50i vs 60i

M

Mike Caffrey

Member
Is it correct that with a Z1U at 60i you get 4:1:1, but when you switch to 50i you get 4:2:0?

I'm pretty sure it is, and as near as I can tell, there is a noticable change in the look.

Can anyone generalize about what's gaine and what's lost switching from 4:1:1 to 4:2:0?

If I like the appearance of 50i better, when is the best time to convert, coming ou of the camera into FCP (which would be a real pain for me) or after I edited and was doing my final output.

There's defintiely something that "pops" a little more at 50i, so that's why I'd consider this approach. Beyond render time, are there any big reasons not to work this way?
 
In DV, yes. In HDV, no -- they're both 4:2:0.

For more on that subject, look in the "Articles" section for the "Understanding Color Sampling" article.
 
Is it correct to say that the color sampling is the same, but the difference between 4:1:1 is and 4:2:0 is that in the former the color averaging is done in a line annd in teh latter is done in a cube (in terms of pixels)?

In DV, which I switch between the two am i seeiing a difference from teh power of suggestion or does the subject and the lighting create different effects between the two?

Would I be crazy to shoot in 50i for the 4:2:0 and convert to 60i for my final output?
 
I don't think you can see the difference between color space (unless you're an X-Men). I don't think it's a question of colorspace so much as a question of resolution. In HDV you're getting a huge resolution that you can later downconvert to SD; whereas if you choose to shoot DV then all the advantage is gone. You should start out with the best you can get in term of image information so that you have more option.

I don't see why you would want to shoot 50i and then convert to 60i (i'm not even sure how that would work out in term of frame rate). 50i is better than 60i because it's easier to deinterlace to 25p for that film motion. Unless you want to do slow motion then you should shoot 60i for the maximum amount of frames.
 
Mike Caffrey said:
Is it correct to say that the color sampling is the same, but the difference between 4:1:1 is and 4:2:0 is that in the former the color averaging is done in a line annd in teh latter is done in a cube (in terms of pixels)?
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Yes, that's exactly the difference.

In DV, which I switch between the two am i seeiing a difference from teh power of suggestion or does the subject and the lighting create different effects between the two?
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In DV, PAL has 20% more resolution than NTSC. That's probably what you're seeing.

Would I be crazy to shoot in 50i for the 4:2:0 and convert to 60i for my final output?
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Yes, but hey, try it and see if you like it. I would expect that the frame rate conversion and rescaling will destroy any benefit you believe you're seeing, and the net result will be notably inferior to just normal 60i origination in the first place. And then compound that with the rendering time and it seems like a lose-lose proposition.

But run a test, because hey, if you prefer the results, that's all that matters.
 
Barry_Green said:
Yes, that's exactly the difference.


In DV, PAL has 20% more resolution than NTSC. That's probably what you're seeing.


Yes, but hey, try it and see if you like it. I would expect that the frame rate conversion and rescaling will destroy any benefit you believe you're seeing, and the net result will be notably inferior to just normal 60i origination in the first place. And then compound that with the rendering time and it seems like a lose-lose proposition.

But run a test, because hey, if you prefer the results, that's all that matters.
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Thanks so much for taking the time to answer.

I don't mind the render time, especially becuase I'm about to buy an absurdly fast G5 and for me, video is just a piece of what I do. I don't have lots of deadlines and I can let things render overnight.

20% more resolution in DVD sound interesting to me. Why would there be more and if I'm seeing greater resolution, is it in the color or luminance or contrast ro something else?

I'm especting to do som B&W shortly too, will I still have the greated resolution? And, if you dont record color, does that mean there's less compression needed for the HDV format? And maybe more importantly, if they need less, does it in fact work that way?


Suppose the final output will be Quicktime movies? I'm not sure if this is correct, but I think of Quicktime as it's own thing, and that outputting to Qucktime means a conversion whether you coming from 50i or 60i or DV or HDV.

So, if the distribution was the web, or some other compressed Quciktime file, does that change things? 50i compressed compared to 60i compressed? Does that extra resolution help the results when it's further compressed?

What about 50i -> FCP -> Quicktime -> iDVD? Is that going to be a problem to play in a computer or a standard American DVD player?

Or, will 50i always reqire a conversion that 60i won't no matter where you're trying to output it to?


I understnad that ultimately, I have to the view the "lower-fi" quality that comes from the conversion and see if I like it better. What I seen in the camera viewfinder defintiely looks better.
 
Mike Caffrey said:
20% more resolution in DVD sound interesting to me.
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If you're releasing on NTSC, you won't have 20% more. NTSC = 720x480, PAL = 720x576. PAL, as a video standard, has 20% more resolution. But if you're converting it to NTSC you'll be giving up that resolution, plus more, because you'll also be blending fields together to try to overcome the frame rate difference.

And, if you dont record color, does that mean there's less compression needed for the HDV format? And maybe more importantly, if they need less, does it in fact work that way?
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Haven't tested that, but I would certainly expect it to work that way.


Suppose the final output will be Quicktime movies? I'm not sure if this is correct, but I think of Quicktime as it's own thing, and that outputting to Qucktime means a conversion whether you coming from 50i or 60i or DV or HDV.
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Quicktime is just a container, it can hold whatever you want, so it could hold unmodified 50i DV, unmodified 60i DV, raw HDV, or whatever. Or you could convert it to Sorensen or AVC or any other number of codecs.

So, if the distribution was the web, or some other compressed Quciktime file, does that change things? 50i compressed compared to 60i compressed? Does that extra resolution help the results when it's further compressed?
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If distribution is for the web, using an interlaced camera is certainly not the optimal way to go. You'd be better off using a progressive camera for those cases.

What about 50i -> FCP -> Quicktime -> iDVD? Is that going to be a problem to play in a computer or a standard American DVD player?
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American DVD players cannot play 50i or any variation thereof. Our players support 60i, or 24p, that's it.

Or, will 50i always reqire a conversion that 60i won't no matter where you're trying to output it to?
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For the US, yes. For Europe, you can release as either 50i or 60i or 24p, their players support all those modes.
 
Thanks.

Today I tool a video I shot with a Sonyhandy Cam and opened in in Cinema Tools by accident. Since I didn't know was reverse telecine is, I processed the file to see what would happen. Then I opened the original and the reversed file in Quicktime, and then reversed file looked much better. What exactly did I do?

I did a websearch and ony vaguely follwed the explanation. It seems that I to an interelaced video and converted it to 24p. IS that correct?

I've tried this with a bunch of files and it seem that the only ones I can convert are raw DV files, not HDV or anything already compressed.


Also, playback (before any kind of processing) looks far better in Cinema Tools than in Quicktime. Why is that?
 
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