Implement revert_mclms() and associated functions

libavcodec/wmalosslessdec.c

@@ -786,6 +786,93 @@ static void reset_codec(WmallDecodeCtx *s)
 
 
 
+static void mclms_update(WmallDecodeCtx *s, int icoef)
+{
+    int i, j, ich;
+    int16_t pred_error;
+    int order = s->mclms_order;
+    int num_channels = s->num_channels;
+    int16_t range = 1 << (s->bits_per_sample - 1);
+    int bps = s->bits_per_sample > 16 ? 4 : 2; // bytes per sample
+
+    for (ich = 0; ich < num_channels; ich++) {
+        pred_error = s->channel_coeffs[ich][icoef] -
+                     s->channel_residues[ich][icoef];
+        if (pred_error > 0) {
+            for (i = 0; i < order * num_channels; i++)
+                s->mclms_coeffs[i + ich * order * num_channels] +=
+                    s->mclms_updates[s->mclms_recent + i];
+            for (j = 0; j < i; j++) {
+                if (s->channel_coeffs[ich][icoef] > 0)
+                    s->mclms_coeffs_cur[ich * num_channels + j] += 1;
+                else if (s->channel_coeffs[ich][icoef] < 0)
+                    s->mclms_coeffs_cur[ich * num_channels + j] -= 1;
+            }
+        } else if (pred_error < 0) {
+            for (i = 0; i < order * num_channels; i++)
+                s->mclms_coeffs[i + ich * order * num_channels] -=
+                    s->mclms_updates[s->mclms_recent + i];
+            for (j = 0; j < i; j++) {
+                if (s->channel_coeffs[ich][icoef] > 0)
+                    s->mclms_coeffs_cur[ich * num_channels + j] -= 1;
+                else if (s->channel_coeffs[ich][icoef] < 0)
+                    s->mclms_coeffs_cur[ich * num_channels + j] += 1;
+            }
+        }
+    }
+
+    for (ich = num_channels - 1; ich >= 0; ich--) {
+        s->mclms_recent--;
+        if (s->channel_coeffs[ich][icoef] > range - 1)
+            s->mclms_prevvalues[s->mclms_recent] = range - 1;
+        else if (s->channel_coeffs[ich][icoef] <= -range)
+            s->mclms_prevvalues[s->mclms_recent] = -range;
+
+        s->mclms_updates[s->mclms_recent] =
+            av_clip(-1, s->channel_coeffs[ich][icoef], 1);
+    }
+
+    if (s->mclms_recent == 0) {
+        memcpy(s->mclms_prevvalues[order * num_channels],
+               s->mclms_prevvalues,
+               bps * order * num_channels);
+        memcpy(s->mclms_updates[order * num_channels],
+               s->mclms_updates,
+               bps * order * num_channels);
+        s->mclms_recent = num_channels * order;
+    }
+}
+static void mclms_predict(WmallDecodeCtx *s, int icoef)
+{
+    int ich, i;
+    int16_t pred;
+    int order = s->mclms_order;
+    int num_channels = s->num_channels;
+
+    for (ich = 0; ich < num_channels; ich++) {
+        if (!s->is_channel_coded[ich])
+            continue;
+        pred = 0;
+        for (i = 0; i < order * num_channels; i++)
+            pred += s->mclms_prevvalues[i] *
+                    s->mclms_coeffs[i + order * num_channels * ich];
+        for (i = 0; i < ich; i++)
+            pred += s->channel_coeffs[ich][icoef] *
+                    s->mclms_coeffs_cur[i + order * num_channels * ich];
+        s->channel_coeffs[ich][icoef] =
+                    s->channel_residues[ich][icoef] + pred;
+    }
+}
+
+static void revert_mclms(WmallDecodeCtx *s, int tile_size)
+{
+    int icoef;
+    for (icoef = 0; icoef < tile_size; icoef++) {
+        mclms_predict(s, icoef);
+        mclms_update(s, icoef);
+    }
+}
+
 static int lms_predict(WmallDecodeCtx *s, int ich, int ilms)
 {
     int16_t pred = 0, icoef;