Better for Broadcast QUALITY…DV50 vs Photo-Jpeg

[Jerry Hofmann]

I think DVCPRO50 compares favorably with digital Betacam… it’s in a 4:2:2 color space… and it’s all digital. Photo Jepg is always going to be coming from analog sources so… depending on the quality of the settings it could be as good or better, but it’s really apples and oranges. However DVCPRO50 blows the doors off DV 25 formats. It’s a lot better than they are.

Jerry

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[Martin Baker]

Yes I was probably one of those editors raving about it Lee. The DV50 codec is totally broadcast quality and I use it for more than 90% of the work I do. You’re right that there’s a lot of DV in broadcast these days but the regular DV25 and DV50 codecs are world’s apart in terms of quality. As regards comparison with PhotoJPEG (not sure what you mean by “analog PhotoJPEG”), the two are very similar but the big benefit of using DV50 is that it’s enabled for RT effects in FCP. At some point, I’ve stuck an uncompressed capture next to a DV50 capture of the same footage and it is impossible to tell them apart on screen. Even when you zoom right in to the pixel level, the difference is so negligible it’s not worth worrying about.

At the risk of tempting fate, the bottom line is that I’ve never had a problem with using DV50 in over a year and a half. DV50 just works great in FCP.

Martin
Digital Heaven, London UK
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[Lee Burrows]

Guys,

That is great information and I appreciate it. Tell me what you think of this thought.

DV is 25 to 1 compression while Photo-Jpeg is 2 to 1. Having said that then I assume that DV 50 is 12.5 to 1? If this is indeed true then isn’t Photo-Jpeg a better choice due to less compression?

Thanks

Lee

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[Jeff Carpenter]

DV is 25 to 1 compression while Photo-Jpeg is 2 to 1. Having said that then I assume that DV 50 is 12.5 to 1? If this is indeed true then isn’t Photo-Jpeg a better choice due to less compression?
=====

Well, first off, you’re getting numbers confused. DV is compressed at 5 to 1 (perhaps you’re thinking of 25 mbps?).

And I don’t think that means DVCPRO50 is 2.5 to 1…I’m not sure that it’s that simple. Although I have to say that I don’t know what DVCPRO50’s ratio is so I really can’t comment.

All numbers aside, however, you can’t really say that one is better than another based only on compression ratios. The KIND of compression matters a lot too. As a crude example, imagine simply cropping the top half of a video off so that the screen is half sized. That would be 2 to 1 compression, but clearly not as good as DV!

That’s a bit far fetched, but my point is that you need to look at HOW the space is being saved, not just how much is being saved. What’s being lost? Color sampling? Resolution? Entire frames (as in HDV). Depending on what you need, the “TYPE” of compression you’re talking about may be just fine or terrible. And it doesn’t always match up with which one has “more” or “less” compression.

[Tom Matthies]

Actually DV25 is 5:1 compression and 4:1:1 sampling. I believe that I read somewhere that DV50 is about 3:1. and 4:2:2 sampling. Digital Betacam comes in at 2:1 lossless. It’s also 4:2:2 but at 10-bit resolution. The two DV formats are 8-bit. You can probably see the difference if you look very closely and have the right source material. But, for a good general purpose codec, it’s pretty usable!
I too use DV50 a lot with no problems at all. It’s a good compromise between quality and file size. I use it for all local commercial work and have never had a problem. Hell, my spots generally go into the On-Air servers at the TV stations at a much higher compression rate than I use anyhow. Most of the quality loss I’ve experienced is in that final step going-into the station’s server. Yuk!
My 2

[Martin Baker]

Someone’s giving you really wrong information there –

DV25 is 5:1 compressed – 3.5MB/sec
DV50 is 3.3:1 compressed – approx 6.2MB/sec
PhotoJPEG isn’t 2:1 compressed, it uses a variable compression ratio depending on the complexity of the image.

Run your own test with an export to PhotoJPEG with the quality slider set to 75% and then do the same export to DV50. I bet the DV50 version is the larger file.

Martin
Digital Heaven, London UK
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[Lee Burrows]

Thanks everyone for the knowledge and advice. I’ll try the test and let you know what I find out. So I guess in the end its mostly about space as it seems that there are alot of broadcast quality options.

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[Graeme Nattress]

DigiBeta is 2.3:1, 4:2:2 10bit, and does indeed look better than DVCpro50. DVCpro50 is good, but PhotoJPEG75% will look better still. Indeed PhotoJPEG75% is an awesome codec, visually lossless, and is very useful for transfering media around at better quality than DV at lower data rates than DV. PhotoJPEG100% is 4:4:4 RGB and again useful, but not as useful as PhotoJPEG75% for video use. The only hitch with PhotoJPEG75% is that it is not RT enabled in FCP which is a shame. DVCpro50 is RT anabled, and is also excellent.

Graeme

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