Herman Robak wrote: > On Fri, 24 Aug 2007 21:58:55 +0200, Derek McTavish Mounce > <[EMAIL PROTECTED]> wrote: > >> Forgot this. More of a question on what you mean exactly: >> >>> An NLE that deals >>> with TV material (not just cinematic stuff) ought to be able to >>> preserve interlacing throughout the workflow, no matter how many >>> effects or transformations you throw in. >> >> It is absolutely not possible to apply a transformation other than >> simple >> translation to interlaced video and maintain the interlacing. If you >> scale or rotate the image, you're scaling/rotating the fields which >> completely defeats the purpose of interlacing. You must deinterlace. >> There's not a program out there that can maintain proper interlacing once >> you scale, rotate, or apply fx. >> >> Perhaps though I'm misunderstanding, in which case please explain >> further. :) > > Maybe, maybe not. > > You do not have to deinterlace in the common meaning: Merging fields > into frames, thus reducing 50i to 25p. To maintain the temporal > resolution, one has to do the opposite: separate the fields, and > process them separately. They are separate images, after all. > > Here is how I think it should go: > > 1) Split out the fields, putting them after one another on the timeline. > > 2 a) Line-double or interpolate them up to full vertical resolution > or > b) Make the rendering pipeline treat the fields as very wide > non-square pixels. b) .. lets us safe memory since fields have only half the bandwidth (memory, cpu,..), but we need pixel aspect and the render pipe needs to be aware of this, it needs also be aware that bottom fields are shifted a halfline lower (important for temporal effects).
> > 3) Transform, rotate, translate, filter, whatever the fields... > > 4) Merge back the fields to frames, if/when appropriate. > > > Since field 1 and 2 are separated on the timeline, all the pixels > in the final field 1 will come from the source field 1, no matter > the deformations that have been applied. > The pixels may need stretching or interpolation to fit into their > new positions, but keeping the fields apart is just a matter of > combing them out and putting them in their correct temporal position > on the timeline. > > A capable NLE should do that. ack > > --Herman Robak > > _______________________________________________ > Cinelerra mailing list > [email protected] > https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
