apps/codecs/a52_rm.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id:$
   9  *
  10  * Copyright (C) 2009 Mohamed Tarek
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include "codeclib.h"
  23 #include <codecs/librm/rm.h>
  24 #include <inttypes.h>  /* Needed by a52.h */
  25 #include <codecs/liba52/config-a52.h>
  26 #include <codecs/liba52/a52.h>
  27
  28 CODEC_HEADER
  29
  30 #define BUFFER_SIZE 4096
  31
  32 #define A52_SAMPLESPERFRAME (6*256)
  33
  34 static a52_state_t *state;
  35 unsigned long samplesdone;
  36 unsigned long frequency;
  37 RMContext rmctx;
  38 RMPacket pkt;
  39
  40 static void init_rm(RMContext *rmctx)
  41 {
  42     memcpy(rmctx, (void*)(( (intptr_t)ci->id3->id3v2buf + 3 ) &~ 3), sizeof(RMContext));
  43 }
  44
  45 /* used outside liba52 */
  46 static uint8_t buf[3840] IBSS_ATTR;
  47
  48 static inline void output_audio(sample_t *samples)
  49 {
  50     ci->yield();
  51     ci->pcmbuf_insert(&samples[0], &samples[256], 256);
  52 }
  53
  54 static void a52_decode_data(uint8_t *start, uint8_t *end)
  55 {
  56     static uint8_t *bufptr = buf;
  57     static uint8_t *bufpos = buf + 7;
  58     /*
  59      * sample_rate and flags are static because this routine could
  60      * exit between the a52_syncinfo() and the ao_setup(), and we want
  61      * to have the same values when we get back !
  62      */
  63     static int sample_rate;
  64     static int flags;
  65     int bit_rate;
  66     int len;
  67
  68     while (1) {
  69         len = end - start;
  70         if (!len)
  71             break;
  72         if (len > bufpos - bufptr)
  73             len = bufpos - bufptr;
  74         memcpy(bufptr, start, len);
  75         bufptr += len;
  76         start += len;
  77         if (bufptr == bufpos) {
  78             if (bufpos == buf + 7) {
  79                 int length;
  80
  81                 length = a52_syncinfo(buf, &flags, &sample_rate, &bit_rate);
  82                 if (!length) {
  83                     //DEBUGF("skip\n");
  84                     for (bufptr = buf; bufptr < buf + 6; bufptr++)
  85                         bufptr[0] = bufptr[1];
  86                     continue;
  87                 }
  88                 bufpos = buf + length;
  89             } else {
  90                 /* Unity gain is 1 << 26, and we want to end up on 28 bits
  91                    of precision instead of the default 30.
  92                  */
  93                 level_t level = 1 << 24;
  94                 sample_t bias = 0;
  95                 int i;
  96
  97                 /* This is the configuration for the downmixing: */
  98                 flags = A52_STEREO | A52_ADJUST_LEVEL;
  99
 100                 if (a52_frame(state, buf, &flags, &level, bias))
 101                     goto error;
 102                 a52_dynrng(state, NULL, NULL);
 103                 frequency = sample_rate;
 104
 105                 /* An A52 frame consists of 6 blocks of 256 samples
 106                    So we decode and output them one block at a time */
 107                 for (i = 0; i < 6; i++) {
 108                     if (a52_block(state))
 109                         goto error;
 110                     output_audio(a52_samples(state));
 111                     samplesdone += 256;
 112                 }
 113                 ci->set_elapsed(samplesdone/(frequency/1000));
 114                 bufptr = buf;
 115                 bufpos = buf + 7;
 116                 continue;
 117             error:
 118                 //logf("Error decoding A52 stream\n");
 119                 bufptr = buf;
 120                 bufpos = buf + 7;
 121             }
 122         }
 123     }
 124 }
 125
 126
 127 /* this is the codec entry point */
 128 enum codec_status codec_main(void)
 129 {
 130     size_t n;
 131     uint8_t *filebuf;
 132     int retval, consumed, packet_offset;
 133
 134     /* Generic codec initialisation */
 135     ci->configure(DSP_SET_STEREO_MODE, STEREO_NONINTERLEAVED);
 136     ci->configure(DSP_SET_SAMPLE_DEPTH, 28);
 137
 138 next_track:
 139     if (codec_init()) {
 140         retval = CODEC_ERROR;
 141         goto exit;
 142     }
 143
 144     while (!ci->taginfo_ready)
 145         ci->yield();
 146
 147     ci->configure(DSP_SWITCH_FREQUENCY, ci->id3->frequency);
 148     codec_set_replaygain(ci->id3);
 149
 150     /* Intializations */
 151     state = a52_init(0);
 152     ci->memset(&rmctx,0,sizeof(RMContext));
 153     ci->memset(&pkt,0,sizeof(RMPacket));
 154     init_rm(&rmctx);
 155
 156     /* Seek to the first packet */
 157     ci->advance_buffer(rmctx.data_offset + DATA_HEADER_SIZE );
 158
 159     /* The main decoding loop */
 160     while(pkt.timestamp < rmctx.duration) {
 161         ci->yield();
 162         if (ci->stop_codec || ci->new_track)
 163             break;
 164
 165         if (ci->seek_time) {
 166             packet_offset = ci->seek_time / (((rmctx.block_align + PACKET_HEADER_SIZE)*8*1000)/rmctx.bit_rate);
 167             ci->seek_buffer(rmctx.data_offset + DATA_HEADER_SIZE + packet_offset*(rmctx.block_align + PACKET_HEADER_SIZE));
 168             samplesdone = A52_SAMPLESPERFRAME * packet_offset;
 169             ci->seek_complete();
 170         }
 171
 172         filebuf = ci->request_buffer(&n, rmctx.block_align + PACKET_HEADER_SIZE);
 173         consumed = rm_get_packet(&filebuf, &rmctx, &pkt);
 174         if(consumed < 0) {
 175             DEBUGF("rm_get_packet failed\n");
 176             return CODEC_ERROR;
 177         }
 178         a52_decode_data(filebuf, filebuf + rmctx.block_align);
 179         ci->advance_buffer(pkt.length);
 180     }
 181
 182     retval = CODEC_OK;
 183
 184     if (ci->request_next_track())
 185         goto next_track;
 186
 187 exit:
 188     a52_free(state);
 189     return retval;
 190 }