24p and 30p (60i) on same Blu-ray project

G

Galleddrim

Active member
Hello, all! First post. Looks like a great community here at DVX, so I'm happy to be here.

Okay, now for my question. I am looking into workflow and shooting options for HD wedding videography, delivering on blu-ray. I was wondering if it is possible to have multiple frame rates on the same disc. For instance, I might want to use 24p for more narrative segments of a video and use 30p for more documentary-style segments. The final result would probably be really subtle, but noticeable, even if most people wouldn't be able to figure out what the exact difference is.

Just a brainstorming idea. Is it at all possible? Thanks for any help or advice.
 
You can have a mixed format blu-ray, but they have to be on different playlist & title

30p is never a legal format for blu-ray primary, you would have to use 60i. (blu-ray secondary can have 720x480p29.97 only if the primary is progressive as well)
 
Okay. So you can't have a 60i shot following a 24p shot in the same title. Got it. I know about 30p not being part of the blu-ray standard. I am under the impression that 30p needs to get converted to 60i for blu-ray delivery. Is that incorrect?
 
Galleddrim said:
Okay. So you can't have a 60i shot following a 24p shot in the same title. Got it. I know about 30p not being part of the blu-ray standard. I am under the impression that 30p needs to get converted to 60i for blu-ray delivery. Is that incorrect?
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30p => 60i conversion is problematic because true 60i is 60 fields per second (i.e there are 60 moments in time for 1 second) , but your 30p source only has 30 moments in time. If you had a 60i source, you could bob-deinterlace it to 60p and use 1280x720p/59.94

If you had a 30p source, most people would make it a fake 60p i.e 1280x720p/59.94 by duplicating frames. The true temporal resolution is still 30p, you are just doing this to make the signal compliant.

The other options are frame interpolation to 24p or 23.976p - this will lead to varying degrees of artifacting depending on your software , but will provide a smooth experience. The other methods of framerate conversion are straight decimation and frame blending to those legal rates but they are usually worse because jerky playback with decimation, and blurriness with blending
 
What about using 23.97 with 24p (e.g. a consumer cam that converts 60i to 24p like the HF canon series)?
 
What about using 23.97 with 24p (e.g. a consumer cam that converts 60i to 24p like the HF canon series)?
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They can't be on the same title. Convert one to the other if you are intermixing footage. (I assume you meant 24.00 vs. 23.976)

A proper pulldown removal on those streams will return 23.976 (or really 24000/1001)
 
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