Fixing Issue 218

Taking care of the case when the raw waiting times vector from
NetEQ is zero length.

Also adding a new unittest to cover this case.

BUG=http://code.google.com/p/webrtc/issues/detail?id=218
TEST=AcmNetEqTest.TestZeroLengthWaitingTimesVector

Review URL: http://webrtc-codereview.appspot.com/349003

git-svn-id: http://webrtc.googlecode.com/svn/trunk@1370 4adac7df-926f-26a2-2b94-8c16560cd09d

src/modules/audio_coding/main/source/acm_neteq.cc

@@ -482,22 +482,31 @@ ACMNetEQ::NetworkStatistics(
         sort(waiting_times_vec.begin(), waiting_times_vec.end());
         size_t size = waiting_times_vec.size();
         assert(size == static_cast<size_t>(waiting_times_len));
-        if (size % 2 == 0)
+        if (size == 0)
         {
-            statistics->medianWaitingTimeMs =
+            statistics->meanWaitingTimeMs = -1;
-                (waiting_times_vec[size / 2 - 1] +
+            statistics->medianWaitingTimeMs = -1;
-                    waiting_times_vec[size / 2]) / 2;
+            statistics->maxWaitingTimeMs = -1;
         }
         else
         {
-            statistics->medianWaitingTimeMs = waiting_times_vec[size / 2];
+            if (size % 2 == 0)
+            {
+                statistics->medianWaitingTimeMs =
+                    (waiting_times_vec[size / 2 - 1] +
+                        waiting_times_vec[size / 2]) / 2;
+            }
+            else
+            {
+                statistics->medianWaitingTimeMs = waiting_times_vec[size / 2];
+            }
+            statistics->maxWaitingTimeMs = waiting_times_vec.back();
+            double sum = 0;
+            for (size_t i = 0; i < size; ++i) {
+              sum += waiting_times_vec[i];
+            }
+            statistics->meanWaitingTimeMs = static_cast<int>(sum / size);
         }
-        statistics->maxWaitingTimeMs = waiting_times_vec.back();
-        double sum = 0;
-        for (size_t i = 0; i < size; ++i) {
-          sum += waiting_times_vec[i];
-        }
-        statistics->meanWaitingTimeMs = static_cast<int>(sum / size);
     }
     else
     {

src/modules/audio_coding/main/source/acm_neteq_unittest.cc

@@ -111,10 +111,35 @@ TEST_F(AcmNetEqTest, NetworkStatistics) {
   EXPECT_EQ(0, stats.currentExpandRate);
   EXPECT_EQ(0, stats.currentPreemptiveRate);
   EXPECT_EQ(0, stats.currentAccelerateRate);
-  EXPECT_EQ(-916, stats.clockDriftPPM);
+  EXPECT_EQ(-916, stats.clockDriftPPM);  // Initial value is slightly off.
   EXPECT_EQ(300, stats.maxWaitingTimeMs);
   EXPECT_EQ(159, stats.meanWaitingTimeMs);
   EXPECT_EQ(160, stats.medianWaitingTimeMs);
 }
 
+TEST_F(AcmNetEqTest, TestZeroLengthWaitingTimesVector) {
+  // Insert one packet.
+  const int kSamples = 10 * 16;
+  const int kPayloadBytes = kSamples * 2;
+  int i = 0;
+  InsertZeroPacket(i, i * kSamples, kPcm16WbPayloadType, 0x1234, false,
+                   kPayloadBytes);
+  // Do not pull out any data.
+
+  ACMNetworkStatistics stats;
+  ASSERT_EQ(0, neteq_.NetworkStatistics(&stats));
+  EXPECT_EQ(0, stats.currentBufferSize);
+  EXPECT_EQ(0, stats.preferredBufferSize);
+  EXPECT_FALSE(stats.jitterPeaksFound);
+  EXPECT_EQ(0, stats.currentPacketLossRate);
+  EXPECT_EQ(0, stats.currentDiscardRate);
+  EXPECT_EQ(0, stats.currentExpandRate);
+  EXPECT_EQ(0, stats.currentPreemptiveRate);
+  EXPECT_EQ(0, stats.currentAccelerateRate);
+  EXPECT_EQ(-916, stats.clockDriftPPM);  // Initial value is slightly off.
+  EXPECT_EQ(-1, stats.maxWaitingTimeMs);
+  EXPECT_EQ(-1, stats.meanWaitingTimeMs);
+  EXPECT_EQ(-1, stats.medianWaitingTimeMs);
+}
+
 }  // namespace

src/modules/audio_coding/neteq/automode.c

@@ -729,7 +729,7 @@ int32_t WebRtcNetEQ_AverageIAT(const AutomodeInst_t *inst) {
   /* Subtract the nominal inter-arrival time 1 = 2^24 in Q24. */
   sum_q24 -= (1 << 24);
   /*
-   * Multiply with 1000000 / 2^24 = 15625 / 2^18 to get the average.
+   * Multiply with 1000000 / 2^24 = 15625 / 2^18 to get in parts-per-million.
    * Shift 7 to Q17 first, then multiply with 15625 and shift another 11.
    */
   return ((sum_q24 >> 7) * 15625) >> 11;