Getting to Blu-ray with 1080P25 footage??
 

I'm using Matrox's CompressHD card and Compressor (Mac workflow) but always get stuttery jerky playback. I've tried to put the 25P in a 50i sequence and also conforming to 24P with Cinema Tools, but same results. Any help here greatly appreciated. What a nightmare not having 25P as a Blu-ray standard when most serious cams in Pal land record in that format.

Keep in mind that 50i is twice the temporal resolution of 25p. Did you use Frame Controls when encoding for Blu-ray to convert your progressive video to interlace.
This is a good read. Not specific to Blu-ray but it does talk about going from progressive to interlace.

EX1: Downconverting

BTW another route to go would be to convert 25p to 24P which is Blu-ray spec. You'd just need to do a speed change.

Hi Craig,

Thanks for that info, interesting about the frame controls, never knew that, very useful to know and I'll try that when scaling down to SD DVD next time.

I did try to conform from 25P to 24P with Cinema Tools, is that the correct method, I think I got that from Graeme Nattress somewhere?? And then I was going to pitch shift the audio if need be if it sounded slow and low, but I didn't get that far as the video was choppy as anything, like it was repeating frames every half second or so, almost like it was stepping backwards a frame before carrying on.

As a matter of interest, if I was successful (fingers crossed!) in making a 1080 24P Blu-ray from a 25P sequence, what happens when a client puts it in a player which doesn't have 24P capabilities? And for that matter tries to view it on a non-24P display?

Thanks very much for any input.

You just need to speed change 25p to 24p unless you're trying to do something like "re-flag" the time base. You can just do a simple speed change and compensate for the audio's pitch shift.

24p is part of the Blu-ray spec so all players should handle I believe . . . unless there's something I don't know about players made for PAL compatible countries. Heck many PAL DVD players handle NTSC (although not quite the same as NTSC players).

BTW you do know you can set the source to progressive in CompressHD? Perhaps that was also part of the problem.

I need your help here Craig as I am about to take up a project from which the end delivery will be Blu-ray. I have googled and visited the official Blu-ray website but could't find the info about compatible framerates in the Blu-ray specs. I now know 24p is one of them and 25p is certainly not. What about the others? 60i or does it have to be 60p? 50i, or have to be 50p?

I ask this question because I suspect the Blu-ray standard may rely on the 24p and 60i as opposed to the 25p and 50i frame/field rates. If this is the case for Blu-ray, I'd better shoot the footage using NTSC or 24p/60i capable cameras to avoid getting bogged down in post dealing with timing conversion, audio stretch, frame interpolation etc. and all the stresses, not to mention time, these will cause to my rather low-end editing system.

Thanks
Wacharapong

1080 60i, 50i, 24p
720 60p, 50p, 24p

Bunch of good stuff here
EMediaLive.com: The Authoritative BD FAQ: II. Physical, Logical, and Application Specifications

Awesome post.

Bookmarked

Compensate for the audio's pitch shift.
 

What process-work flow are you using to do a pitch shift, speed change to the audio?

Crystal clear, Craig. Thanks for posting the link. I didn't even know there were some other things else I should have known!

On Mac if you have Final Cut Studio, SoundTrack Pro will do speed change and compensate for pitch.

Many mid range audio apps can do this. I would expect Adobe Audition can do this on Windows.

It's amazing how difficult it is to find this stuff. You'd think it would be obviously explained on the official Blu-ray site in a white paper or FAQ.

emedialive used to be a magazine that evolved into EventDV (primarily wedding video) and the parent company has StreamingMedia also (which is streaming of course) so the Blu-ray stuff is kinda lost from their current print publications (I think I have my magazine history correct). Fortunately emedialive still has their stuff online.