Re: [rtcweb] On video codec for rtcweb

[Roman Shpount <[e-mail]>]

On Fri, Mar 23, 2012 at 3:00 PM, Basil Mohamed Gohar <
[e-mail]> wrote:

> On 03/23/2012 12:48 PM, Roman Shpount wrote:
> > On Fri, Mar 23, 2012 at 8:34 AM, Timothy B. Terriberry
> > <[e-mail] <mailto:[e-mail]>> wrote:
> >
> >     With a direct browser-to-browser connection, there is nothing
> >     sitting between them to do the transcoding. In the DTLS-SRTP case
> >     with identity verification, which I think a number of people here
> >     view as highly important, you are in fact _guaranteeing_ that
> >     nothing but the browser can encode or decode the video.
> >
> >
> > This is not technically correct. You can still build a system that
> > implements a media proxy that does nothing but handling ICE,
> > encryption, and identity verification without ever transcoding the
> > content. The cost of re-encrypting the media is low (ie single E5 Xeon
> > CPU can probably do about 10GB/s), but the cost of transcoding video,
> > or even audio is huge in comparison. Because of this, supporting a
> > comprehensive set of codecs is highly desirable.
> While perhaps technically desirable for those already knee-deep in the
> existing telecommunications, it will serve to lock-out any WebRTC
> implementations that either choose to or cannot implement an encumbered
> format, such as free/open source software developers and companies.  As
> of right now, there *are* no official complete WebRTC implementations to
> inconvenience by choosing a mandatory-to-implement codec.  It would be
> only an inconvenience to existing infrastructure, but because of the
> free and open nature of the proposed format, adding support for it in
> software would be a minimal effort, especially as it would standardized.
>
> The reference implementation of VP8 (libvpx) is also licensed in such as
> a way as to be equally available to all types of software.
>
>
I am not arguing for making H.264 a base codec. I would actually prefer
VP8. All I was saying that despite lack of interoperability on encryption,
ICE, and identity, there are still significant benefits of supporting the
same codecs when communicating with legacy equipment, since re-encryption
and media proxy can be handled separately and using much less resources
then transcoding.
_____________
Roman Shpount