1050199 - [EME] Support audio sample rate and number of channels changing in decoded samples

Status: RESOLVED FIXED

(Core :: Audio/Video, defect)

Description

[Chris Pearce [:cpearce (Not reading bugmail)]]

I realized we need to be able to support the GMP giving us back something other than what we ask for. This may happen if we send an HE-AAC stream with implicitly signaled SBR/PS, where if the decoder supports those it can give us more samples/channels back. The CDM/GMP may also wish to downsample for DRM purposes.

So, we need to change the GMPAudioSamples/GMPAudioDecoder GMP-API header file to allow this.

I assume this won't affect OpenH264.

Comment 1

[Chris Pearce [:cpearce (Not reading bugmail)]]

Attachment: Patch: add Rate and Channels fields to GMPAudioSamples

Add Rate and Channels fields to GMPAudioSamples, and hook it up to IPC.

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Comment on attachment 8469195 [details] [diff] [review]
Patch: add Rate and Channels fields to GMPAudioSamples

Review of attachment 8469195 [details] [diff] [review]:
-----------------------------------------------------------------

::: content/media/fmp4/eme/EMEAACDecoder.cpp
@@ +138,5 @@
> +    mCallback->Error();
> +    return;
> +  }
> +
> +  size_t numFrames = aPCM.Length() / aChannels;

consider an assert on length%channels != 0?

::: content/media/gmp/GMPAudioDecoderParent.cpp
@@ +199,5 @@
>    if (!mCallback) {
>      return false;
>    }
>  
> +  mCallback->Decoded(aDecoded.mData(),  

spaces

::: content/media/gmp/GMPAudioDecoderProxy.h
@@ +14,5 @@
>  
>  class GMPAudioDecoderProxyCallback : public GMPCallbackBase {
>  public:
>    virtual ~GMPAudioDecoderProxyCallback() {}
> +  virtual void Decoded(const nsTArray<int16_t>& aPCM,

do we want to note here as well that channel/rate can change from one callack to another?

Comment 3

[Chris Pearce [:cpearce (Not reading bugmail)]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3c2b12761044

Comment 4

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/3c2b12761044

Comment 5

[Chris Pearce [:cpearce (Not reading bugmail)]]

Mass update firefox-status to track EME uplift.