Originally Posted by Kronblom  Now, if i have used a PAL miniDV camera to record the material:
1. Is the material recorded progressively or interlaced?
2. If the material is shot in 50 fps, what should i render it to since 50 fps isnīt a selectable frame rate in render settings?
3. If itīs progressive what settings do i choose in Sony vegas?
4. If itīs interlaced what settings do i choose in Sony Vegas?
5. Is there a way of fixing it without sacrificing quality?
...
Or could it perhaps have to do with downsizing ? Thereīs alot of talk about the need for resizing to solve these kinds of issues but no real reasons why resizing solves interlacing-issues and no directions as to how this resizing should take place. |
My understanding...(and it's no more than that so I really hope I don't muddy the water by posting innacuracies)
1. Is the material recorded progressively or interlaced?
Interlaced
2. If the material is shot in 50 fps, what should i render it to since 50 fps isnīt a selectable frame rate in render settings?
It is shot in 50 FIELDs per second not FRAMES per second. It is 50i where the i is for interlaced. You are already aware that this means the odd numbered lines making up the image (one field) are shot then the even number of lines are shot (another field) and thus to make up a whole picture you need to combine the odd and the even. However, given that these FIELDS are shot 1/50th second apart, where there is movement the resultant image will have the comb effect. This is absolutely fine when played back on a TV which alternately plays back the even and odd lines.
This can be easily demonstrated by capturing from MiniDV and loading onto the timeline. Assuming project properties are set to PAL (and your footage was PAL) Vegas displays 25 FRAMES per second on the timeline. One FRAME on the timeline comprises one even FIELD and one odd FIELD. Zoom in on the preview and you can clearly see this.
If you simply take this and output a PAL MPEG2 DVD it will look EXACTLY the same on a TV as direct from the camera.
(I'm not sure of the numbers in the following, but I think the principle is correct)..
The problem occurs when you zoom or crop.
Your interlaced 1/25th sec frame is made up of 625 (that's the number I'm unsure of) lines.
If you zoom in a bit, your now looking at an image of say 500 lines. But this image needs to be re-split into 625 lines for display on a device expecting interlaced output. Obviously the odd/even lines don't match any more.
The way around this is to de-interlace the image first so that instead of each frame being made up of two fields 1/50th sec apart, you get a single frame (progressive).
This frame has to be calculated based on the original two fields and this is where your compromise takes place - and hence your loss in quality. There is no panacea here, you just have to try different methods of deinterlacing to get the best quality.
One method is to deinterlace & render (you can use programs other than Vegas) those sections you want to crop before pulling them into your project.
I feel for you - I had similar problems and I now try to avoid any sort of zooming.
The strange thing is, since I've become aware of the problem and gone some way to understanding it, I haven't really suffered it.
I hope others with a better undertsanding will elaborate and correct.