WebRTC on Android performance/battery

[Vladimir Ralev]

I am curious since there is probably no hardware-accelerated VP8 encoding on any phones, how is VP8 encoding even viable on small android devices?

Are the codecs implemented in Java, asm, C?

Are the parameters of the encoding somewhat bad in order not to overuse the CPU (in terms of video resolution, codec features enabled and so on)?

What would be the expected battery life? On my Galaxy I can stream justin tv for about 1-2 hours and this is just decoding. If you add encoding I imagine it will be much worse?

[Punyabrata Ray]

I am curious since there is probably no hardware-accelerated VP8 encoding on any phones,

[ray] This should be changing in 2013 as you will begin to see VP8 encode/decode chipsets in the market. Currently the Nexus 10 tablet has an onboard VP8 decoder. Google also freely provides the VP8 RTL to any semiconductor company that wants it:

http://www.webmproject.org/hardware/ 

how is VP8 encoding even viable on small android devices?

[ray] While HW acceleration is desired for reasons as you mentioned longer battery life and potentially encoding at higher resolutions, it is absolutely possible to run VP8 encode/decode purely in software on current mobile devices. 

 

Are the codecs implemented in Java, asm, C?

[ray] VP8 source: http://code.google.com/p/webm/source/browse/?repo=libvpx#git%2Fvp8%253Fstate%253Dclosed 

Are the parameters of the encoding somewhat bad in order not to overuse the CPU (in terms of video resolution, codec features enabled and so on)?

[ray]Yes, there are parameters within VP8 that can tradeoff complexity for quality but in the scope of the WebRTC project, this is something the developers will not need to worry about. When we shift our focus to mobile platforms, we will ensure to have balanced these trade-offs.