Can you output uncompressed?
 

Hi there all. Im learning about ways to improve quality in my productions and I heard that it might be possible to output in a uncompressed form and input into my avid liquid editor as uncompressed then edit etc. Is this possble?

It is possible with most programs, although your hard drive is going to suffer. Hefty file sizes.

Im assuming you dont output from the dv connection. Which one do you output from? Also what is the quality difference between compressed and un compressed given that I have plenty of hard disc space? Any advice would be appreciated to help clear this up.

If you mean output compressed from your XL2 and capturing the uncompressed stream on your computer, then it is not doable with a retail XL2. The firewire carries the DV compression and is not uncompressed.
Perhaps there are som "guerilla" solution to a uncompressed stream being captured right of the ccds, but I personally don't know about that.
There is the andromeda for the dvx, but thats another discussion.
So the answer would be no, but some people capture through the S-video connector for some reason that I don't quite understand.

regards

He doesn't want input/capturing, he said output. I'm assuming you mean Render?

To output or render uncompressed go to your render settings and just turn them all the way up on everything. The file size is going to be extremely lofty depending on the program, how hefty the editing is, and your footage.

To give you an idea, I just made a 34 second short with simple invisible editing (simple cuts and takes) that was 43MB on the render. That is quite hefty for 34 seconds.

Hope this helped.

Thanks for the replys.

So does that mean that you output from your camera in dv compression into your computer that you set to accept an uncompressed signal? I was thinking that this is still compressed and that maybe the S video or video RCA/BNC could possibly be different. Is any signal coming out of the XL2 compressed no matter which output we choose?

Hi Anthony. The firewire output is ALWAYS compressed, whether it is a live feed or played back from the tape.

The analogue output is also compressed when it is played back from tape, and it is rumoured to be uncompressed when it is a live feed. I say rumoured because I haven't seen any confirmation of this. If it is really uncompressed, and you have suitable hardware to capture it with, you should see some benefit in the larger colour space compared with DV 4:1:1 or 4:2:0. Whether this offsets the reduced bandwidth of an S-Video connection I am not sure.

Richard

I'm pretty sure this isn't the case. The DV compression occurs in between the ccd's and any outputs.

One way to test for sure is to video a bright red object; make sure it is lit well. When you capture this, if it is compressed you should notice some pixelation around the edges of the red object.

There are ways to get rid of this pixelation to some degree. In after effects, duplicate your video layer, apply about 2 or so pixels of gaussian blur to it, then set the layer mode to "color"

Basically you’re blurring just the color channels, which are the ones that are compressed.

Hi Jonathan. As I said, I just don't know if the analogue outputs are uncompressed or not. But I'm not sure if your test will show up DV compression specifically, or just colour sub-sampling in general. Even "uncompressed" YUV video will be 4:2:2 rather than 4:4:4, so it is possible to see sampling artifacts if you look closely enough.

Richard

Actually, I have seen a video floating around that would support that the Canon has 4:2:2 uncompressed video out of the s-video. It was some greenscreen work where the feed was recorded via a decklink card I believe and also recorded to DV. The final keyed footage sure supported the assertion that the XL2 s-video out is pre-compression...




ash =o)

If that were true (and I'm not saying it is or isn't), wouldn't that be something that would have been very advantageous for Canon to have been advertising all along?

Yes. It's probably true then. :)

This discussion came up some time ago and like Ash, I have seen some video that supports the possibility that the S-Video output is pre-compression when taken live. It was a DVINFO reader that emailed it to me privately because it was a commercial for a client.

Still, others have tried this and claim it doesn't come out any better than using DV over firewire. I don't have my XL2 cameras anymore so I can't confirm. I strongly suspect that it has a lot to do with the quality of your analog capture device and what it does to the video upon capture.

Since no one has access to the XL2 schematics, it's hard to verify this claim.

-gb-

This may be a hint - from Page 96 in the XL2 Manual,

"You can copy your recordings by connecting the camcorder to a VCR or digital device. If you connect a digital video device, you can copy recordings with virtually no generation loss in image and sound quality."

By deduction, if it doesn't further compress a "recording," then it shouldn't compress the original signal. 'Course, I've had no sleep, and waaay too much coffee, so cut my reasoning a little slack.

Has anybody come up with a confirmation on this topic yet? I am really interested in an uncompressed output for a short that I have in mind. Can the XL2 output uncompressed either via S-Video or BNC? If so, what is the best, easiest, way to record an S-Vid or BNC output (preferrably digital)?