libmpeg3/audio/ac3.c

   1 #include <stdint.h>
   2 #include <stdio.h>
   3
   4 #include <a52dec/a52.h>
   5 #include "mpeg3private.h"
   6 #include "mpeg3protos.h"
   7
   8 #include <string.h>
   9
  10
  11 mpeg3_ac3_t* mpeg3_new_ac3()
  12 {
  13         mpeg3_ac3_t *result = calloc(1, sizeof(mpeg3_ac3_t));
  14         result->stream = mpeg3bits_new_stream(0, 0);
  15         result->state = a52_init(0);
  16         result->output = a52_samples(result->state);
  17         return result;
  18 }
  19
  20 void mpeg3_delete_ac3(mpeg3_ac3_t *audio)
  21 {
  22         mpeg3bits_delete_stream(audio->stream);
  23         a52_free(audio->state);
  24         free(audio);
  25 }
  26
  27
  28 /* Return 1 if it isn't an AC3 header */
  29 int mpeg3_ac3_check(unsigned char *header)
  30 {
  31         int flags, samplerate, bitrate;
  32         return !a52_syncinfo(header,
  33                 &flags,
  34                 &samplerate,
  35                 &bitrate);
  36 }
  37
  38 /* Decode AC3 header */
  39 int mpeg3_ac3_header(mpeg3_ac3_t *audio, unsigned char *header)
  40 {
  41         int result = 0;
  42         audio->flags = 0;
  43
  44 //printf("mpeg3_ac3_header %02x%02x%02x%02x%02x%02x%02x%02x\n", header[0], header[1], header[2], header[3], header[4], header[5], header[6], header[7]);
  45         result = a52_syncinfo(header,
  46                 &audio->flags,
  47         &audio->samplerate,
  48                 &audio->bitrate);
  49
  50
  51         if(result)
  52         {
  53 //printf("%d\n", result);
  54                 audio->framesize = result;
  55                 audio->channels = 0;
  56
  57                 if(audio->flags & A52_LFE)
  58                         audio->channels++;
  59 //printf("mpeg3_ac3_header %02x %02x\n", audio->flags & A52_LFE, audio->flags & A52_CHANNEL_MASK);
  60                 switch(audio->flags & A52_CHANNEL_MASK)
  61                 {
  62                         case A52_CHANNEL:
  63                                 audio->channels++;
  64                                 break;
  65                         case A52_MONO:
  66                                 audio->channels++;
  67                                 break;
  68                         case A52_STEREO:
  69                                 audio->channels += 2;
  70                                 break;
  71                         case A52_3F:
  72                                 audio->channels += 3;
  73                                 break;
  74                         case A52_2F1R:
  75                                 audio->channels += 3;
  76                                 break;
  77                         case A52_3F1R:
  78                                 audio->channels += 4;
  79                                 break;
  80                         case A52_2F2R:
  81                                 audio->channels += 4;
  82                                 break;
  83                         case A52_3F2R:
  84                                 audio->channels += 5;
  85                                 break;
  86                         case A52_DOLBY:
  87                                 audio->channels += 2;
  88                                 break;
  89                         default:
  90                                 printf("mpeg3_ac3_header: unknown channel code: %p\n", audio->flags & A52_CHANNEL_MASK);
  91                                 break;
  92                 }
  93         }
  94 //printf("mpeg3_ac3_header 1 %d\n", audio->channels);
  95         return result;
  96 }
  97
  98
  99 int mpeg3audio_doac3(mpeg3_ac3_t *audio,
 100         char *frame,
 101         int frame_size,
 102         float **output,
 103         int render)
 104 {
 105         int output_position = 0;
 106         sample_t level = 1;
 107         int i, j, k, l;
 108
 109 //printf("mpeg3audio_doac3 1\n");
 110         a52_frame(audio->state,
 111                 frame,
 112                 &audio->flags,
 113                 &level,
 114                 0);
 115 //printf("mpeg3audio_doac3 2\n");
 116         a52_dynrng(audio->state, NULL, NULL);
 117 //printf("mpeg3audio_doac3 3\n");
 118         for(i = 0; i < 6; i++)
 119         {
 120                 if(!a52_block(audio->state))
 121                 {
 122                         l = 0;
 123                         if(render)
 124                         {
 125                                 for(j = 0; j < audio->channels; j++)
 126                                 {
 127                                         for(k = 0; k < 256; k++)
 128                                         {
 129                                                 output[j][output_position + k] = ((sample_t*)audio->output)[l];
 130                                                 l++;
 131                                         }
 132                                 }
 133                         }
 134                         output_position += 256;
 135                 }
 136         }
 137
 138
 139         return output_position;
 140 }
 141
 142
 143