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author | Kenan Gillet <kenan.gillet@gmail.com> | 2008-10-24 21:29:23 +0000 |
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committer | Diego Biurrun <diego@biurrun.de> | 2008-10-24 21:29:23 +0000 |
commit | 4599d22c0cd7fa952bc02375d2899d8c9a31b9ae (patch) | |
tree | 23797fb97eb41bdfd65c7d2fbfdb7c5d1c0562dd /libavcodec/celp_filters.c | |
parent | 60c25a4beb1d0df699104ecb8a536d9a09703d2f (diff) | |
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Split off celp_filters.[ch] from acelp_filters.[ch] for the QCELP decoder.
patch by Kenan Gillet, kenan.gillet gmail com
Originally committed as revision 15680 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/celp_filters.c')
-rw-r--r-- | libavcodec/celp_filters.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/libavcodec/celp_filters.c b/libavcodec/celp_filters.c new file mode 100644 index 0000000000..758c9b0a90 --- /dev/null +++ b/libavcodec/celp_filters.c @@ -0,0 +1,86 @@ +/* + * various filters for ACELP-based codecs + * + * Copyright (c) 2008 Vladimir Voroshilov + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <inttypes.h> + +#include "avcodec.h" +#include "celp_filters.h" + +void ff_celp_convolve_circ( + int16_t* fc_out, + const int16_t* fc_in, + const int16_t* filter, + int len) +{ + int i, k; + + memset(fc_out, 0, len * sizeof(int16_t)); + + /* Since there are few pulses over an entire subframe (i.e. almost + all fc_in[i] are zero) it is faster to loop over fc_in first. */ + for(i=0; i<len; i++) + { + if(fc_in[i]) + { + for(k=0; k<i; k++) + fc_out[k] += (fc_in[i] * filter[len + k - i]) >> 15; + + for(k=i; k<len; k++) + fc_out[k] += (fc_in[i] * filter[ k - i]) >> 15; + } + } +} + +int ff_celp_lp_synthesis_filter( + int16_t *out, + const int16_t* filter_coeffs, + const int16_t* in, + int buffer_length, + int filter_length, + int stop_on_overflow, + int rounder) +{ + int i,n; + + // These two lines are to avoid a -1 subtraction in the main loop + filter_length++; + filter_coeffs--; + + for(n=0; n<buffer_length; n++) + { + int sum = rounder; + for(i=1; i<filter_length; i++) + sum -= filter_coeffs[i] * out[n-i]; + + sum = (sum >> 12) + in[n]; + + if(sum + 0x8000 > 0xFFFFU) + { + if(stop_on_overflow) + return 1; + sum = (sum >> 31) ^ 32767; + } + out[n] = sum; + } + + return 0; +} |