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comparison: media/libopus/silk/resampler_down2_3.c
media/libopus/silk/resampler_down2_3.c
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| 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 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 ALLOC( buf, RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR, opus_int32 ); | |
| 52 | |
| 53 /* Copy buffered samples to start of buffer */ | |
| 54 silk_memcpy( buf, S, ORDER_FIR * sizeof( opus_int32 ) ); | |
| 55 | |
| 56 /* Iterate over blocks of frameSizeIn input samples */ | |
| 57 while( 1 ) { | |
| 58 nSamplesIn = silk_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN ); | |
| 59 | |
| 60 /* Second-order AR filter (output in Q8) */ | |
| 61 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 buf_ptr = buf; | |
| 66 counter = nSamplesIn; | |
| 67 while( counter > 2 ) { | |
| 68 /* Inner product */ | |
| 69 res_Q6 = silk_SMULWB( buf_ptr[ 0 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] ); | |
| 70 res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] ); | |
| 71 res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] ); | |
| 72 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 *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) ); | |
| 76 | |
| 77 res_Q6 = silk_SMULWB( buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] ); | |
| 78 res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] ); | |
| 79 res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] ); | |
| 80 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 *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) ); | |
| 84 | |
| 85 buf_ptr += 3; | |
| 86 counter -= 3; | |
| 87 } | |
| 88 | |
| 89 in += nSamplesIn; | |
| 90 inLen -= nSamplesIn; | |
| 91 | |
| 92 if( inLen > 0 ) { | |
| 93 /* More iterations to do; copy last part of filtered signal to beginning of buffer */ | |
| 94 silk_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) ); | |
| 95 } else { | |
| 96 break; | |
| 97 } | |
| 98 } | |
| 99 | |
| 100 /* Copy last part of filtered signal to the state for the next call */ | |
| 101 silk_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) ); | |
| 102 RESTORE_STACK; | |
| 103 } |
