DCA: break out lfe_interpolation_fir() inner loops to a function

This enables SIMD optimisations of this function.

Originally committed as revision 22861 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 49 insertions, 0 deletions

diff --git a/libavcodec/dcadsp.c b/libavcodec/dcadsp.c
new file mode 100644
index 0000000000..fcd3b85451
--- /dev/null
+++ b/libavcodec/dcadsp.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2004 Gildas Bazin
+ * Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
+ *
+ * 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 "dcadsp.h"
+
+static void dca_lfe_fir_c(float *out, const float *in, const float *coefs,
+                          int decifactor, float scale, float bias)
+{
+    float *out2 = out + decifactor;
+    const float *cf0 = coefs;
+    const float *cf1 = coefs + 256;
+    int j, k;
+
+    /* One decimated sample generates 2*decifactor interpolated ones */
+    for (k = 0; k < decifactor; k++) {
+        float v0 = 0.0;
+        float v1 = 0.0;
+        for (j = 0; j < 256 / decifactor; j++) {
+            float s = in[-j];
+            v0 += s * *cf0++;
+            v1 += s * *--cf1;
+        }
+        *out++  = (v0 * scale) + bias;
+        *out2++ = (v1 * scale) + bias;
+    }
+}
+
+void ff_dcadsp_init(DCADSPContext *s)
+{
+    s->lfe_fir = dca_lfe_fir_c;
+}