Re: Re: Pixel format suggestions for MCF

<[email protected]> wrote in message news:[email protected]...
| On Wed, Oct 30, 2002 at 05:33:22PM +0100, ChristianHJW wrote:
| > Alex, it was planned to have the possibility to store Aspect Ratios for
each
| > video stream in the MCF header, irrespective of what video codec is
used.
|
| Right.  This is a Good Thing(tm)..
|
| > This is only possible of course if MCF parser will call video renderer
| > directly ( talking in Dshow terms, dont know about Linux, but should
well be
| > feasible also i guess ) to tell it the width and height. If MCF parser
| > connects to an existing Dshow filter for the video codec there is no way
to
| > influence AR as i understand it ...
|
| No, that's not true.  libmcf should make aspect ratio information
available to
| the application reading the MCF file, but it's not libmcf's job to
actually do
| anything with that information.  It is up to the application to ensure
that
| either the rendering component performs appropriate aspect ratio
conversion, or
| that the video stream is fed through a resizing filter with appropriate
| parameters before being sent to the renderer.  Only the app/renderer can
know
| the correct interpretation of AR data because only it knows how the video
data
| is being rendered, and what the native AR of the renderer will be.  Many
video
| playing applications will also want to use postprocessing filters on the
output
| before scaling for aspect ratio, and some applications (such as
transcoding
| apps) will not want to adjust the image data for AR at all, period.  This
| should be something left up to the app, not something done in libmcf.
| -alex


Good point. AR correction would not work in normal WMP 6.4/7/8/9 then, as
well as in any other basic Dshow based player, but this is maybe accetable ?
If players with specific MCF support like TCMP, gst-player or mplayer (
hopefully )  can read/use the information, as well as hardware devices ( no
discussing about the probability this will ever happen please ) then its
maybe good enough ?

Whats your opinion on this guys ? Ludovic ? anybody ?

Christian






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