DecoderDatabase::IsComfortNoise: Improved efficiency.

DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
Committed: https://crrev.com/6353723b029de581b1d0393ddf49c79f34b8f37c
Cr-Commit-Position: refs/heads/master@{#12533}

[ossu, 2016-04-27 10:43:49]

Description was changed from

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
==========

to

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
==========

[ossu, 2016-04-27 10:43:49]

ossu@webrtc.org changed reviewers:
+ henrik.lundin@webrtc.org

[ossu, 2016-04-27 10:45:18]

Please take a look at this change.

[kwiberg-webrtc, 2016-04-27 12:16:33]

kwiberg@webrtc.org changed reviewers:
+ kwiberg@webrtc.org

[kwiberg-webrtc, 2016-04-27 12:16:34]

lgtm

https://codereview.webrtc.org/1923763003/diff/1/webrtc/modules/audio_coding/n...
File webrtc/modules/audio_coding/neteq/decoder_database.cc (right):

https://codereview.webrtc.org/1923763003/diff/1/webrtc/modules/audio_coding/n...
webrtc/modules/audio_coding/neteq/decoder_database.cc:176: }
Suggestion for future improvement: If we're having performance problems with a
map whose keys are 7-bit integers, replacing the balanced binary tree with a
128-element array could be a big win.

[ossu, 2016-04-27 12:36:46]

On 2016/04/27 12:16:34, kwiberg-webrtc wrote:
> lgtm
> 
>
https://codereview.webrtc.org/1923763003/diff/1/webrtc/modules/audio_coding/n...
> File webrtc/modules/audio_coding/neteq/decoder_database.cc (right):
> 
>
https://codereview.webrtc.org/1923763003/diff/1/webrtc/modules/audio_coding/n...
> webrtc/modules/audio_coding/neteq/decoder_database.cc:176: }
> Suggestion for future improvement: If we're having performance problems with a
> map whose keys are 7-bit integers, replacing the balanced binary tree with a
> 128-element array could be a big win.

It's not really as bad as it seems here - the path that got a bit more expensive
is very heavily tested in the perf-test that highlighted this.
An array could probably solve this a bit quicker - either a straight mapping or
a sorted std::vector. Doing a binary, or even linear search over
eight or-so items (which is probably on the order of number of codecs actually
registered in a DecoderDatabase at any time) is super-quick thanks to locality.

That said, I wouldn't be surprised if the usage of IsComfortNoise, IsRed and
IsDtmf here will go away once we've externalized codec implementations.

[hlundin-webrtc, 2016-04-27 14:38:53]

lgtm

[ossu, 2016-04-27 14:41:58]

The CQ bit was checked by ossu@webrtc.org

[commit-bot: I haz the power, 2016-04-27 14:42:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1923763003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1923763003/1

[commit-bot: I haz the power, 2016-04-27 14:43:41]

Description was changed from

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
==========

to

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
==========

[commit-bot: I haz the power, 2016-04-27 14:43:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-27 14:43:50]

Description was changed from

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765
==========

to

==========
DecoderDatabase::IsComfortNoise: Improved efficiency.

Changed DecoderDatabase::IsComfortNoise to do one, rather than four,
lookups of the rtp payload type. IsComfortNoise is called more frequently
since CNG was changed to not be an AudioDecoder.

BUG=606765

Committed: https://crrev.com/6353723b029de581b1d0393ddf49c79f34b8f37c
Cr-Commit-Position: refs/heads/master@{#12533}
==========

[commit-bot: I haz the power, 2016-04-27 14:43:51]

Patchset 1 (id:??) landed as
https://crrev.com/6353723b029de581b1d0393ddf49c79f34b8f37c
Cr-Commit-Position: refs/heads/master@{#12533}