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/*
* Copyright (c) 2011 Mina Nagy Zaki
*
* 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
*/
/**
* @file
* audio rematrixing functions, based on functions from libavcodec/resample.c
*/
#if defined(FLOATING)
# define DIV2 /2
#else
# define DIV2 >>1
#endif
REMATRIX_FUNC_SIG(stereo_to_mono_packed)
{
while (nb_samples >= 4) {
outp[0][0] = (inp[0][0] + inp[0][1]) DIV2;
outp[0][1] = (inp[0][2] + inp[0][3]) DIV2;
outp[0][2] = (inp[0][4] + inp[0][5]) DIV2;
outp[0][3] = (inp[0][6] + inp[0][7]) DIV2;
outp[0] += 4;
inp[0] += 8;
nb_samples -= 4;
}
while (nb_samples--) {
outp[0][0] = (inp[0][0] + inp[0][1]) DIV2;
outp[0]++;
inp[0] += 2;
}
}
REMATRIX_FUNC_SIG(stereo_downmix_packed)
{
while (nb_samples--) {
*outp[0]++ = inp[0][0];
*outp[0]++ = inp[0][1];
inp[0] += aconvert->in_nb_channels;
}
}
REMATRIX_FUNC_SIG(mono_to_stereo_packed)
{
while (nb_samples >= 4) {
outp[0][0] = outp[0][1] = inp[0][0];
outp[0][2] = outp[0][3] = inp[0][1];
outp[0][4] = outp[0][5] = inp[0][2];
outp[0][6] = outp[0][7] = inp[0][3];
outp[0] += 8;
inp[0] += 4;
nb_samples -= 4;
}
while (nb_samples--) {
outp[0][0] = outp[0][1] = inp[0][0];
outp[0] += 2;
inp[0] += 1;
}
}
/**
* This is for when we have more than 2 input channels, need to downmix to mono
* and do not have a conversion formula available. We just use first two input
* channels - left and right. This is a placeholder until more conversion
* functions are written.
*/
REMATRIX_FUNC_SIG(mono_downmix_packed)
{
while (nb_samples--) {
outp[0][0] = (inp[0][0] + inp[0][1]) DIV2;
inp[0] += aconvert->in_nb_channels;
outp[0]++;
}
}
REMATRIX_FUNC_SIG(mono_downmix_planar)
{
FMT_TYPE *out = outp[0];
while (nb_samples >= 4) {
out[0] = (inp[0][0] + inp[1][0]) DIV2;
out[1] = (inp[0][1] + inp[1][1]) DIV2;
out[2] = (inp[0][2] + inp[1][2]) DIV2;
out[3] = (inp[0][3] + inp[1][3]) DIV2;
out += 4;
inp[0] += 4;
inp[1] += 4;
nb_samples -= 4;
}
while (nb_samples--) {
out[0] = (inp[0][0] + inp[1][0]) DIV2;
out++;
inp[0]++;
inp[1]++;
}
}
/* Stereo to 5.1 output */
REMATRIX_FUNC_SIG(stereo_to_surround_5p1_packed)
{
while (nb_samples--) {
outp[0][0] = inp[0][0]; /* left */
outp[0][1] = inp[0][1]; /* right */
outp[0][2] = (inp[0][0] + inp[0][1]) DIV2; /* center */
outp[0][3] = 0; /* low freq */
outp[0][4] = 0; /* FIXME: left surround: -3dB or -6dB or -9dB of stereo left */
outp[0][5] = 0; /* FIXME: right surroud: -3dB or -6dB or -9dB of stereo right */
inp[0] += 2;
outp[0] += 6;
}
}
REMATRIX_FUNC_SIG(stereo_to_surround_5p1_planar)
{
while (nb_samples--) {
*outp[0]++ = *inp[0]; /* left */
*outp[1]++ = *inp[1]; /* right */
*outp[2]++ = (*inp[0] + *inp[1]) DIV2; /* center */
*outp[3]++ = 0; /* low freq */
*outp[4]++ = 0; /* FIXME: left surround: -3dB or -6dB or -9dB of stereo left */
*outp[5]++ = 0; /* FIXME: right surroud: -3dB or -6dB or -9dB of stereo right */
inp[0]++; inp[1]++;
}
}
/*
5.1 to stereo input: [fl, fr, c, lfe, rl, rr]
- Left = front_left + rear_gain * rear_left + center_gain * center
- Right = front_right + rear_gain * rear_right + center_gain * center
Where rear_gain is usually around 0.5-1.0 and
center_gain is almost always 0.7 (-3 dB)
*/
REMATRIX_FUNC_SIG(surround_5p1_to_stereo_packed)
{
while (nb_samples--) {
*outp[0]++ = inp[0][0] + (0.5 * inp[0][4]) + (0.7 * inp[0][2]); //FIXME CLIPPING!
*outp[0]++ = inp[0][1] + (0.5 * inp[0][5]) + (0.7 * inp[0][2]); //FIXME CLIPPING!
inp[0] += 6;
}
}
REMATRIX_FUNC_SIG(surround_5p1_to_stereo_planar)
{
while (nb_samples--) {
*outp[0]++ = *inp[0] + (0.5 * *inp[4]) + (0.7 * *inp[2]); //FIXME CLIPPING!
*outp[1]++ = *inp[1] + (0.5 * *inp[5]) + (0.7 * *inp[2]); //FIXME CLIPPING!
inp[0]++; inp[1]++; inp[2]++; inp[3]++; inp[4]++; inp[5]++;
}
}
#undef DIV2
#undef REMATRIX_FUNC_NAME
#undef FMT_TYPE
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