From 4f99c31c3935a8a56b78af26ee0650c8d86d8a5b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 28 Oct 2009 10:51:51 +0000 Subject: Split synth filter out of dca.c. Originally committed as revision 20396 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/synth_filter.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 libavcodec/synth_filter.c (limited to 'libavcodec/synth_filter.c') diff --git a/libavcodec/synth_filter.c b/libavcodec/synth_filter.c new file mode 100644 index 0000000000..3df1a2a8a2 --- /dev/null +++ b/libavcodec/synth_filter.c @@ -0,0 +1,56 @@ +/* + * copyright (c) 2008 Michael Niedermayer + * + * 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 "synth_filter.h" + +void ff_synth_filter_float(FFTContext *imdct, + float *synth_buf_ptr, int *synth_buf_offset, + float synth_buf2[32], const float window[512], + float out[32], const float in[32], float scale, float bias) +{ + float *synth_buf= synth_buf_ptr + *synth_buf_offset; + int i, j; + + ff_imdct_half(imdct, synth_buf, in); + + for (i = 0; i < 16; i++){ + float a= synth_buf2[i ]; + float b= synth_buf2[i+16]; + float c= 0; + float d= 0; + for (j = 0; j < 512 - *synth_buf_offset; j += 64){ + a += window[i+j ]*(-synth_buf[15-i+j]); + b += window[i+j+16]*( synth_buf[ i+j]); + c += window[i+j+32]*( synth_buf[16+i+j]); + d += window[i+j+48]*( synth_buf[31-i+j]); + } + for ( ; j < 512; j += 64){ + a += window[i+j ]*(-synth_buf[15-i+j-512]); + b += window[i+j+16]*( synth_buf[ i+j-512]); + c += window[i+j+32]*( synth_buf[16+i+j-512]); + d += window[i+j+48]*( synth_buf[31-i+j-512]); + } + out[i ] = a * scale + bias; + out[i+16] = b * scale + bias; + synth_buf2[i ] = c; + synth_buf2[i+16] = d; + } + *synth_buf_offset= (*synth_buf_offset-32)&511; +} -- cgit v1.2.3