commit 8e56521143f2bd481710ea7508d5cdd3a8b6d59c
author peah <peah@webrtc.org> Mon Sep 12 11:49:45 2016
committer Commit bot <commit-bot@chromium.org> Mon Sep 12 11:49:50 2016
tree 81b81e59172d0563384de4a7002b0567b6804474
parent a64a2fbf6d92d18e77f813212905bb5eb89799b5

The output signal of the AEC needs to be buffered as the
internal block size of the AEC differ from the frame
size in the AEC output.

Before this CL, this buffering was done using ringbuffers
as well as secondary internal AEC buffers that were stored
on the state. The internal buffers were redundant, and the
ringbuffers were so short that the benefit of using
ringbuffers were lost.

This CL addresses the above issues by replacing the
ringbuffers by linear buffers. This has the main advantage
of cleaner code but it should significantly less
computational complex.

Furthermore, as the complexity of the function where the
conversion to external and internal AEC frame sizes is done
increased significantly with the changes in this CL, the
CL also include refactoring the near-end buffer handling
to increase readability and reduce code repetition.

After the changes in this CL it is very clear that the
former buffering of the output was incorrectly done for
the first frames. This CL corrects that but in doing that
it breaks the bitexactness with the former code.
The bitexactness is, however, only broken for the first
1000 samples and it has been verified that for a test suite
the CL maintains bitexactness in the AEC output
after the first 1000 samples.

This CL is chained to the CL https://codereview.webrtc.org/2311833002/ and will be
followed by more CLs that refactor the other buffers
inside the AEC.

BUG=webrtc:5298, webrtc:6018

Review-Url: https://codereview.webrtc.org/2321483002
Cr-Commit-Position: refs/heads/master@{#14184}