configure: add --enable-coefficient-range-checking

This commit adds a configure time option used to enable strict error
checking in decoder to make sure intermediate stage cofficients of
inverse transforms are within valid range of signed 16 bit integer.

For valid VP9 input streams, intermediate stage coefficients should
always stay within the range of a signed 16 bit integer. Coefficients
can go out of this range for invalid/corrupt VP9 streams. However,
strictly checking this range for every intermediate coefficient can
be a burden for decoder, therefore such validation is only enabled
with configure option --enable-coefficient-range-checking.

Change-Id: I47d47c8c4e48a922c3d223ca59064f51b3f0f5ed

diff --git a/configure b/configure
index 789e6c30a3c476bb6a7f3985421f747cf29438c1..92ca061b91267e6152ea437d87fc260ac10147a6 100755 (executable)
--- a/configure
+++ b/configure
@@ -46,6 +46,9 @@ Advanced options:
   ${toggle_realtime_only}         enable this option while building for real-time encoding
   ${toggle_onthefly_bitpacking}   enable on-the-fly bitpacking in real-time encoding
   ${toggle_error_concealment}     enable this option to get a decoder which is able to conceal losses
+  ${toggle_coefficient_range_checking}
+                                  enable decoder to check if intermediate
+                                  transform coefficients are in valid range
   ${toggle_runtime_cpu_detect}    runtime cpu detection
   ${toggle_shared}                shared library support
   ${toggle_static}                static library support
@@ -327,6 +330,7 @@ CONFIG_LIST="
     encode_perf_tests
     multi_res_encoding
     temporal_denoising
+    coefficient_range_checking
     experimental
     size_limit
     ${EXPERIMENT_LIST}
@@ -384,6 +388,7 @@ CMDLINE_SELECT="
     encode_perf_tests
     multi_res_encoding
     temporal_denoising
+    coefficient_range_checking
     experimental
 "
 

diff --git a/vp9/common/vp9_idct.h b/vp9/common/vp9_idct.h
index 3253bcbf4a6cee9c923ae332e84dad706c8fefb8..7f595e1cca205b7793b67cbfb859198b4117cc2a 100644 (file)
--- a/vp9/common/vp9_idct.h
+++ b/vp9/common/vp9_idct.h
@@ -81,6 +81,16 @@ static const int sinpi_4_9 = 15212;
 
 static INLINE int dct_const_round_shift(int input) {
   int rv = ROUND_POWER_OF_TWO(input, DCT_CONST_BITS);
+#if CONFIG_COEFFICIENT_RANGE_CHECKING
+  // For valid VP9 input streams, intermediate stage coefficients should always
+  // stay within the range of a signed 16 bit integer. Coefficients can go out
+  // of this range for invalid/corrupt VP9 streams. However, strictly checking
+  // this range for every intermediate coefficient can burdensome for a decoder,
+  // therefore the following assertion is only enabled when configured with
+  // --enable-coefficient-range-checking.
+  assert(INT16_MIN <= rv);
+  assert(rv <= INT16_MAX);
+#endif
   return (int16_t)rv;
 }