downmix.c

au1200 linux2.6.11 硬件解码mae驱动和maiplayer播放器源码

/* <LIC_AMD_STD>
 * Copyright (C) 2003-2005 Advanced Micro Devices, Inc.  All Rights Reserved.
 * 
 * Unless otherwise designated in writing, this software and any related 
 * documentation are the confidential proprietary information of AMD. 
 * THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT ANY
 * UNLESS OTHERWISE NOTED IN WRITING, EXPRESS OR IMPLIED WARRANTY OF ANY 
 * KIND, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, 
 * NONINFRINGEMENT, TITLE, FITNESS FOR ANY PARTICULAR PURPOSE AND IN NO 
 * EVENT SHALL AMD OR ITS LICENSORS BE LIABLE FOR ANY DAMAGES WHATSOEVER. 
 * 
 * AMD does not assume any responsibility for any errors which may appear 
 * in the Materials nor any responsibility to support or update the
 * Materials.  AMD retains the right to modify the Materials at any time, 
 * without notice, and is not obligated to provide such modified 
 * Materials to you. AMD is not obligated to furnish, support, or make
 * any further information available to you.
 * </LIC_AMD_STD>  */
/* <CTL_AMD_STD>
 * </CTL_AMD_STD>  */
/* <DOC_AMD_STD>
 * Filename: downmix.c
 * </DOC_AMD_STD>  */

#ifdef POSTPROC_DOWNMIX

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "mai_types.h"
#include "../audio_out.h" 
#include "downmix.h" 


#define DPRINTF(_args_)  /* printf _args_ */
#define INFO_PRINTF(_args_) /* printf _args_ */

#if defined(WIN32) || defined(UNDER_CE)
  #if _MSC_VER
    typedef signed __int64 int64_t;
  #else
    typedef signed long long int64_t;
  #endif
#endif

#define FRAC_ONE    (1 << FRAC_BITS)
#define FIX(a)   ((int)((a) * FRAC_ONE))
#define FRAC_BITS   23   /* fractional bits for sb_samples and dct */
#define MULL(a,b) ((int)(((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS))

static short *downmix_buffer;
static char *downmix_input_buffer;


int open_downmix(int buffer_max_size, int number_of_channels)
{
  if (downmix_buffer != NULL)
    free(downmix_buffer);
  if ((downmix_buffer = (short *)malloc(buffer_max_size * sizeof(short) * number_of_channels)) == NULL)
  {
    DPRINTF(("Unable to allocate downmix buffer\n"));
    return -1;
  }
  if (downmix_input_buffer != NULL)
    free(downmix_input_buffer);
  if ((downmix_input_buffer = (char *)malloc(buffer_max_size * sizeof(short) * number_of_channels)) == NULL)
  {
    DPRINTF(("Unable to allocate downmix input buffer\n"));
    return -1;
  }
  INFO_PRINTF(("Downmix %d to 2\n", undownmixed_number_of_channels));
  return 0;
}

short *downmix_to_stereo(short *buf, int *length /* in bytes */) // assumes 16 bits per sample FIXIT
{
  int ii, used;
  int ch_length = *length / (undownmixed_number_of_channels * sizeof(short)); 
  int input_length = *length;
  static int remaining_bytes = 0;

  if (remaining_bytes)
  {
    memcpy(downmix_input_buffer+remaining_bytes, buf, *length);
    *length += remaining_bytes;
    remaining_bytes = 0;
    ch_length = *length / (undownmixed_number_of_channels * 2); 
    input_length = *length;
    buf = (short *)downmix_input_buffer;
  }
  ch_length &= 0xfffff8; /* align to block */

  switch (undownmixed_number_of_channels)
  {
    case 3: /* LF, CF, RF */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[3*ii],   FIX(.5)) + MULL(buf[3*ii+1], FIX(.5));
        downmix_buffer[2*ii + 1] = MULL(buf[3*ii+2], FIX(.5)) + MULL(buf[3*ii+1], FIX(.5));
      }
      break;
    case 4: /* LF, RF, LR, RR */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[4*ii],   FIX(.7)) + MULL(buf[4*ii+2], FIX(.4));
        downmix_buffer[2*ii + 1] = MULL(buf[4*ii+1], FIX(.7)) + MULL(buf[4*ii+3], FIX(.4));
      }
      break;
    case 5: /* LF, CF, RF, LR, RR */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[5*ii],   FIX(.5)) + MULL(buf[5*ii+2], FIX(.4)) + MULL(buf[5*ii+1], FIX(.5));
        downmix_buffer[2*ii + 1] = MULL(buf[5*ii+2], FIX(.5)) + MULL(buf[5*ii+4], FIX(.4)) + MULL(buf[5*ii+1], FIX(.5));
      }
      break;
    case 6: /* LF, CF, RF, LR, RR, LFE  Dolby's order is also used by AAC */
            /*  0  1   2   3   4   5   */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[6*ii],   FIX(.5)) - MULL(buf[6*ii+3], FIX(.4)) + MULL(buf[6*ii+1], FIX(.5)) + MULL(buf[6*ii+5], FIX(.2));
        downmix_buffer[2*ii + 1] = MULL(buf[6*ii+2], FIX(.5)) - MULL(buf[6*ii+4], FIX(.4)) + MULL(buf[6*ii+1], FIX(.5)) + MULL(buf[6*ii+5], FIX(.2));
      }
      break;
    case 7: /* LF, CF, RF, LR, RR, LFE, CR FIXIT this order may not be right */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[7*ii],   FIX(.5)) + MULL(buf[7*ii+2], FIX(.4)) + MULL(buf[7*ii+1], FIX(.5)) + MULL(buf[7*ii+5], FIX(.2)) + MULL(buf[7*ii+6], FIX(.3));
        downmix_buffer[2*ii + 1] = MULL(buf[7*ii+2], FIX(.5)) + MULL(buf[7*ii+4], FIX(.4)) + MULL(buf[7*ii+1], FIX(.5)) + MULL(buf[7*ii+5], FIX(.2)) + MULL(buf[7*ii+6], FIX(.3));
      }
      break;
    case 8: /* LF, RF, CF, LFE, LR, RR, LS, RS */
      /* AVI files do this. See: http://www.microsoft.com/windows/windowsmedia/howto/articles/creating71audio.aspx
      0  Front left  
      1  Front right  
      2  Front center  
      3  Low frequency  
      4  Back left  
      5  Back right  
      6  Side left  
      7  Side right  
      */
      for (ii = 0; ii < ch_length; ii++)
      {
        downmix_buffer[2*ii]     = MULL(buf[7*ii],   FIX(.5)) + MULL(buf[7*ii+2], FIX(.5)) + MULL(buf[7*ii+3], FIX(.2)) - MULL(buf[7*ii+4], FIX(.2)) + MULL(buf[7*ii+6], FIX(.3));
        downmix_buffer[2*ii + 1] = MULL(buf[7*ii+1], FIX(.5)) + MULL(buf[7*ii+2], FIX(.5)) + MULL(buf[7*ii+3], FIX(.2)) - MULL(buf[7*ii+5], FIX(.2)) + MULL(buf[7*ii+7], FIX(.3));
      }
      break;
    default:
      remaining_bytes = 0;
      return buf;
  }
  used = (ch_length * undownmixed_number_of_channels * sizeof(short));
  remaining_bytes = input_length - used;
  memcpy(downmix_input_buffer, ((char *)buf) + input_length - remaining_bytes, remaining_bytes);
  *length = (ch_length * 2 /* channels */ * sizeof(short));
  return downmix_buffer;
}

void close_downmix(void)
{
  if (downmix_buffer != NULL)
    free(downmix_buffer);
  downmix_buffer = NULL;
  if (downmix_input_buffer != NULL)
    free(downmix_input_buffer);
  downmix_input_buffer = NULL;
}

#endif