Help me understand this at DVinfo.net

Mark Williams · March 2nd, 2006, 10:10 AM

I currently shoot in SD (DVC-30) to produce mostly DVDs with infrequent output to tape. The final product looks good but I want better so I was considering upgrading to the HVX200 using the DVCPRO50 format and change NLE software to Liquid 7 which according to accounts can handle this.

However, since I am producing DVDs, will the superior DVCPRO50 color space 4:2:2 be appearant. I thought I read that the DVD color space spec. is 4:1:1 and in the Liquid 7 manual it also notes output at 4:1:1. Please help educate me on this.

Regards,

Mark

Joe Hernandez · March 2nd, 2006, 10:38 AM

I believe DVD color space is 4:2:0. If you are outputting 4:1:1 from Liquid, you're most likely working with a DV codec and not DVCPRO50. In My opinion you can always benefit by originating your material in the highest quality codec even if you are delivering with a lossy codec like DVD.

Joe

David Heath · March 2nd, 2006, 10:50 AM

For both PAL and NTSC, DVDs are 4:2:0. In 50Hz countries DV25 is also 4:2:0 and translates well to DVD. In 60Hz countries, DV25 is 4:1:1 - so three in four colour samples are 'lost' horizontally, but there are as many vertically as luminance, compared to 4:4:4. Translate that to DVD, and the 4:2:0 coding then 'loses' every other vertical chrominance pixel, effectively leaving only 1/8 the original chroma pixels (sort of '4:1:0'). Using DVCPRO 50 means that there is originally only one in two chroma samples lost horizontally, the DVD translation leads to another one in two lost vertically, so a 'true' 4:2:0 end product results. DVCPRO 50 is also less compressed anyway, but it's relevance in your case is not so much that it is 4:2:2 as it is NOT 4:1:1.

In 50Hz countries this is much less relevant as DV and DVCAM are both 4:2:0, and hence don't lose colour samples when translating to DVD. DVCPRO is 4:1:1 in PAL, but that is much less common.

But if you're getting an HVX200 why not just shoot and edit in HD anyway, and downconvert from that? That way you maintain a HD master.

Gene Brockhoff · March 2nd, 2006, 11:08 AM

Here is an in-depth article on understanding color sampling: http://www.kenstone.net/fcp_homepage..._nattress.html

Robert Lane · March 2nd, 2006, 11:15 AM

Hi Mark,

David brings up a valid point. Although most of your work now is SD, the HD-DVD players will proliferate the market within the next 16 months as consumer driven factors lower the costs and bring volume up.

As we are doing with all our projects going forward, we are shooting in DVCPRO-HD and down-converting for SD-DVD output. However, we're keeping the HD masters so we can then re-cut and re-relase the HD versions when the HD-DVD players become plentiful in the consumer market.

It's been a hotly debated topic for over 2 years now: Would a typical SD output - especially to DVD - look better if it were shot in HD and then down-converted to SD? Our own testing proves, "yes", there is a significant quality difference between the two. Obviously current DVD compression knocks down both color and resolution, but if you consider that SD DV is compressed much more than any DVCPRO codec, you're better off shooting in that mode than not.

However, even if we weren't shooting HD, I'd still shoot in DV50 and the get the better 4:2:2 color space to begin with rather than DV25.

The general rule of thumb, is to shoot in the best codec you can afford. That way you have more output options for now and the future.

Mark Williams · March 2nd, 2006, 11:28 AM

Thanks guys, this has cleared it all up for me.

Regards,

Mark

Mark Williams · March 14th, 2006, 09:10 AM

Just an update on this. I received an e-mail from Marianna Montague with customer service at Avid. She informed that Avid has just released a demo version of Liquid 7. This should give us an opportunity to play with DVCPRO 50. The link is:

http://www.avid.com/forms/infoLiquid...LDVDPRMBTNQ106

Its not available for download. They send you a DVD copy.

Regards,

Mark

Hans Damkoehler · March 14th, 2006, 10:14 AM

Quote:

Originally Posted by Robert Lane

As we are doing with all our projects going forward, we are shooting in DVCPRO-HD and down-converting for SD-DVD output. However, we're keeping the HD masters so we can then re-cut and re-relase the HD versions when the HD-DVD players become plentiful in the consumer market.

Hey Robert!

The following questions aren't the main point of this thread but since you mentioned them and I've been wondering, I'm asking!

How are you retaining your HD-Masters? To tape? A file? Are you creating an HD DVD in Studio Pro?

How are you archiving (or are you) your master shooter footage?

Any pointers on your down-conversion technique? What do you guys use to encode? Compressor? Hardware? Any settings you find helpful?

Sounds like a new thread but here I am. Thanks man! Hope all is well with you.

March 2nd, 2006, 10:10 AM	#1
Mark Williams Trustee Join Date: Dec 2002 Location: Deep South, U.S. Posts: 1,526	Help me understand this I currently shoot in SD (DVC-30) to produce mostly DVDs with infrequent output to tape. The final product looks good but I want better so I was considering upgrading to the HVX200 using the DVCPRO50 format and change NLE software to Liquid 7 which according to accounts can handle this. However, since I am producing DVDs, will the superior DVCPRO50 color space 4:2:2 be appearant. I thought I read that the DVD color space spec. is 4:1:1 and in the Liquid 7 manual it also notes output at 4:1:1. Please help educate me on this. Regards, Mark

March 2nd, 2006, 11:08 AM	#4
Gene Brockhoff Regular Crew Join Date: Aug 2003 Location: Oakland CA Posts: 46	Here is an in-depth article on understanding color sampling: http://www.kenstone.net/fcp_homepage..._nattress.html __________________ "We are basically free, but who we think we are is not" Ram Dass

March 2nd, 2006, 10:38 AM	#2
Joe Hernandez New Boot Join Date: Dec 2005 Posts: 8	I believe DVD color space is 4:2:0. If you are outputting 4:1:1 from Liquid, you're most likely working with a DV codec and not DVCPRO50. In My opinion you can always benefit by originating your material in the highest quality codec even if you are delivering with a lossy codec like DVD. Joe

March 2nd, 2006, 10:50 AM	#3
David Heath Inner Circle Join Date: Jan 2006 Posts: 2,699	For both PAL and NTSC, DVDs are 4:2:0. In 50Hz countries DV25 is also 4:2:0 and translates well to DVD. In 60Hz countries, DV25 is 4:1:1 - so three in four colour samples are 'lost' horizontally, but there are as many vertically as luminance, compared to 4:4:4. Translate that to DVD, and the 4:2:0 coding then 'loses' every other vertical chrominance pixel, effectively leaving only 1/8 the original chroma pixels (sort of '4:1:0'). Using DVCPRO 50 means that there is originally only one in two chroma samples lost horizontally, the DVD translation leads to another one in two lost vertically, so a 'true' 4:2:0 end product results. DVCPRO 50 is also less compressed anyway, but it's relevance in your case is not so much that it is 4:2:2 as it is NOT 4:1:1. In 50Hz countries this is much less relevant as DV and DVCAM are both 4:2:0, and hence don't lose colour samples when translating to DVD. DVCPRO is 4:1:1 in PAL, but that is much less common. But if you're getting an HVX200 why not just shoot and edit in HD anyway, and downconvert from that? That way you maintain a HD master.

March 2nd, 2006, 11:15 AM	#5
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	Hi Mark, David brings up a valid point. Although most of your work now is SD, the HD-DVD players will proliferate the market within the next 16 months as consumer driven factors lower the costs and bring volume up. As we are doing with all our projects going forward, we are shooting in DVCPRO-HD and down-converting for SD-DVD output. However, we're keeping the HD masters so we can then re-cut and re-relase the HD versions when the HD-DVD players become plentiful in the consumer market. It's been a hotly debated topic for over 2 years now: Would a typical SD output - especially to DVD - look better if it were shot in HD and then down-converted to SD? Our own testing proves, "yes", there is a significant quality difference between the two. Obviously current DVD compression knocks down both color and resolution, but if you consider that SD DV is compressed much more than any DVCPRO codec, you're better off shooting in that mode than not. However, even if we weren't shooting HD, I'd still shoot in DV50 and the get the better 4:2:2 color space to begin with rather than DV25. The general rule of thumb, is to shoot in the best codec you can afford. That way you have more output options for now and the future.

March 2nd, 2006, 11:28 AM	#6
Mark Williams Trustee Join Date: Dec 2002 Location: Deep South, U.S. Posts: 1,526	Thanks guys, this has cleared it all up for me. Regards, Mark

March 14th, 2006, 09:10 AM	#7
Mark Williams Trustee Join Date: Dec 2002 Location: Deep South, U.S. Posts: 1,526	Just an update on this. I received an e-mail from Marianna Montague with customer service at Avid. She informed that Avid has just released a demo version of Liquid 7. This should give us an opportunity to play with DVCPRO 50. The link is: http://www.avid.com/forms/infoLiquid...LDVDPRMBTNQ106 Its not available for download. They send you a DVD copy. Regards, Mark