libmpcodecs/ad_pcm.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4
   5 #include "config.h"
   6 #include "ad_internal.h"
   7
   8 static ad_info_t info =
   9 {
  10         "Uncompressed PCM audio decoder",
  11         "pcm",
  12         "Nick Kurshev",
  13         "A'rpi",
  14         ""
  15 };
  16
  17 LIBAD_EXTERN(pcm)
  18
  19 static int init(sh_audio_t *sh_audio)
  20 {
  21   WAVEFORMATEX *h=sh_audio->wf;
  22   sh_audio->i_bps=h->nAvgBytesPerSec;
  23   sh_audio->channels=h->nChannels;
  24   sh_audio->samplerate=h->nSamplesPerSec;
  25   sh_audio->samplesize=(h->wBitsPerSample+7)/8;
  26   switch(sh_audio->format){ /* hardware formats: */
  27     case 0x6:  sh_audio->sample_format=AFMT_A_LAW;break;
  28     case 0x7:  sh_audio->sample_format=AFMT_MU_LAW;break;
  29     case 0x11: sh_audio->sample_format=AFMT_IMA_ADPCM;break;
  30     case 0x50: sh_audio->sample_format=AFMT_MPEG;break;
  31 /*    case 0x2000: sh_audio->sample_format=AFMT_AC3; */
  32     case 0x736F7774: // 'twos'
  33     case 0x74776F73: // 'swot'
  34        if(sh_audio->samplesize==1) sh_audio->sample_format=AFMT_S8;
  35        sh_audio->ds->ss_div= sh_audio->samplesize;
  36        sh_audio->ds->ss_mul= sh_audio->samplesize * sh_audio->channels;
  37        break;
  38     default: if(sh_audio->samplesize!=2) sh_audio->sample_format=AFMT_U8;
  39   }
  40   return 1;
  41 }
  42
  43 static int preinit(sh_audio_t *sh)
  44 {
  45   sh->audio_out_minsize=2048;
  46   return 1;
  47 }
  48
  49 static void uninit(sh_audio_t *sh)
  50 {
  51 }
  52
  53 static int control(sh_audio_t *sh,int cmd,void* arg, ...)
  54 {
  55   int skip;
  56     switch(cmd)
  57     {
  58       case ADCTRL_SKIP_FRAME:
  59         skip=sh->i_bps/16;
  60         skip=skip&(~3);
  61         demux_read_data(sh->ds,NULL,skip);
  62         return CONTROL_TRUE;
  63     }
  64   return CONTROL_UNKNOWN;
  65 }
  66
  67 static int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen)
  68 {
  69   int len=sh_audio->channels*sh_audio->samplesize-1;
  70   len=(minlen+len)&(~len); // sample align
  71   len=demux_read_data(sh_audio->ds,buf,len);
  72 #ifdef WORDS_BIGENDIAN
  73   if(sh_audio->format!=0x736F7774){
  74 #else
  75   if(sh_audio->format==0x736F7774){ // "twos" is swapped byteorder
  76 #endif
  77     int j;
  78     for(j=0;j<len;j+=2){
  79       char x=buf[j];
  80       buf[j]=buf[j+1];
  81       buf[j+1]=x;
  82     }
  83   }
  84   return len;
  85 }