rockbox/apps/codecs/mpc.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2005 Thom Johansen
 *
 * 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 "codec.h"
#include "playback.h"
#include "lib/codeclib.h"
#include <codecs/libmusepack/musepack.h>

static struct codec_api* rb;
mpc_decoder decoder;

/*
  Our implementations of the mpc_reader callback functions.
*/
mpc_int32_t
read_impl(void *data, void *ptr, mpc_int32_t size)
{
  struct codec_api* ci = (struct codec_api*)data;

  return((mpc_int32_t)(ci->read_filebuf(ptr,size)));
}

bool
seek_impl(void *data, mpc_int32_t offset)
{  
  struct codec_api* ci = (struct codec_api*)data;

  /* WARNING: assumes we don't need to skip too far into the past,
     this might not be supported by the buffering layer yet */
  return ci->seek_buffer(offset);
}

mpc_int32_t
tell_impl(void *data)
{
  struct codec_api* ci = (struct codec_api*)data;

  return ci->curpos;
}

mpc_int32_t
get_size_impl(void *data)
{
  struct codec_api* ci = (struct codec_api*)data;
  return ci->filesize;
}

bool
canseek_impl(void *data)
{
    (void)data;
    return false;
}

static int
shift_signed(MPC_SAMPLE_FORMAT val, int shift)
{
  if (shift > 0)
    val <<= shift;
  else if (shift < 0)
    val >>= -shift;
  return (int)val;
}

#define OUTPUT_BUFFER_SIZE 65536 /* Must be an integer multiple of 4. */

unsigned char OutputBuffer[OUTPUT_BUFFER_SIZE];
/* temporary, we probably have better use for iram than this */
MPC_SAMPLE_FORMAT sample_buffer[MPC_DECODER_BUFFER_LENGTH] IDATA_ATTR;
unsigned char *OutputPtr=OutputBuffer;
const unsigned char *OutputBufferEnd=OutputBuffer+OUTPUT_BUFFER_SIZE;

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

/* this is the codec entry point */
enum codec_status codec_start(struct codec_api* api)
{
    struct codec_api* ci = api;
  unsigned short Sample;
  unsigned long samplesdone;
  unsigned long frequency;
  unsigned status = 1;
  unsigned int i;
  mpc_reader reader;

  /* Generic codec inititialisation */

  TEST_CODEC_API(api);
  rb = api;

#ifndef SIMULATOR
  rb->memcpy(iramstart, iramcopy, iramend-iramstart);
#endif

  ci->configure(CODEC_SET_FILEBUF_LIMIT, (int *)(1024*1024*2));
  ci->configure(CODEC_SET_FILEBUF_CHUNKSIZE, (int *)(1024*16));

  next_track:

  if (codec_init(api)) {
    return CODEC_ERROR;
  }

  /* Create a decoder instance */

  reader.read = read_impl;
  reader.seek = seek_impl;
  reader.tell = tell_impl;
  reader.get_size = get_size_impl;
  reader.canseek = canseek_impl;
  reader.data = ci;

  /* read file's streaminfo data */
  mpc_streaminfo info;
  mpc_streaminfo_init(&info);
  if (mpc_streaminfo_read(&info, &reader) != ERROR_CODE_OK) {
    return CODEC_ERROR;  
  }
  frequency=info.sample_freq;

  /* instantiate a decoder with our file reader */
  mpc_decoder_setup(&decoder, &reader);
  if (!mpc_decoder_initialize(&decoder, &info)) {
    return CODEC_ERROR;
  }

  /* Initialise the output buffer. */
  OutputPtr=OutputBuffer;
  OutputBufferEnd=OutputBuffer+OUTPUT_BUFFER_SIZE;

  /* This is the decoding loop. */
  samplesdone=0;
  while (status != 0) {
    if (ci->stop_codec || ci->reload_codec) {
      break;
    }

    status = mpc_decoder_decode(&decoder, sample_buffer, 0, 0);
    if (status == (unsigned)(-1)) {
      //decode error
      return CODEC_ERROR;
    }
    else                    //status>0
    {
    //      file_info.current_sample += status;
    //      file_info.frames_decoded++;
      /* Convert musepack's numbers to an array of 16-bit BE signed integers */
      for(i = 0; i < status*info.channels; i += info.channels)
      {
        /* Left channel */
        Sample=shift_signed(sample_buffer[i], 16 - MPC_FIXED_POINT_SCALE_SHIFT);
        *(OutputPtr++)=Sample>>8;
        *(OutputPtr++)=Sample&0xff;

        /* Right channel. If the decoded stream is monophonic then
         * the right output channel is the same as the left one.
         */
        if(info.channels==2) {
          Sample=shift_signed(sample_buffer[i + 1], 16 - MPC_FIXED_POINT_SCALE_SHIFT);
        }
        *(OutputPtr++)=Sample>>8;
        *(OutputPtr++)=Sample&0xff;

        samplesdone++;

        /* Flush the buffer if it is full. */
        if(OutputPtr==OutputBufferEnd)
        {
          rb->yield();
          while (!ci->audiobuffer_insert(OutputBuffer, OUTPUT_BUFFER_SIZE)) {
            rb->yield();
          }

          ci->set_elapsed(samplesdone/(frequency/1000));
          OutputPtr=OutputBuffer;
        }
      }
    }
  }

  /* Flush the remaining data in the output buffer */
  if (OutputPtr > OutputBuffer) {
    rb->yield();
    while (!ci->audiobuffer_insert(OutputBuffer, OutputPtr-OutputBuffer)) {
      rb->yield();
    }
  }

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

  return CODEC_OK;
}