Adding H.264 DCT.

Originally committed as revision 7282 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 81 insertions, 0 deletions

diff --git a/libavcodec/h264dsp.c b/libavcodec/h264dsp.c
new file mode 100644
index 0000000000..4f18afac4a
--- /dev/null
+++ b/libavcodec/h264dsp.c
@@ -0,0 +1,81 @@
+/*
+ * H.264/MPEG-4 Part 10 (Base profile) encoder.
+ *
+ * DSP functions
+ *
+ * Copyright (c) 2006 Expertisecentrum Digitale Media, UHasselt
+ *
+ * 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 h264dsp.c
+ * H.264 encoder related DSP utils
+ *
+ */
+
+#include "dsputil.h"
+
+extern const uint8_t ff_div6[52];
+extern const uint8_t ff_rem6[52];
+
+#define  H264_DCT_PART1(X) \
+         a = block[0][X]+block[3][X]; \
+         c = block[0][X]-block[3][X]; \
+         b = block[1][X]+block[2][X]; \
+         d = block[1][X]-block[2][X]; \
+         pieces[0][X] = a+b; \
+         pieces[2][X] = a-b; \
+         pieces[1][X] = (c<<1)+d; \
+         pieces[3][X] = c-(d<<1);
+
+#define  H264_DCT_PART2(X) \
+         a = pieces[X][0]+pieces[X][3]; \
+         c = pieces[X][0]-pieces[X][3]; \
+         b = pieces[X][1]+pieces[X][2]; \
+         d = pieces[X][1]-pieces[X][2]; \
+         block[0][X] = a+b; \
+         block[2][X] = a-b; \
+         block[1][X] = (c<<1)+d; \
+         block[3][X] = c-(d<<1);
+
+/**
+ * Transform the provided matrix using the H.264 modified DCT.
+ * @note
+ * we'll always work with transposed input blocks, to avoid having to make a
+ * distinction between C and mmx implementations.
+ *
+ * @param block transposed input block
+ */
+static void h264_dct_c(DCTELEM block[4][4])
+{
+    DCTELEM pieces[4][4];
+    DCTELEM a, b, c, d;
+
+    H264_DCT_PART1(0);
+    H264_DCT_PART1(1);
+    H264_DCT_PART1(2);
+    H264_DCT_PART1(3);
+    H264_DCT_PART2(0);
+    H264_DCT_PART2(1);
+    H264_DCT_PART2(2);
+    H264_DCT_PART2(3);
+}
+
+void ff_h264dsp_init(DSPContext* c, AVCodecContext *avctx)
+{
+    c->h264_dct = h264_dct_c;
+}
+