)

[static]

Definition at line 64 of file mpegaudio.c.

References a, MpegAudioContext::alloc_table, alloc_tables, av_log(), AV_LOG_DEBUG, AV_LOG_ERROR, avcodec_alloc_frame(), MpegAudioContext::bit_rate, AVCodecContext::bit_rate, bitrate, MpegAudioContext::bitrate_index, AVCodecContext::channels, AVCodecContext::coded_frame, filter_bank, MpegAudioContext::frame_frac, MpegAudioContext::frame_frac_incr, MpegAudioContext::frame_size, AVCodecContext::frame_size, MpegAudioContext::freq, MpegAudioContext::freq_index, l2_select_table(), MpegAudioContext::lsf, mpa_bitrate_tab, mpa_enwindow, MPA_FRAME_SIZE, mpa_freq_tab, MpegAudioContext::nb_channels, P, AVCodecContext::priv_data, quant_bits, s, AVCodecContext::sample_rate, MpegAudioContext::samples_offset, MpegAudioContext::sblimit, sblimit_table, scale_diff_table, scale_factor_mult, scale_factor_shift, scale_factor_table, total_quant_bits, and WFRAC_BITS.

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static void psycho_acoustic_model	(	MpegAudioContext *	s,
		short	smr[SBLIMIT]
	)			[static]

Definition at line 486 of file mpegaudio.c.

References fixed_smr, and MpegAudioContext::sblimit.

Referenced by MPA_encode_frame().