Re: [Ekiga-list] Video resolution

[Eugen Dedu <Eugen Dedu pu-pm univ-fcomte fr>]

Bret Busby wrote:
> On Wed, 23 Dec 2009, yannick wrote:
> 
>> Date: Wed, 23 Dec 2009 11:48:42 +0100
>> From: yannick <sevmek free fr>
>> Reply-To: Ekiga mailing list <ekiga-list gnome org>
>> To: Ekiga mailing list <ekiga-list gnome org>
>> Subject: Re: [Ekiga-list] Video resolution
>>
>> Le mardi 22 décembre 2009 à 17:30 +0800, Bret Busby a écrit :
>> Hello.
>>
>> I am wondering what prospect exists, for the video resolution, and
>> thus the displayed video size on screen, to be increased?
>>
>> I have recently purchased a Logitech C300 webcam, which apparently has
>> video resolution of up to 1.3MP; 1280 x 1024, I think.
>>
>> The webcam came with access to a Logitech free videocall facility'
>> "Vid", which apparently (on this computer, anyway) allows for video
>> resolution of up to 640 x480, at 30fps.
>>
>> So, I am wondering whether any intent exists, for Ekiga to provide for
>> image resolution of 640 x 480, or, better, also, 800 x 600, or, even
>> better, also, 1280 x 1024, at 30fps.
>>
> 
>> The higher you can get with Ekiga 3.2.x is: 704x576 30fps
> 
>> (This is 4CIF, see http://en.wikipedia.org/wiki/4CIF )
> 
> Okay, now I understand; the video format used by Ekiga, is apparently
> for television screens, rather than for computers -
> ("CIF was designed to be easy to convert to PAL or NTSC standards. CIF
> defines a video sequence with a resolution of 352  288 like PAL Source
> Input Format, a framerate of 30000/1001 (roughly 29.97) frames like
> NTSC, with colour encoded using YCbCr 4:2:0."
> and
> "xCIF pixels are not square, instead having a native aspect ratio of
> ~1.222:1. On older television systems, a pixel aspect ratio of 1.2:1 was
> the standard for 525-line systems (see CCIR 601). On square-pixel
> displays (computer screens, many modern televisions) xCIF rasters should
> be rescaled horizontally by ~109% to 4:3 in order to avoid a "stretched"
> look: CIF content expanded horizontally by ~109% results in a 4:3 raster
> of 384  288 square pixels.").
> 
> I assume that the 4CIF resolution, is what used to be named something
> like High Definition television, in the 4:3 analogue television format
> (now all television screens available in sizes bigger than 14"
> diagonally, are this silly widescreen format, that makes the pictures
> look like someone heavy has sat on them).
> 
> So, is the 4CIF format available for Ekiga, and, how can a user select
> that resolution, to be used?
> 
> I could not find a means of selecting different resolutions, in the
> facilities for configuring the Ekiga interface.
> 
> Does a method or facility exist, whereby a user (one party to a call)
> selects a particular resolution, as a maximum possible resolution to be
> viewed by the user, and the user interface software or carrier software,
> then determines the lower common factor for the resolution selection
> between the parties to a call, and uses that lower common factor
> resolution, for the call, at each end involved in the call, so that, if
> one party to a call, sets the maximum possible resolution at 4CIF and
> another party sets the resolution at CIF, the CIF resolution gets used
> by the call, to optimise bandwidth usage (me sending video at 4CIF,
> isn't much use, if a receiver can view only CIF) and the call then
> progresses using the lower common factor resolution?

Hi,

You can set *your* resolution (the one you send, i.e. your local video)
in Preferences/Video.

To my understanding, a common resolution is not useful.  Your resolution
and your partner's one can be different, I have seen it.  So I think
it's not useful to negociate it.

-- 
Eugen