diff options
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/resampler_down2.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/resampler_down2.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/resampler_down2.c b/lib/rbcodec/codecs/libopus/silk/resampler_down2.c new file mode 100644 index 0000000000..971d7bfd4a --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/resampler_down2.c | |||
@@ -0,0 +1,74 @@ | |||
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_rom.h" | ||
34 | |||
35 | /* Downsample by a factor 2 */ | ||
36 | void silk_resampler_down2( | ||
37 | opus_int32 *S, /* I/O State vector [ 2 ] */ | ||
38 | opus_int16 *out, /* O Output signal [ floor(len/2) ] */ | ||
39 | const opus_int16 *in, /* I Input signal [ len ] */ | ||
40 | opus_int32 inLen /* I Number of input samples */ | ||
41 | ) | ||
42 | { | ||
43 | opus_int32 k, len2 = silk_RSHIFT32( inLen, 1 ); | ||
44 | opus_int32 in32, out32, Y, X; | ||
45 | |||
46 | celt_assert( silk_resampler_down2_0 > 0 ); | ||
47 | celt_assert( silk_resampler_down2_1 < 0 ); | ||
48 | |||
49 | /* Internal variables and state are in Q10 format */ | ||
50 | for( k = 0; k < len2; k++ ) { | ||
51 | /* Convert to Q10 */ | ||
52 | in32 = silk_LSHIFT( (opus_int32)in[ 2 * k ], 10 ); | ||
53 | |||
54 | /* All-pass section for even input sample */ | ||
55 | Y = silk_SUB32( in32, S[ 0 ] ); | ||
56 | X = silk_SMLAWB( Y, Y, silk_resampler_down2_1 ); | ||
57 | out32 = silk_ADD32( S[ 0 ], X ); | ||
58 | S[ 0 ] = silk_ADD32( in32, X ); | ||
59 | |||
60 | /* Convert to Q10 */ | ||
61 | in32 = silk_LSHIFT( (opus_int32)in[ 2 * k + 1 ], 10 ); | ||
62 | |||
63 | /* All-pass section for odd input sample, and add to output of previous section */ | ||
64 | Y = silk_SUB32( in32, S[ 1 ] ); | ||
65 | X = silk_SMULWB( Y, silk_resampler_down2_0 ); | ||
66 | out32 = silk_ADD32( out32, S[ 1 ] ); | ||
67 | out32 = silk_ADD32( out32, X ); | ||
68 | S[ 1 ] = silk_ADD32( in32, X ); | ||
69 | |||
70 | /* Add, convert back to int16 and store to output */ | ||
71 | out[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32, 11 ) ); | ||
72 | } | ||
73 | } | ||
74 | |||