shithub: libvpx

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ref: 49b4a274a0e30d90496081340a80846a1c371eaf
parent: 2c1cdf69b6ebece5052c7a1b20e017925836bd96
author: Jingning Han <[email protected]>
date: Thu May 29 08:50:54 EDT 2014 

Add overflow check unit test for 16x16 inverse DCT/ADST transform

This commit applies quantization process with coarse quantization
step size to the forward transform coefficients and tests all the
inverse 16x16 DCT and ADST implementation versions with the
dequantized coefficients as input, to verify that the outcomes
match the prototype.

Change-Id: I68034a6126b45192c87d8c642155290e89bff8fa


--- a/test/dct16x16_test.cc
+++ b/test/dct16x16_test.cc
@@ -272,10 +272,18 @@
   vp9_fdct16x16_c(in, out, stride);
 }
 
+void idct16x16_ref(const int16_t *in, uint8_t *dest, int stride, int tx_type) {
+  vp9_idct16x16_256_add_c(in, dest, stride);
+}
+
 void fht16x16_ref(const int16_t *in, int16_t *out, int stride, int tx_type) {
   vp9_fht16x16_c(in, out, stride, tx_type);
 }
 
+void iht16x16_ref(const int16_t *in, uint8_t *dest, int stride, int tx_type) {
+  vp9_iht16x16_256_add_c(in, dest, stride, tx_type);
+}
+
 class Trans16x16TestBase {
  public:
   virtual ~Trans16x16TestBase() {}
@@ -378,6 +386,47 @@
     }
   }
 
+  void RunQuantCheck(int dc_thred, int ac_thred) {
+    ACMRandom rnd(ACMRandom::DeterministicSeed());
+    const int count_test_block = 1000;
+    DECLARE_ALIGNED_ARRAY(16, int16_t, input_block, kNumCoeffs);
+    DECLARE_ALIGNED_ARRAY(16, int16_t, input_extreme_block, kNumCoeffs);
+    DECLARE_ALIGNED_ARRAY(16, int16_t, output_ref_block, kNumCoeffs);
+
+    DECLARE_ALIGNED_ARRAY(16, uint8_t, dst, kNumCoeffs);
+    DECLARE_ALIGNED_ARRAY(16, uint8_t, ref, kNumCoeffs);
+
+    for (int i = 0; i < count_test_block; ++i) {
+      // Initialize a test block with input range [-255, 255].
+      for (int j = 0; j < kNumCoeffs; ++j) {
+        input_block[j] = rnd.Rand8() - rnd.Rand8();
+        input_extreme_block[j] = rnd.Rand8() % 2 ? 255 : -255;
+      }
+      if (i == 0)
+        for (int j = 0; j < kNumCoeffs; ++j)
+          input_extreme_block[j] = 255;
+      if (i == 1)
+        for (int j = 0; j < kNumCoeffs; ++j)
+          input_extreme_block[j] = -255;
+
+      fwd_txfm_ref(input_extreme_block, output_ref_block, pitch_, tx_type_);
+
+      // clear reconstructed pixel buffers
+      vpx_memset(dst, 0, kNumCoeffs * sizeof(uint8_t));
+      vpx_memset(ref, 0, kNumCoeffs * sizeof(uint8_t));
+
+      // quantization with maximum allowed step sizes
+      output_ref_block[0] = (output_ref_block[0] / dc_thred) * dc_thred;
+      for (int j = 1; j < kNumCoeffs; ++j)
+        output_ref_block[j] = (output_ref_block[j] / ac_thred) * ac_thred;
+      inv_txfm_ref(output_ref_block, ref, pitch_, tx_type_);
+      REGISTER_STATE_CHECK(RunInvTxfm(output_ref_block, dst, pitch_));
+
+      for (int j = 0; j < kNumCoeffs; ++j)
+        EXPECT_EQ(ref[j], dst[j]);
+    }
+  }
+
   void RunInvAccuracyCheck() {
     ACMRandom rnd(ACMRandom::DeterministicSeed());
     const int count_test_block = 1000;
@@ -414,6 +463,7 @@
   int pitch_;
   int tx_type_;
   fht_t fwd_txfm_ref;
+  iht_t inv_txfm_ref;
 };
 
 class Trans16x16DCT
@@ -428,6 +478,7 @@
     tx_type_  = GET_PARAM(2);
     pitch_    = 16;
     fwd_txfm_ref = fdct16x16_ref;
+    inv_txfm_ref = idct16x16_ref;
   }
   virtual void TearDown() { libvpx_test::ClearSystemState(); }
 
@@ -455,6 +506,12 @@
   RunMemCheck();
 }
 
+TEST_P(Trans16x16DCT, QuantCheck) {
+  // Use maximally allowed quantization step sizes for DC and AC
+  // coefficients respectively.
+  RunQuantCheck(1336, 1828);
+}
+
 TEST_P(Trans16x16DCT, InvAccuracyCheck) {
   RunInvAccuracyCheck();
 }
@@ -471,6 +528,7 @@
     tx_type_  = GET_PARAM(2);
     pitch_    = 16;
     fwd_txfm_ref = fht16x16_ref;
+    inv_txfm_ref = iht16x16_ref;
   }
   virtual void TearDown() { libvpx_test::ClearSystemState(); }
 
@@ -496,6 +554,12 @@
 
 TEST_P(Trans16x16HT, MemCheck) {
   RunMemCheck();
+}
+
+TEST_P(Trans16x16HT, QuantCheck) {
+  // The encoder skips any non-DC intra prediction modes,
+  // when the quantization step size goes beyond 988.
+  RunQuantCheck(549, 988);
 }
 
 using std::tr1::make_tuple;