shithub: libvpx

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[BITSTREAM]Fix the scaling calculation

For very large size video image, the scaling calculation may need use
value beyond the range of int. This commit upgrade the value to 64bit
to make sure the calculation do not wrap around INT_MAX.

The change corrected the decoder behavior.

The bug affects only very large resolution video because the scaling
calculation was sufficient for image size smaller than 2^13.

This resolves issue:
https://code.google.com/p/webm/issues/detail?id=750

Change-Id: I2d2ed303ca6482f31f819f3c07d6d3e98ef3adc5

--- a/test/test-data.sha1

+++ b/test/test-data.sha1

@@ -589,3 +589,5 @@

 92a756469fa438220524e7fa6ac1d38c89514d17  vp90-2-12-droppable_2.ivf.md5

 c21e97e4ba486520118d78b01a5cb6e6dc33e190  vp90-2-12-droppable_3.ivf

 601abc9e4176c70f82ac0381365e9b151fdd24cd  vp90-2-12-droppable_3.ivf.md5

+61c640dad23cd4f7ad811b867e7b7e3521f4e3ba  vp90-2-13-largescaling.webm

+bca1b02eebdb088fa3f389fe0e7571e75a71f523  vp90-2-13-largescaling.webm.md5

--- a/test/test.mk

+++ b/test/test.mk

@@ -694,6 +694,8 @@

 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp90-2-12-droppable_2.ivf.md5

 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp90-2-12-droppable_3.ivf

 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp90-2-12-droppable_3.ivf.md5

+LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp90-2-13-largescaling.webm

+LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp90-2-13-largescaling.webm.md5

 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp91-2-04-yv444.webm

 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += vp91-2-04-yv444.webm.md5

--- a/test/test_vectors.cc

+++ b/test/test_vectors.cc

@@ -164,7 +164,7 @@

   "vp90-2-11-size-351x287.webm", "vp90-2-11-size-351x288.webm",

   "vp90-2-11-size-352x287.webm", "vp90-2-12-droppable_1.ivf",

   "vp90-2-12-droppable_2.ivf", "vp90-2-12-droppable_3.ivf",

-  "vp91-2-04-yv444.webm"

+  "vp90-2-13-largescaling.webm", "vp91-2-04-yv444.webm"

 };

 const int kNumVP9TestVectors = NELEMENTS(kVP9TestVectors);

 #endif  // CONFIG_VP9_DECODER

--- a/vp9/common/vp9_scale.c

+++ b/vp9/common/vp9_scale.c

@@ -13,11 +13,11 @@

 #include "vp9/common/vp9_scale.h"

 static INLINE int scaled_x(int val, const struct scale_factors *sf) {

-  return val * sf->x_scale_fp >> REF_SCALE_SHIFT;

+  return (int)((int64_t)val * sf->x_scale_fp >> REF_SCALE_SHIFT);

 }

 static INLINE int scaled_y(int val, const struct scale_factors *sf) {

-  return val * sf->y_scale_fp >> REF_SCALE_SHIFT;

+  return (int)((int64_t)val * sf->y_scale_fp >> REF_SCALE_SHIFT);

 }

 static int unscaled_value(int val, const struct scale_factors *sf) {