Line data    Source code

       1             : /***********************************************************************
       2             : Copyright (c) 2006-2011, Skype Limited. All rights reserved.
       3             : Redistribution and use in source and binary forms, with or without
       4             : modification, are permitted provided that the following conditions
       5             : are met:
       6             : - Redistributions of source code must retain the above copyright notice,
       7             : this list of conditions and the following disclaimer.
       8             : - Redistributions in binary form must reproduce the above copyright
       9             : notice, this list of conditions and the following disclaimer in the
      10             : documentation and/or other materials provided with the distribution.
      11             : - Neither the name of Internet Society, IETF or IETF Trust, nor the
      12             : names of specific contributors, may be used to endorse or promote
      13             : products derived from this software without specific prior written
      14             : permission.
      15             : THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
      16             : AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      17             : IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      18             : ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
      19             : LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
      20             : CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
      21             : SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      22             : INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
      23             : CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      24             : ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
      25             : POSSIBILITY OF SUCH DAMAGE.
      26             : ***********************************************************************/
      27             : 
      28             : #ifdef HAVE_CONFIG_H
      29             : #include "config.h"
      30             : #endif
      31             : 
      32             : #include "SigProc_FIX.h"
      33             : #include "resampler_private.h"
      34             : #include "stack_alloc.h"
      35             : 
      36             : #define ORDER_FIR                   4
      37             : 
      38             : /* Downsample by a factor 2/3, low quality */
      39           0 : void silk_resampler_down2_3(
      40             :     opus_int32                  *S,                 /* I/O  State vector [ 6 ]                                          */
      41             :     opus_int16                  *out,               /* O    Output signal [ floor(2*inLen/3) ]                          */
      42             :     const opus_int16            *in,                /* I    Input signal [ inLen ]                                      */
      43             :     opus_int32                  inLen               /* I    Number of input samples                                     */
      44             : )
      45             : {
      46             :     opus_int32 nSamplesIn, counter, res_Q6;
      47             :     VARDECL( opus_int32, buf );
      48             :     opus_int32 *buf_ptr;
      49             :     SAVE_STACK;
      50             : 
      51           0 :     ALLOC( buf, RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR, opus_int32 );
      52             : 
      53             :     /* Copy buffered samples to start of buffer */
      54           0 :     silk_memcpy( buf, S, ORDER_FIR * sizeof( opus_int32 ) );
      55             : 
      56             :     /* Iterate over blocks of frameSizeIn input samples */
      57             :     while( 1 ) {
      58           0 :         nSamplesIn = silk_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN );
      59             : 
      60             :         /* Second-order AR filter (output in Q8) */
      61           0 :         silk_resampler_private_AR2( &S[ ORDER_FIR ], &buf[ ORDER_FIR ], in,
      62             :             silk_Resampler_2_3_COEFS_LQ, nSamplesIn );
      63             : 
      64             :         /* Interpolate filtered signal */
      65           0 :         buf_ptr = buf;
      66           0 :         counter = nSamplesIn;
      67           0 :         while( counter > 2 ) {
      68             :             /* Inner product */
      69           0 :             res_Q6 = silk_SMULWB(         buf_ptr[ 0 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
      70           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
      71           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
      72           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
      73             : 
      74             :             /* Scale down, saturate and store in output array */
      75           0 :             *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
      76             : 
      77           0 :             res_Q6 = silk_SMULWB(         buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
      78           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
      79           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
      80           0 :             res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 4 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
      81             : 
      82             :             /* Scale down, saturate and store in output array */
      83           0 :             *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
      84             : 
      85           0 :             buf_ptr += 3;
      86           0 :             counter -= 3;
      87             :         }
      88             : 
      89           0 :         in += nSamplesIn;
      90           0 :         inLen -= nSamplesIn;
      91             : 
      92           0 :         if( inLen > 0 ) {
      93             :             /* More iterations to do; copy last part of filtered signal to beginning of buffer */
      94           0 :             silk_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
      95             :         } else {
      96           0 :             break;
      97             :         }
      98             :     }
      99             : 
     100             :     /* Copy last part of filtered signal to the state for the next call */
     101           0 :     silk_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
     102             :     RESTORE_STACK;
     103           0 : }