PeerStreamer

/*

 * copyright (c) 2001 Fabrice Bellard

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * mpeg audio declarations for both encoder and decoder.

 */

#ifndef AVCODEC_MPEGAUDIO_H

#define AVCODEC_MPEGAUDIO_H

#ifndef CONFIG_FLOAT

#   define CONFIG_FLOAT 0

#endif

#include "avcodec.h"

#include "get_bits.h"

#include "dsputil.h"

#include "dct.h"

/* max frame size, in samples */

#define MPA_FRAME_SIZE 1152

/* max compressed frame size */

#define MPA_MAX_CODED_FRAME_SIZE 1792

#define MPA_MAX_CHANNELS 2

#define SBLIMIT 32 /* number of subbands */

#define MPA_STEREO  0

#define MPA_JSTEREO 1

#define MPA_DUAL    2

#define MPA_MONO    3

/* header + layer + bitrate + freq + lsf/mpeg25 */

#define SAME_HEADER_MASK \

   (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))

#define MP3_MASK 0xFFFE0CCF

#ifndef FRAC_BITS

#define FRAC_BITS   23   /* fractional bits for sb_samples and dct */

#define WFRAC_BITS  16   /* fractional bits for window */

#endif

#define FRAC_ONE    (1 << FRAC_BITS)

#define FIX(a)   ((int)((a) * FRAC_ONE))

#if CONFIG_FLOAT

typedef float OUT_INT;

#define OUT_FMT AV_SAMPLE_FMT_FLT

#else

typedef int16_t OUT_INT;

#define OUT_MAX INT16_MAX

#define OUT_MIN INT16_MIN

#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)

#define OUT_FMT AV_SAMPLE_FMT_S16

#endif

#if CONFIG_FLOAT

#   define INTFLOAT float

typedef float MPA_INT;

#elif FRAC_BITS <= 15

#   define INTFLOAT int

typedef int16_t MPA_INT;

#else

#   define INTFLOAT int

typedef int32_t MPA_INT;

#endif

#define BACKSTEP_SIZE 512

#define EXTRABYTES 24

/* layer 3 "granule" */

typedef struct GranuleDef {

    uint8_t scfsi;

    int part2_3_length;

    int big_values;

    int global_gain;

    int scalefac_compress;

    uint8_t block_type;

    uint8_t switch_point;

    int table_select[3];

    int subblock_gain[3];

    uint8_t scalefac_scale;

    uint8_t count1table_select;

    int region_size[3]; /* number of huffman codes in each region */

    int preflag;

    int short_start, long_end; /* long/short band indexes */

    uint8_t scale_factors[40];

    INTFLOAT sb_hybrid[SBLIMIT * 18]; /* 576 samples */

} GranuleDef;

#define MPA_DECODE_HEADER \

    int frame_size; \

    int error_protection; \

    int layer; \

    int sample_rate; \

    int sample_rate_index; /* between 0 and 8 */ \

    int bit_rate; \

    int nb_channels; \

    int mode; \

    int mode_ext; \

    int lsf;

typedef struct MPADecodeHeader {

  MPA_DECODE_HEADER

} MPADecodeHeader;

typedef struct MPADecodeContext {

    MPA_DECODE_HEADER

    uint8_t last_buf[2*BACKSTEP_SIZE + EXTRABYTES];

    int last_buf_size;

    /* next header (used in free format parsing) */

    uint32_t free_format_next_header;

    GetBitContext gb;

    GetBitContext in_gb;

    DECLARE_ALIGNED(16, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];

    int synth_buf_offset[MPA_MAX_CHANNELS];

    DECLARE_ALIGNED(16, INTFLOAT, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];

    INTFLOAT mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */

    GranuleDef granules[2][2]; /* Used in Layer 3 */

#ifdef DEBUG

    int frame_count;

#endif

    int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3

    int dither_state;

    int error_recognition;

    AVCodecContext* avctx;

#if CONFIG_FLOAT

    DCTContext dct;

#endif

    void (*apply_window_mp3)(MPA_INT *synth_buf, MPA_INT *window,

                             int *dither_state, OUT_INT *samples, int incr);

} MPADecodeContext;

/* layer 3 huffman tables */

typedef struct HuffTable {

    int xsize;

    const uint8_t *bits;

    const uint16_t *codes;

} HuffTable;

int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);

int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);

extern MPA_INT ff_mpa_synth_window[];

void ff_mpa_synth_init(MPA_INT *window);

void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,

                         MPA_INT *window, int *dither_state,

                         OUT_INT *samples, int incr,

                         INTFLOAT sb_samples[SBLIMIT]);

void ff_mpa_synth_init_float(MPA_INT *window);

void ff_mpa_synth_filter_float(MPADecodeContext *s,

                         MPA_INT *synth_buf_ptr, int *synth_buf_offset,

                         MPA_INT *window, int *dither_state,

                         OUT_INT *samples, int incr,

                         INTFLOAT sb_samples[SBLIMIT]);

void ff_mpegaudiodec_init_mmx(MPADecodeContext *s);

void ff_mpegaudiodec_init_altivec(MPADecodeContext *s);

/* fast header check for resync */

static inline int ff_mpa_check_header(uint32_t header){

    /* header */

    if ((header & 0xffe00000) != 0xffe00000)

        return -1;

    /* layer check */

    if ((header & (3<<17)) == 0)

        return -1;

    /* bit rate */

    if ((header & (0xf<<12)) == 0xf<<12)

        return -1;

    /* frequency */

    if ((header & (3<<10)) == 3<<10)

        return -1;

    return 0;

}

#endif /* AVCODEC_MPEGAUDIO_H */