24P preset run length duration limit DVDSP Studio Pro real practical size answer want

rjcam

rjcam

Active member
Hi,

What are the real program length size limits AND do we really get a file size bump advantage using pure 24P? We should and it's said we do but I don't think I see it in practice.
2.5 hrs total film length I want to encode (really 2 hr 25 min), onto 1 single layer DVD as a goal (using 5.0 Mbps Compressor preset).

To wit, using COMPRESSOR (3.x) and it's built in 5.0 Mbps 120 minute (for 29.97 rate calculated) (Best Quality 2 Pass VBR) encoding is supposed to allow 2 hr at 29.97 rate in a standard 4.7GB single layer DVD.
I have a pure 24P (using DVX100 footage shot at 24P normal using CineTools to remove the pulldown and edit in pure 24P timeline in FCP 6.04).
I export the timeline to Compressor keeping the 24P frame rate (verified in the first box that comes up).
I SHOULD get a 25% net gain, making, say a 2 hr 30 min 24P program fit in the same space as a 2 hr 29.97 on a regular single layer disc. I am not seeing any gain in size.

QT, DVDSP, Compressor all 'see' my made file as 29.97 frame rate, but I understand this is an 'error' it's making in assessing the asset, because the frame rate it's assessing is something like the final viewing on the made DVD - it's really reporting the flags to insert the pulldown for interlaced DVD players and TV sets etc...

SO what is the deal here?*
Does this not make sense that I get a size advantage like it's touted everywhere that I will? In fact less frames are used, and the material is smaller file size, but DVDSP doesn't see it that way, NOR does the file size.

I encoded an exact 30 min test length of my 24P program.
Result?:
video: m2v at Compressor's*5.0 Mbps preset = 1.04 GB
audio: ac3 = 41MB
30 min total = 1.08 GB
---
2 hr would be above x 4 = 4.32 GB very close to the limit DVDSP can handle in reality.
2.5 hr would be above x 5 = 5.40 GB size - clearly above a 4.7 (4.5) GB single layer disc.
So I am displaying NO GAIN in file size by encoding at pure 24P. What gives?

searched around online all over many many searches and I come up with nothing, no answers. This is holding up my project for months now, any assistance greatly appreciated!
 
Well, I don't work with Compressor, but I get a smaller file when rendered from Vegas (it's actually 20% smaller than the equivalent NTSC file, not 25%). I do know that others have given me 23.976 DVD files made from Compressor, which read as 23.976. Perhaps your settings in Compressor are off.
 
Well that's an interesting idea. I have checked it a few times, and it seems to be right, but either it's off, there's a glitch, or something else?
Is there an extremely complicated and lots of small boxes to check / reset within Compressor to output a sent in 24P FCP file as 24P?
Thanks
 
Well so do I not get something here?
I have QT pro with a plugin or two and I opened the made .m2v file and it is able to verify the frame rate IS 23.98 (not 29.97).
So that's good. But my file is still porky - apparently taking up the same amount of space an identical 29.97 program would take using Compressor's built in 5.0 Mbps Best Quality preset.
SOO... what gives?*
Is Compressor on the fly jacking up my bitrate to fill in what it thinks I want for file size? (in this case making the file 20% larger than if I had made the same length a 29.97 output file?) I doubt it, Compressor seems not up to that.
 
Don't get too hung up on picking up an exact 20% gain just for going to 24p, the encoding gets padded by the second not on every frame so it's not a 1:1 difference. And the built-in presets are just that- presets. To get the best bang for the buck you need to optimize your own settings- and in this case that would require a handy bitrate calculator:

http://www.videohelp.com/calc.htm

Also to fit that long a movie onto a Disc at optimum quality I'd go ahead and go dual layer. the burner is cheap as are the discs these days...

I happen to have a $10 video course which explains step by step how to make 24p DVDs from the DVX100 using Compressor and DVD Studio Pro: http://www.callboxlive.com/collecti...-production-with-final-cut-pro-and-the-dvx100

-Noah
 
I might make a dual layer, but I really don't want to. I have plenty of burners, just no media on hand.
This SHOULD work. 150 min of pure 24P material should roughly equal 120 min of 29.97 material. That would be a 20% gain.
I exported to Compressor my program at 150 min 3.7 Mbps prest Best Qual but I'd much rather bump it up to 120 min 5.0 Mbps preset Best Qual.

ALSO - I know about the odd display problem with DVDSP and Compressor for that matter. Let's call it what it is - an error and bad programming. I know it's reading the flags but does ONE editor in the world care about that and want to see that false reading rather than freak out that Compressor sold you down the river and made a 29.97 conversion in secret?
Now that said, I read in DVDSP if you select the imported video clip in the ASSET window and click on the inspector it will read properly the rate - 24 or 23.96 * But I don't get that reading there, it still says 29.97 plus at the 3.7 Mbps rate I am clocking in a 4.7 GB final sized disc. It should be a fair amount smaller, like almost a gigabyte smaller.
So again, is Compressor botching export?? I am sending it a pure 23.96 timeline out of FCP. I use 'current' frame rate which Compressor shows as 23.96. And even in QT Pro my final .M2V indicates it's at 23.98
 
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The timecode in DVDSP is reported as 29.97 based timecode because that's what a DVD player displays. But if you encoded as 23.98/24p in Compressor properly the result is a 24p native MPEG-2.

Don't be taken in by the "Best Quality" in the preset- that name has zero effect on the actual quality. Image quality is entirely controlled by the bitrate you choose. Don't forget to encode audio to AC3 as PCM eats up tons more audio. 3.7 MBPS is still too high for 150minutes. I'd aim for 3.4 or less to hit 4.2 GB in the final- which is the absolute max for a single layer disc- assuming no other footage or motion menus on the disc.

And again to reiterate- don't expect this to look much better than VHS. Anything longer 90 minutes is what I would consider a dual-layer amount of footage for the best DVD can look. If you don't want to use the right media then it's not really DVDSP's fault for the results.

-Noah
 
What I find most perplexing and IS my question specifically is this:
why am I seeing NO space / size savings using Compressor with a pure 24p FCP project versus the same file size if had been at merely 29.97?
i don't care to get into quality and bit rate debates and issues. I understand bitrate. That's why I shoot DVCPRO cameras and not cheap Sonys.
 
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