From f53e96ed4170425ea70f818ea600b7a5f2a026d7 Mon Sep 17 00:00:00 2001 From: Sascha Sommer Date: Wed, 26 Aug 2009 21:18:54 +0000 Subject: [PATCH] merge 2-channel M/S stereo decoding code with the multichannel version Originally committed as revision 19718 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/wmaprodec.c | 36 +++++++----------------------------- 1 file changed, 7 insertions(+), 29 deletions(-) diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c index 7deb56f981..8f48aff8ad 100644 --- a/libavcodec/wmaprodec.c +++ b/libavcodec/wmaprodec.c @@ -161,34 +161,7 @@ static void inverse_channel_transform(WMA3DecodeContext *s) int i; for (i = 0; i < s->num_chgroups; i++) { - - if (s->chgroup[i].transform == 1) { - /** M/S stereo decoding */ - int16_t* sfb_offsets = s->cur_sfb_offsets; - float* ch0 = *sfb_offsets + s->channel[0].coeffs; - float* ch1 = *sfb_offsets++ + s->channel[1].coeffs; - const char* tb = s->chgroup[i].transform_band; - const char* tb_end = tb + s->num_bands; - - while (tb < tb_end) { - const float* ch0_end = s->channel[0].coeffs + - FFMIN(*sfb_offsets, s->subframe_len); - if (*tb++ == 1) { - while (ch0 < ch0_end) { - const float v1 = *ch0; - const float v2 = *ch1; - *ch0++ = v1 - v2; - *ch1++ = v1 + v2; - } - } else { - while (ch0 < ch0_end) { - *ch0++ *= 181.0 / 128; - *ch1++ *= 181.0 / 128; - } - } - ++sfb_offsets; - } - } else if (s->chgroup[i].transform) { + if (s->chgroup[i].transform) { float data[WMAPRO_MAX_CHANNELS]; const int num_channels = s->chgroup[i].num_channels; float** ch_data = s->chgroup[i].channel_data; @@ -199,8 +172,8 @@ static void inverse_channel_transform(WMA3DecodeContext *s) /** multichannel decorrelation */ for (sfb = s->cur_sfb_offsets; sfb < s->cur_sfb_offsets + s->num_bands;sfb++) { + int y; if (*tb++ == 1) { - int y; /** multiply values with the decorrelation_matrix */ for (y = sfb[0]; y < FFMIN(sfb[1], s->subframe_len); y++) { const float* mat = s->chgroup[i].decorrelation_matrix; @@ -220,6 +193,11 @@ static void inverse_channel_transform(WMA3DecodeContext *s) (*ch)[y] = sum; } } + } else if (s->num_channels == 2) { + for (y = sfb[0]; y < FFMIN(sfb[1], s->subframe_len); y++) { + ch_data[0][y] *= 181.0 / 128; + ch_data[1][y] *= 181.0 / 128; + } } } }