rv34: DC-only inverse transform

When decoding coefficients, detect whether the block is DC-only, and take
advantage of this knowledge to perform DC-only inverse transform.

This is achieved by:
- first, changing the 108x4 element modulo_three_table into a 108 element
  table (kind of base4), and accessing each value using mask and shifts.
- then, checking low bits for 0 (as they represent the presence of higher
  frequency coefficients)

Also provide x86 SIMD code for the DC-only inverse transform.

Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>

3 files changed, 100 insertions, 1 deletions

diff --git a/libavcodec/x86/Makefile b/libavcodec/x86/Makefile
index 2abe4fbe72..1e88e4a847 100644
--- a/libavcodec/x86/Makefile
+++ b/libavcodec/x86/Makefile
@@ -24,7 +24,11 @@ YASM-OBJS-$(CONFIG_H264PRED)           += x86/h264_intrapred.o          \
                                           x86/h264_intrapred_10bit.o
 MMX-OBJS-$(CONFIG_H264PRED)            += x86/h264_intrapred_init.o
 
-MMX-OBJS-$(CONFIG_RV40_DECODER)        += x86/rv40dsp.o                 \
+MMX-OBJS-$(CONFIG_RV30_DECODER)        += x86/rv34dsp_init.o
+YASM-OBJS-$(CONFIG_RV30_DECODER)       += x86/rv34dsp.o
+MMX-OBJS-$(CONFIG_RV40_DECODER)        += x86/rv34dsp_init.o            \
+                                          x86/rv40dsp.o
+YASM-OBJS-$(CONFIG_RV40_DECODER)       += x86/rv34dsp.o
 
 YASM-OBJS-$(CONFIG_VC1_DECODER)        += x86/vc1dsp_yasm.o
 
diff --git a/libavcodec/x86/rv34dsp.asm b/libavcodec/x86/rv34dsp.asm
new file mode 100644
index 0000000000..58f1af0495
--- /dev/null
+++ b/libavcodec/x86/rv34dsp.asm
@@ -0,0 +1,55 @@
+;******************************************************************************
+;* MMX/SSE2-optimized functions for the RV30 and RV40 decoders
+;* Copyright (C) 2012 Christophe Gisquet <christophe.gisquet@gmail.com>
+;*
+;* This file is part of Libav.
+;*
+;* Libav 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.
+;*
+;* Libav 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 Libav; if not, write to the Free Software
+;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+;******************************************************************************
+
+%include "x86inc.asm"
+%include "x86util.asm"
+
+SECTION .text
+
+%macro IDCT_DC_NOROUND 1
+    imul   %1, 13*13*3
+    sar    %1, 11
+%endmacro
+
+%macro IDCT_DC_ROUND 1
+    imul   %1, 13*13
+    add    %1, 0x200
+    sar    %1, 10
+%endmacro
+
+%macro rv34_idct_dequant4x4_dc 1
+cglobal rv34_idct_dequant4x4_%1_mmx2, 1, 2, 0
+    movsx   r1, word [r0]
+    IDCT_DC r1
+    movd    mm0, r1
+    pshufw  mm0, mm0, 0
+    movq    [r0+ 0], mm0
+    movq    [r0+16], mm0
+    movq    [r0+32], mm0
+    movq    [r0+48], mm0
+    REP_RET
+%endmacro
+
+INIT_MMX
+%define IDCT_DC IDCT_DC_ROUND
+rv34_idct_dequant4x4_dc dc
+%define IDCT_DC IDCT_DC_NOROUND
+rv34_idct_dequant4x4_dc dc_noround
diff --git a/libavcodec/x86/rv34dsp_init.c b/libavcodec/x86/rv34dsp_init.c
new file mode 100644
index 0000000000..4317e9b23b
--- /dev/null
+++ b/libavcodec/x86/rv34dsp_init.c
@@ -0,0 +1,40 @@
+/*
+ * RV30/40 MMX/SSE2 optimizations
+ * Copyright (C) 2012 Christophe Gisquet <christophe.gisquet@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/cpu.h"
+#include "libavutil/x86_cpu.h"
+#include "libavcodec/dsputil.h"
+#include "libavcodec/rv34dsp.h"
+
+void ff_rv34_idct_dequant4x4_dc_mmx2(DCTELEM *block);
+void ff_rv34_idct_dequant4x4_dc_noround_mmx2(DCTELEM *block);
+
+av_cold void ff_rv34dsp_init_x86(RV34DSPContext* c, DSPContext *dsp)
+{
+#if HAVE_YASM
+    int mm_flags = av_get_cpu_flags();
+
+    if (mm_flags & AV_CPU_FLAG_MMX2) {
+        c->rv34_inv_transform_dc_tab[0] = ff_rv34_idct_dequant4x4_dc_mmx2;
+        c->rv34_inv_transform_dc_tab[1] = ff_rv34_idct_dequant4x4_dc_noround_mmx2;
+    }
+#endif
+}