Add a NeededFrequency() method to the AudioMixer::Source interface.

Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org

Committed: https://crrev.com/051f678808d03fb2e68fe2a084b1deeb326c71bf
Cr-Commit-Position: refs/heads/master@{#14839}

[aleloi, 2016-10-31 09:25:54]

Description was changed from

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
==========

to

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
TBR=solenberg@webrtc.org
==========

[aleloi, 2016-10-31 09:25:55]

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

[aleloi, 2016-10-31 09:31:38]

Hi! Can you take a look? It's a short CL related to a resampling issue (details
communicated offline) in the AudioMixer.

https://codereview.webrtc.org/2448113009/diff/1/webrtc/api/audio/audio_mixer.h
File webrtc/api/audio/audio_mixer.h (right):

https://codereview.webrtc.org/2448113009/diff/1/webrtc/api/audio/audio_mixer....
webrtc/api/audio/audio_mixer.h:45: virtual int Ssrc() = 0;
Unrelated: I think Ssrc should be const as well. The gain from allowing to use
the source in a const setting is greater than the loss of not allowing a
state-changing implementation. And how could it even be that a source needs to
modify state to produce an Ssrc?

[kwiberg-webrtc, 2016-10-31 09:43:20]

lgtm, but I'm not so happy with the name. It would have made sense for a sink
(although I'd still have preferred "RequiredSampleRate" for that case), but for
a source it was confusing. At least for me...

https://codereview.webrtc.org/2448113009/diff/1/webrtc/api/audio/audio_mixer.h
File webrtc/api/audio/audio_mixer.h (right):

https://codereview.webrtc.org/2448113009/diff/1/webrtc/api/audio/audio_mixer....
webrtc/api/audio/audio_mixer.h:45: virtual int Ssrc() = 0;
On 2016/10/31 09:31:38, aleloi wrote:
> Unrelated: I think Ssrc should be const as well. The gain from allowing to use
> the source in a const setting is greater than the loss of not allowing a
> state-changing implementation. And how could it even be that a source needs to
> modify state to produce an Ssrc?

Sounds good to me.

https://codereview.webrtc.org/2448113009/diff/1/webrtc/api/audio/audio_mixer....
webrtc/api/audio/audio_mixer.h:49: virtual int NeededFrequency() const = 0;
So this is the native sample rate of the source? May I suggest
"NativeSampleRate" or "PreferredSampleRate" in that case?

[aleloi, 2016-10-31 10:23:16]

Description was changed from

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
TBR=solenberg@webrtc.org
==========

to

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org
==========

[aleloi, 2016-10-31 10:25:26]

The CQ bit was checked by aleloi@webrtc.org

[aleloi, 2016-10-31 10:25:27]

The patchset sent to the CQ was uploaded after l-g-t-m from kwiberg@webrtc.org
Link to the patchset: https://codereview.webrtc.org/2448113009/#ps20001 (title:
"Changed name to PreferredSampleRate and made Ssrc const.")

[commit-bot: I haz the power, 2016-10-31 10:25:29]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-10-31 10:26:42]

Description was changed from

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org
==========

to

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org
==========

[commit-bot: I haz the power, 2016-10-31 10:26:43]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-31 10:26:51]

Description was changed from

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org
==========

to

==========
Add a NeededFrequency() method to the AudioMixer::Source interface.

This change will allow for a audio source to report its sampling rate
to the audio mixer. It is needed in order to mix at a lower sampling
rate. Mixing at a lower sampling rate can in many cases lead to big
efficiency improvements, as reported by experiments.

The code affected is all implementations of the Source interface:
AudioReceiveStream and a mock class. The AudioReceiveStream now
queries its underlying voe::Channel object for the needed frequency.

Note that the changes to the mixing algorithm are done in a later CL.

BUG=webrtc:6346
NOTRY=True
TBR=solenberg@webrtc.org

Committed: https://crrev.com/051f678808d03fb2e68fe2a084b1deeb326c71bf
Cr-Commit-Position: refs/heads/master@{#14839}
==========

[commit-bot: I haz the power, 2016-10-31 10:26:54]

Patchset 2 (id:??) landed as
https://crrev.com/051f678808d03fb2e68fe2a084b1deeb326c71bf
Cr-Commit-Position: refs/heads/master@{#14839}