Major AEC3 render pipeline changes

webrtc/modules/audio_processing/aec3/aec3_common.h

Index: webrtc/modules/audio_processing/aec3/aec3_common.h
diff --git a/webrtc/modules/audio_processing/aec3/aec3_common.h b/webrtc/modules/audio_processing/aec3/aec3_common.h
index 1d4a9feba1e8fd67762a4921e2663b55353e1e56..f5a2626d0b7d74b19ce32f24a5f802fc76a0bd74 100644
--- a/webrtc/modules/audio_processing/aec3/aec3_common.h
+++ b/webrtc/modules/audio_processing/aec3/aec3_common.h
@@ -31,6 +31,8 @@ constexpr int kMetricsComputationBlocks = 9;
 constexpr int kMetricsCollectionBlocks =
     kMetricsReportingIntervalBlocks - kMetricsComputationBlocks;
 
+constexpr int kAdaptiveFilterLength = 12;

[peah-webrtc, 2017/03/30 05:36:55]

The adaptive filter lengths has now been fixed into a constant (which is how it
is actually used). This change will take effect in the next CL, and the code
will be further refactored accordingly after that.

+
 constexpr size_t kFftLengthBy2 = 64;
 constexpr size_t kFftLengthBy2Plus1 = kFftLengthBy2 + 1;
 constexpr size_t kFftLengthBy2Minus1 = kFftLengthBy2 - 1;
@@ -43,6 +45,22 @@ constexpr size_t kBlockSize = kFftLengthBy2;
 constexpr size_t kExtendedBlockSize = 2 * kFftLengthBy2;
 constexpr size_t kSubBlockSize = 16;
 
+constexpr size_t kNumMatchedFilters = 4;

[peah-webrtc, 2017/03/30 05:36:55]

The matched filter number, as well as the alignment of that, has now as well
been set as a constant. That makes sense, as it is how it is actually used.
Apart from that, however, it was a necessity as the lengths of the render
buffers are now are no longer fully independent

+constexpr size_t kMatchedFilterWindowSizeSubBlocks = 32;
+constexpr size_t kMatchedFilterAlignmentShiftSizeSubBlocks =
+    kMatchedFilterWindowSizeSubBlocks * 3 / 4;
+constexpr size_t kDownsampledRenderBufferSize =
+    kSubBlockSize *
+    (kMatchedFilterAlignmentShiftSizeSubBlocks * kNumMatchedFilters +
+     kMatchedFilterWindowSizeSubBlocks +
+     1);
+
+constexpr size_t kRenderDelayBufferSize =
+    (3 * kDownsampledRenderBufferSize) / (4 * kSubBlockSize);
+
+constexpr size_t kMaxApiCallsJitterBlocks = 9;
+constexpr size_t kRenderTransferQueueSize = kMaxApiCallsJitterBlocks / 2;
+
 constexpr size_t NumBandsForRate(int sample_rate_hz) {
   return static_cast<size_t>(sample_rate_hz == 8000 ? 1
                                                     : sample_rate_hz / 16000);