DVCPRO-HD vs DVCPRO-50

[dglasgal]

Someone please explain why DVCPRO-HD's compression ratio is 6.7:1 and DVCPRO-50's seems to be better at 3.1:1. Wouldn't the least compressed signal be the best? I know there is a fancy, or really simple answer to this- anyone?

Thanks

David

[mmm]

DVCPRO 50 is an SD codec and so has far less data to compress. Therefore the compression ratio is lower.

[Barry_Green]

One is high-def, and the other is standard-def.

DVCPRO-HD has 4x as many pixels, but twice the bandwidth (100 megabits versus 50 megabits). So it has to be twice as compressed to fit in its allotted bandwidth.

[dglasgal]

Thanks! overlooked that part of the ratio definition.

[Brett Erskine]

So it sound like if your only going to regular DVD with no major plans for HD delivery in the future then you will have a better looking image if you shot it in the less compressed DVCPro 50 format rather than DVCPro HD. Is that correct?

Or is it actually the other way around because by downcoverting from DVCPro HD to SD you might gain some extra clarity that you would not have had had you shot in DVCPro 50 in the first place

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[Stevet]

I believe from Barry's DVCPRO50 comparison test, (I) learned the following info:

1. DVCPRO50 produces a better image. The higher color space and lower compression looks better than straight DV (MiniDV).

2. If you need to downsample from 1080 or 720, if image quality is of highest concern, do not down rez in the camera. Use an external program to down rez your HD.

3. Using decent external software, HD looks very good down rezzed to 480, better than MiniDV. It appeared to be very close to the DVCPRO50.

When I get my HVX, I plan on running some tests myself.
My intentions are mainly to shoot HD anticipating Blu-Ray or HD-DVD this coming year. I want to down rez to DVD.

I want to be able to offer the HD footage when the time HD DVD becomes more of a reality.

[Brett Erskine]

Thanks Stevet. I wasnt really considering standard DV format 4:1:1 as a option since theres no question it cant compare to DVCPro HD and DVCPro50.

My questions is in order to make the most of the image quality for standard def DVD delivery ONLY should one shoot in the more compressed DVCPro HD and down convert (possible gain in clarity?) OR should it be shot in the less compressed DVCPro50 at standard def (for the better color space/compression)? (see my post above)

Anyone with links to test or first hand knowledge on this?

[LowDown]

Brett,
I can only attest to the great quality of dvc pro50. I try and shoot all of my sd projects on an sdx900 and love the results. Yesterday I shot a Hallmark commercial on it and it is so much better than dv25. (last week I shot 3 days on the dvx for sam's club so I am not averse to using the dvx.) If you or anyone else want to see the quality of dvcpro50 then watch "rollergirls" on A&E - monday nights 9Central.
Regards,
Shane

[brianluce]

Walter Graff has commented that although the dv50 is a better format, 1/3" chips are a limiting factor and will hamstring the performance of the dv50 codec. That in the final analysis, the codecs won't make much difference. That's how i understood his claim at least.

I'm hoping for more real world testing to either confirm or refute Walter's assertion. His assertion seems logical and reasonable but is currently not backed by empirical evidence. any takers? I just don't think the whole codec thing has been addressed and tested especially in regards to the SD formats.

[Stevet]

Brian, Walter Graff is a smart man, no doubt

Did you see the thread Barry had displaying HVX200 SD frame grabs of
MiniDV , DVCPRO50, HD downsampled in camera, and HD downsampled outside of camera.

It was NO CONTEST that DVCPRO50 smoked the miniDV frames.
All Barry did was switch the format, no other adjustments were made.
It was dramatic.