From da136c7e05246f59d019773d34bbabe66ced517d Mon Sep 17 00:00:00 2001
From: Sascha Sommer <saschasommer@freenet.de>
Date: Sun, 2 Aug 2009 12:57:07 +0000
Subject: add approved hunks of the wmapro decoder

Originally committed as revision 19563 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/wmaprodec.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 libavcodec/wmaprodec.c

(limited to 'libavcodec/wmaprodec.c')

diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
new file mode 100644
index 0000000000..83c8cc5f77
--- /dev/null
+++ b/libavcodec/wmaprodec.c
@@ -0,0 +1,145 @@
+/**
+ *@brief Uninitialize the decoder and free all resources.
+ *@param avctx codec context
+ *@return 0 on success, < 0 otherwise
+ */
+static av_cold int decode_end(AVCodecContext *avctx)
+{
+    WMA3DecodeContext *s = avctx->priv_data;
+    int i;
+
+    av_freep(&s->num_sfb);
+    av_freep(&s->sfb_offsets);
+    av_freep(&s->subwoofer_cutoffs);
+    av_freep(&s->sf_offsets);
+
+    for (i=0 ; i<WMAPRO_BLOCK_SIZES ; i++)
+        ff_mdct_end(&s->mdct_ctx[i]);
+
+    return 0;
+}
+
+/**
+ *@brief Calculate a decorrelation matrix from the bitstream parameters.
+ *@param s codec context
+ *@param chgroup channel group for which the matrix needs to be calculated
+ */
+static void decode_decorrelation_matrix(WMA3DecodeContext* s,
+                                            WMA3ChannelGroup* chgroup)
+{
+    int i;
+    int offset = 0;
+    int8_t rotation_offset[WMAPRO_MAX_CHANNELS * WMAPRO_MAX_CHANNELS];
+    memset(chgroup->decorrelation_matrix,0,
+           sizeof(float) *s->num_channels * s->num_channels);
+
+    for (i=0;i<chgroup->num_channels  * (chgroup->num_channels - 1) >> 1;i++)
+        rotation_offset[i] = get_bits(&s->gb,6);
+
+    for (i=0;i<chgroup->num_channels;i++)
+        chgroup->decorrelation_matrix[chgroup->num_channels * i + i] =
+                                                get_bits1(&s->gb) ? 1.0 : -1.0;
+
+    for (i=1;i<chgroup->num_channels;i++) {
+        int x;
+        for (x=0;x<i;x++) {
+            int y;
+            for (y=0;y < i + 1 ; y++) {
+                float v1 = chgroup->decorrelation_matrix[x * chgroup->num_channels + y];
+                float v2 = chgroup->decorrelation_matrix[i * chgroup->num_channels + y];
+                int n = rotation_offset[offset + x];
+                float sinv;
+                float cosv;
+
+                if (n<32) {
+                    sinv = sin64[n];
+                    cosv = sin64[32-n];
+                } else {
+                    sinv = sin64[64-n];
+                    cosv = -sin64[n-32];
+                }
+
+                chgroup->decorrelation_matrix[y + x * chgroup->num_channels] =
+                                               (v1 * sinv) - (v2 * cosv);
+                chgroup->decorrelation_matrix[y + i * chgroup->num_channels] =
+                                               (v1 * cosv) + (v2 * sinv);
+            }
+        }
+        offset += i;
+    }
+}
+
+/**
+ *@brief Reconstruct the individual channel data.
+ *@param s codec context
+ */
+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) {
+            float data[WMAPRO_MAX_CHANNELS];
+            const int num_channels = s->chgroup[i].num_channels;
+            float** ch_data = s->chgroup[i].channel_data;
+            float** ch_end = ch_data + num_channels;
+            const int8_t* tb = s->chgroup[i].transform_band;
+            int16_t* sfb;
+
+            /** multichannel decorrelation */
+            for (sfb = s->cur_sfb_offsets ;
+                sfb < s->cur_sfb_offsets + s->num_bands;sfb++) {
+                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;
+                        const float* data_end= data + num_channels;
+                        float* data_ptr= data;
+                        float** ch;
+
+                        for (ch = ch_data;ch < ch_end; ch++)
+                           *data_ptr++ = (*ch)[y];
+
+                        for (ch = ch_data; ch < ch_end; ch++) {
+                            float sum = 0;
+                            data_ptr = data;
+                            while (data_ptr < data_end)
+                                sum += *data_ptr++ * *mat++;
+
+                            (*ch)[y] = sum;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
-- 
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