extern/ffmpeg/libavcodec/mpegaudio.h

   1 /**
   2  * @file mpegaudio.h
   3  * mpeg audio declarations for both encoder and decoder.
   4  */
   5
   6 /* max frame size, in samples */
   7 #define MPA_FRAME_SIZE 1152
   8
   9 /* max compressed frame size */
  10 #define MPA_MAX_CODED_FRAME_SIZE 1792
  11
  12 #define MPA_MAX_CHANNELS 2
  13
  14 #define SBLIMIT 32 /* number of subbands */
  15
  16 #define MPA_STEREO  0
  17 #define MPA_JSTEREO 1
  18 #define MPA_DUAL    2
  19 #define MPA_MONO    3
  20
  21 /* header + layer + bitrate + freq + lsf/mpeg25 */
  22 #define SAME_HEADER_MASK \
  23    (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
  24
  25 /* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg
  26    audio decoder */
  27
  28 #ifdef USE_HIGHPRECISION
  29 #define FRAC_BITS   23   /* fractional bits for sb_samples and dct */
  30 #define WFRAC_BITS  16   /* fractional bits for window */
  31 #else
  32 #define FRAC_BITS   15   /* fractional bits for sb_samples and dct */
  33 #define WFRAC_BITS  14   /* fractional bits for window */
  34 #endif
  35
  36 #if defined(USE_HIGHPRECISION) && defined(CONFIG_AUDIO_NONSHORT)
  37 typedef int32_t OUT_INT;
  38 #define OUT_MAX INT32_MAX
  39 #define OUT_MIN INT32_MIN
  40 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
  41 #else
  42 typedef int16_t OUT_INT;
  43 #define OUT_MAX INT16_MAX
  44 #define OUT_MIN INT16_MIN
  45 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
  46 #endif
  47
  48 #if FRAC_BITS <= 15
  49 typedef int16_t MPA_INT;
  50 #else
  51 typedef int32_t MPA_INT;
  52 #endif
  53
  54 int l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
  55 int mpa_decode_header(AVCodecContext *avctx, uint32_t head);
  56 void ff_mpa_synth_init(MPA_INT *window);
  57 void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
  58                          MPA_INT *window, int *dither_state,
  59                          OUT_INT *samples, int incr,
  60                          int32_t sb_samples[SBLIMIT]);
  61
  62 extern const uint16_t mpa_bitrate_tab[2][3][15];
  63 extern const uint16_t mpa_freq_tab[3];
  64 extern const unsigned char *alloc_tables[5];
  65 extern const double enwindow[512];
  66 extern const int sblimit_table[5];
  67 extern const int quant_steps[17];
  68 extern const int quant_bits[17];
  69 extern const int32_t mpa_enwindow[257];
  70
  71 /* fast header check for resync */
  72 static inline int ff_mpa_check_header(uint32_t header){
  73     /* header */
  74     if ((header & 0xffe00000) != 0xffe00000)
  75         return -1;
  76     /* layer check */
  77     if ((header & (3<<17)) == 0)
  78         return -1;
  79     /* bit rate */
  80     if ((header & (0xf<<12)) == 0xf<<12)
  81         return -1;
  82     /* frequency */
  83     if ((header & (3<<10)) == 3<<10)
  84         return -1;
  85     return 0;
  86 }