X-Git-Url: http://git.maemo.org/git/?a=blobdiff_plain;ds=sidebyside;f=mardrone%2FARDrone_SDK_Version_1_8_20110726%2FARDroneLib%2FVLIB%2FP264%2Fp264_Qp.c;fp=mardrone%2FARDrone_SDK_Version_1_8_20110726%2FARDroneLib%2FVLIB%2FP264%2Fp264_Qp.c;h=ecf8431e8f716004c7f105fc67e133790f6a3a97;hb=9ec9bc13b75d30bc45535c54a652934debfcea92;hp=0000000000000000000000000000000000000000;hpb=ae0a3c2dc0898400aca0dd6b439c5db8044db7b2;p=mardrone

diff --git a/mardrone/ARDrone_SDK_Version_1_8_20110726/ARDroneLib/VLIB/P264/p264_Qp.c b/mardrone/ARDrone_SDK_Version_1_8_20110726/ARDroneLib/VLIB/P264/p264_Qp.c
new file mode 100644
index 0000000..ecf8431
--- /dev/null
+++ b/mardrone/ARDrone_SDK_Version_1_8_20110726/ARDroneLib/VLIB/P264/p264_Qp.c
@@ -0,0 +1,126 @@
+#include <VLIB/P264/p264_Qp.h>
+
+// define QP_core_table used to scale p264 4x4 transform coefficients
+// QP is the quantizer parameter varying from 0 to 51.
+// p264 rescaling rules :
+// - luma 4x4 residual block -> use Coeff*QP%6_core_table * 2^(floor(QP/6))
+//
+// - 4x4 luma DC block       -> use Coeff*QP%6_core_table[0] * 2^(floor(QP/6)-2)                     (Qp>=12)
+//                           -> use [Coeff*QP%6_core_table[0] + 2^(1-floor(QP/6)] >> (2-floor(QP/6)) (Qp<12)
+//
+// - 2x2 chroma DC block     -> use Coeff*QP%6_core_table[0] / 2                  (Qp<6)
+//                           -> use Coeff*QP%6_core_table[0] * 2^(floor(QP/6)-1)  (Qp>=6)
+
+static uint16_t QP_core_table[6][16] = {
+// QP0 : Qstep0 * Si (* 2^6)
+{
+ 10, 13, 10, 13,
+ 13, 16, 13, 16,
+ 10, 13, 10, 13,
+ 13, 16, 13, 16
+},
+// QP1 : Qstep1 * Si (* 2^6)
+{
+ 11, 14, 11, 14,
+ 14, 18, 14, 18,
+ 11, 14, 11, 14,
+ 14, 18, 14, 18
+},
+// QP2 : Qstep2 * Si (* 2^6)
+{
+  13, 16, 13, 16,
+  16, 20, 16, 20,
+  13, 16, 13, 16,
+  16, 20, 16, 20
+},
+// QP3 : Qstep3 * Si (* 2^6)
+{
+  14, 18, 14, 18,
+  18, 23, 18, 23,
+  14, 18, 14, 18,
+  18, 23, 18, 23
+},
+// QP4 : Qstep4 * Si (* 2^6)
+{
+  16, 20, 16, 20,
+  20, 25, 20, 25,
+  16, 20, 16, 20,
+  20, 25, 20, 25
+},
+// QP5 : Qstep5 * Si (* 2^6)
+{
+  18, 23, 18, 23,
+  23, 29, 23, 29,
+  18, 23, 18, 23,
+  23, 29, 23, 29
+}
+};
+
+
+void p264_4x4_residual_scale(int16_t* in, int16_t* out, uint32_t Qp)
+// validate for several Qp on one value block
+{
+  // rescaling rules :
+  // - luma 4x4 residual block -> use Coeff*QP%6_core_table * 2^(floor(QP/6))
+  uint32_t shift = Qp/6;
+  uint16_t* p_Qp_core_table = QP_core_table[Qp%6];
+  uint32_t i = 16;
+
+  while(i--)
+  {
+    *out++ = (((int32_t)(*in++))*((int32_t)*p_Qp_core_table++))<<shift;
+  }
+}
+
+void p264_2x2_chromaDC_scale(int16_t* in, int16_t* out, uint32_t Qp)
+// validate for several Qp on one value block
+{
+  // in and out could be the same
+  // - 2x2 chroma DC block     -> use Coeff*QP%6_core_table[0] / 2                  (Qp<6)
+  //                           -> use Coeff*QP%6_core_table[0] * 2^(floor(QP/6)-1)  (Qp>=6)
+  uint32_t shift = Qp/6-1;
+  uint32_t scale = QP_core_table[Qp%6][0];
+  if (Qp < 6)
+  {
+    *out++ = (((int32_t)(*in++))*scale)>>1;
+    *out++ = (((int32_t)(*in++))*scale)>>1;
+    *out++ = (((int32_t)(*in++))*scale)>>1;
+    *out++ = (((int32_t)(*in++))*scale)>>1;
+  }
+  else
+  {
+    *out++ = (((int32_t)(*in++))*scale)<<shift;
+    *out++ = (((int32_t)(*in++))*scale)<<shift;
+    *out++ = (((int32_t)(*in++))*scale)<<shift;
+    *out++ = (((int32_t)(*in++))*scale)<<shift;
+  }
+}
+
+void p264_4x4_lumaDC_scale(int16_t* in, int16_t* out, uint32_t Qp)
+{
+  // - 4x4 luma DC block       -> use Coeff*QP%6_core_table[0] * 2^(floor(QP/6)-2)                     (Qp>=12)
+  //                           -> use [Coeff*QP%6_core_table[0] + 2^(1-floor(QP/6)] >> (2-floor(QP/6)) (Qp<12)
+  uint32_t shift;
+  int32_t round;
+  uint32_t scale = QP_core_table[Qp%6][0];
+  uint32_t i = 16;
+  if (Qp < 12)
+  {
+	//  [QP%6_core_table[0] + 2^(1-floor(QP/6)] >> (2-floor(QP/6))
+    shift = 2-Qp/6;
+    round = 2<<(1-Qp/6);
+    while(i--)
+    {
+	  *out++ = (((int32_t)(*in++))*scale + round )>>shift;
+    }
+  }
+  else
+  {
+    shift = Qp/6-2;
+    while(i--)
+    {
+    	*out++ = (((int32_t)(*in++))*scale)<<shift;
+    }
+  }
+}
+