rockbox/apps/codecs/alac.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2005 Dave Chapman
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include "codeclib.h"
#include "libm4a/m4a.h"
#include "libalac/decomp.h"

CODEC_HEADER

#ifdef USE_IRAM
extern char iramcopy[];
extern char iramstart[];
extern char iramend[];
extern char iedata[];
extern char iend[];
#endif

int32_t outputbuffer[ALAC_MAX_CHANNELS][ALAC_BLOCKSIZE] IBSS_ATTR;

struct codec_api* rb;
struct codec_api* ci;

/* this is the codec entry point */
enum codec_status codec_start(struct codec_api* api)
{
  size_t n;
  demux_res_t demux_res;
  stream_t input_stream;
  uint32_t samplesdone;
  uint32_t elapsedtime;
  uint32_t sample_duration;
  uint32_t sample_byte_size;
  int samplesdecoded;
  unsigned int i;
  unsigned char* buffer;
  alac_file alac;
  int retval;

  /* Generic codec initialisation */
  rb = api;
  ci = api;

#ifdef USE_IRAM
  rb->memcpy(iramstart, iramcopy, iramend-iramstart);
  rb->memset(iedata, 0, iend - iedata);
#endif

  ci->configure(CODEC_SET_FILEBUF_WATERMARK, (int *)(1024*512));
  ci->configure(CODEC_SET_FILEBUF_CHUNKSIZE, (int *)(1024*128));

  ci->configure(CODEC_DSP_ENABLE, (bool *)true);
  ci->configure(DSP_DITHER, (bool *)false);
  ci->configure(DSP_SET_STEREO_MODE, (int *)STEREO_NONINTERLEAVED);
  ci->configure(DSP_SET_SAMPLE_DEPTH, (int *)(ALAC_OUTPUT_DEPTH-1));

  next_track:

  if (codec_init(api)) {
    LOGF("ALAC: Error initialising codec\n");
    retval = CODEC_ERROR;
    goto exit;
  }

  while (!rb->taginfo_ready)
    rb->yield();
  
  ci->configure(DSP_SET_FREQUENCY, (long *)(rb->id3->frequency));

  stream_create(&input_stream,ci);

  /* if qtmovie_read returns successfully, the stream is up to
   * the movie data, which can be used directly by the decoder */
  if (!qtmovie_read(&input_stream, &demux_res)) {
    LOGF("ALAC: Error initialising file\n");
    retval = CODEC_ERROR;
    goto exit;
  }

  /* initialise the sound converter */
  create_alac(demux_res.sample_size, demux_res.num_channels,&alac);
  alac_set_info(&alac, demux_res.codecdata);

  i=0;
  samplesdone=0;
  /* The main decoding loop */
  while (i < demux_res.num_sample_byte_sizes) {
    rb->yield();
    if (ci->stop_codec || ci->new_track) {
      break;
    }

    /* Deal with any pending seek requests */
    if (ci->seek_time) {
      if (alac_seek(&demux_res, &input_stream,
                    ((ci->seek_time-1)/10) * (ci->id3->frequency/100),
                    &samplesdone, (int *)&i)) {
        elapsedtime=(samplesdone*10)/(ci->id3->frequency/100);
        ci->set_elapsed(elapsedtime);
      }
      ci->seek_complete();
    }

    /* Lookup the length (in samples and bytes) of block i */
    if (!get_sample_info(&demux_res, i, &sample_duration, 
                         &sample_byte_size)) {
      LOGF("ALAC: Error in get_sample_info\n");
      retval = CODEC_ERROR;
      goto exit;
    }

    /* Request the required number of bytes from the input buffer */

    buffer=ci->request_buffer(&n,sample_byte_size);
    if (n!=sample_byte_size) {
        retval = CODEC_ERROR;
        goto exit;
    }

    /* Decode one block - returned samples will be host-endian */
    rb->yield();
    samplesdecoded=alac_decode_frame(&alac, buffer, outputbuffer, rb->yield);

    /* Advance codec buffer n bytes */
    ci->advance_buffer(n);

    /* Output the audio */
    rb->yield();
    while(!ci->pcmbuf_insert_split(outputbuffer[0],
                                   outputbuffer[1],
                                   samplesdecoded*sizeof(int32_t)))
      rb->yield();

    /* Update the elapsed-time indicator */
    samplesdone+=sample_duration;
    elapsedtime=(samplesdone*10)/(ci->id3->frequency/100);
    ci->set_elapsed(elapsedtime);

    /* Keep track of current position - for resuming */
    ci->set_offset(elapsedtime);

    i++;
  }

  LOGF("ALAC: Decoded %d samples\n",samplesdone);

  if (ci->request_next_track())
   goto next_track;

  retval = CODEC_OK;
exit:
  return retval;
}