Re: Some ideas on SVC support in WebRTC 1.0 (Take 2)

On 09/07/2018 13:51, Harald Alvestrand wrote:
> On 07/04/2018 01:59 AM, Bernard Aboba wrote:
>>
>> [BA] If the desire is to make things as simple as possible, could we 
>> do something like this?
>>
>>
>> var encodings = [
>>   {
>>     rid: "L0",
>>     temporalLayers: 2,
>>
>> spatialLayers: 3
>>
>>  }
>>
>>
> I think this would be unwise.
>
> There are 2 parameters - temporal scaling and spatial scaling. Calling 
> a layer "temporal" or "spatial" implies that only one of these 
> parameters varies from its base layer; it should (I think) be quite 
> common to vary both.
>
I am not sure if I understand your concern, could you elaborate it a bit 
more please? As I understand the proposal, the encoding attributes 
defines the number of temporal and spatial layers that it will contain 
(same as it is done now with the chrome field trial to enable SVC for 
VP9). In this case this will create a layer structure withing the the 
encoding that would be sl0tl0, sl0tl1, sl0tl2, sl1tl0, sl1tl1, sl1tl2, 
sl2tl0, sl2tl1, sl2tl2, and the encoding parameters for each layer 
(downscale, bitrate, etc) would be decided by the browser based on the 
encoding attributes.

Best regards
Sergio