Re: [rtcweb] Interlace (Re: Video resolution SHOULDs (Re: resolutions in draft-cbran-rtcweb-codec-01))

-inline
Stephen Botzko

On Wed, Nov 30, 2011 at 8:25 AM, Harald Alvestrand <harald@alvestrand.no>wrote:

> On 11/30/2011 06:18 AM, James M. Polk wrote:
>
>> At 10:56 PM 11/29/2011, Ralph Giles wrote:
>>
>>> On 29 November 2011 11:49, Harald Alvestrand <harald@alvestrand.no>
>>> wrote:
>>>
>>> > Interlace? Just Say No!
>>>
>>> Works for me. I'm an optimist.
>>>
>>
>> not meaning to open a can of worms, but what still requires interlaced
>> video? Most new things convert I to P, but less of these convert P to I.
>>
> Just hit the same conversation here in Geneva at MPEG meeting. Funny what
> you learn!
>
> Interlaced material requires quite extensive resources on the decoding end
> to do properly, and if you just ignore the interlace marker and display the
> half-frames on top of each other, the resulting display is clearly
> substandard.
> But converting is a small-but-significant cost to the broadcasters with
> stored interlaced material, and the hardware guys who already have to
> implement it for some profile see no extra cost to having that support, so
> they don't push back much against it.
>
> In contrast, WebRTC is much more greenfield, and has far less established
> interlace support than TVs.
>
> If we can push interlaced material up the food chain into those devices
> that have to deal with it because it's in the archives, and get them to do
> the I-to-P conversion, the Web will be better off.
> </rant>
>
>                      Harald
>
[SB]Interlaced encoding also adds delay, so it is not generally used for
interactive applications. So I agree that it is better to keep it out of
RTCWeb.

>
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