mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-21 10:55:51 +02:00
87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
/**
|
|
* @file mpegaudio.h
|
|
* mpeg audio declarations for both encoder and decoder.
|
|
*/
|
|
|
|
/* 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 USE_HIGHPRECISION to have a bit exact (but slower) mpeg
|
|
audio decoder */
|
|
|
|
#ifdef USE_HIGHPRECISION
|
|
#define FRAC_BITS 23 /* fractional bits for sb_samples and dct */
|
|
#define WFRAC_BITS 16 /* fractional bits for window */
|
|
#else
|
|
#define FRAC_BITS 15 /* fractional bits for sb_samples and dct */
|
|
#define WFRAC_BITS 14 /* fractional bits for window */
|
|
#endif
|
|
|
|
#if defined(USE_HIGHPRECISION) && defined(CONFIG_AUDIO_NONSHORT)
|
|
typedef int32_t OUT_INT;
|
|
#define OUT_MAX INT32_MAX
|
|
#define OUT_MIN INT32_MIN
|
|
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
|
|
#else
|
|
typedef int16_t OUT_INT;
|
|
#define OUT_MAX INT16_MAX
|
|
#define OUT_MIN INT16_MIN
|
|
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
|
|
#endif
|
|
|
|
#if FRAC_BITS <= 15
|
|
typedef int16_t MPA_INT;
|
|
#else
|
|
typedef int32_t MPA_INT;
|
|
#endif
|
|
|
|
int l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
|
|
int mpa_decode_header(AVCodecContext *avctx, uint32_t head);
|
|
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,
|
|
int32_t sb_samples[SBLIMIT]);
|
|
|
|
extern const uint16_t mpa_bitrate_tab[2][3][15];
|
|
extern const uint16_t mpa_freq_tab[3];
|
|
extern const unsigned char *alloc_tables[5];
|
|
extern const double enwindow[512];
|
|
extern const int sblimit_table[5];
|
|
extern const int quant_steps[17];
|
|
extern const int quant_bits[17];
|
|
extern const int32_t mpa_enwindow[257];
|
|
|
|
/* 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;
|
|
}
|