Simple interlacing questions

[John Rofrano]

If the final destination for my home videos is for TV, should the ‘deinterlacing’ method in the rendering options ALWAYS be set to “None”?

No absolutely not! If you are working with interlaced video you need to select a deinterlace method for those times when Vegas needs to deinterlace your video to process it.

Does it matter if the TV is HD?

The HD spec also requires interlaced video. (some things will never die)

Does it matter if the device playing it is a standard DVD player or a BluRay player?

Both a DVD player and Blu-ray player expect interlaced video and will tolerate progressive video under certain circumstances (e.g., DVD’s will allow progressive video only at 23.976fps but 29.970fps and 25.000fps video must be interlaced).

ALL of my video is standard definition (via Sony TRV30 cam) and some of it has been converted from old VHS tapes to digital form. Would any of the answers above be different if my source files were HD?

It depends… HD is not a single format. HD 1920x1080i is interlaced. HD 1280x720p is progressive. So the answer would change depending on which HD format you were working with.

Finally, when are the choices “interpolate” and “blend” used?

Blend should be used in most cases. It takes the two fileds and blends them together to produce a progressive frame and maintains the highest vertical resolution. It should be used with high details and low motion.

Interpolate basically throws half of the fields away and is unfortunately the only way to deal with high motion. If you have very fast moving objects in your frame and blend doesn’t do a good job of deinterlacing because the object modes too far in between the fields, then use interpolation to fix it. It should only be used with low detail and high motion because it only uses 1/2 of the vertical resolution to produce a progressive frame.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Bob Moyer]

If the final destination for my home videos is for TV, should the ‘deinterlacing’ method in the rendering options ALWAYS be set to “None”?

[No absolutely not! If you are working with interlaced video
you need to select a deinterlace method for those times
when Vegas needs to deinterlace your video to process it.

Therein lies my confusion. My SD footage is interlaced (correct?) and my TV requires interlaced video (correct?). Why wouldn’t I choose “None” as the de-interlace method?

And are you saying that I should generally choose “Blend”?

Sorry about these stupid questions, I am a very senior citizen and I don’t seem to understand this very easily.

Thanks again.

Bob

[John Rofrano]

Therein lies my confusion. My SD footage is interlaced (correct?) and my TV requires interlaced video (correct?). Why wouldn’t I choose “None” as the de-interlace method?

There are times when internally, Vegas needs to deinterlace your footage in order to process properly. It separates each field, processes it, and then places them back where they belong. If you set the deinterlace method to None, then Vegas will ignore the fact that your footage is interlaced and mess everything up as it processes an entire frame with no regard to fields.

And are you saying that I should generally choose “Blend”?

Yes, Blend is the default and should give the best results in most circumstances.

Sorry about these stupid questions, I am a very senior citizen and I don’t seem to understand this very easily.

Actually, there is nothing here that you need to understand at all. You are making it much harder on yourself than this needs to be. If you just used the defaults provided by Vegas (Blend was the default) your videos would come out perfect every time. It’s only when people start changing parameters that they don’t understand that they get themselves into trouble. 😉

When you buy a car, do you ask your car dealer what the air-to-fuel ratio is for the fuel injectors? No, because you don’t need to know this to drive the car. But I bet if you start turning the screws on the fuel injector your car wouldn’t run smoothly for long. This is what people do with Vegas. They see parameters in the Project Properties and they change them without knowing what the parameters do and then they complain that Vegas can’t make a good looking video. All you need to do is select the proper template for your project and press OK.

If you’ve done a lot of “tweaking of the unknown” I would highly recommend that you reset Vegas to it’s factory defaults and stop tweaking. You can do this by holding down the Shift key as you start Vegas. It will ask you if you want to reset and you should say Yes. This will wipe out any preference changes you have made but if you have randomly made changes, this might not be a bad thing.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Bob Moyer]

Thank you very much for your explainations. I have not ‘tweeked’ Vegas at all. I had rendered out a clip with the original defaults and I thought it looked a little flat (blurred, fuzzy – not crystal clear). I began to think (my downfall) about the fact that since both the clip and the TV are interlaced then maybe I should select ‘None’. The rest is not a pretty story. I read on one the boards that the best choice was ‘interpolate’. Needless to say, that wasn’t pretty either. So now I will render following your advice (which I personally hold in high regard). Thanks again for your patience.

Bob

[John Rofrano]

Let us know how you make out. If you have any other questions just ask… that’s how we all learn. 🙂

~jr

http://www.johnrofrano.com
http://www.vasst.com