SDI/HD question

[Daniel Patton]

Can someone either point me to a good thread, or take a minute and tell me what formats are supported out via the SDI as HD on XH-A1? I was told that to go directly out SDI (ignoring tape for the time being) as progressive "Frame" mode that I might notice a resolution drop. Can this be explained with numbers as well please?

Is there a setup on the BlackMagic card /NLE that works with the cameras uncompressed Frame mode?

[David W. Jones]

The A1 does not have an SDI port.

[Daniel Epstein]

David is correct you need the XH-G1. The resolution drop happens in the way Canon makes the frames for 24F and 30F and should the same for both tape and HDSDI out.

[Nate Weaver]

The resolution drop is something I've only seen in charts, not real footage. In practice it's hardly there.

[Larry Vaughn]

Do you get the same signal from the component out and the firewire ports? Is this HDV or something else? They both work without any tape in the camera.

[Dick Nelson]

Larry,

The component outputs on the XH-A1 will give you analog components, suitable for a digitzing card that takes analog component inputs. The firewire spigot will give you either the HDV digital stream or a DV digital component stream, depending on your camera's settings.

Dick Nelson
Silverthorne, CO

[Daniel Patton]

Originally Posted by Daniel Epstein

David is correct you need the XH-G1. The resolution drop happens in the way Canon makes the frames for 24F and 30F and should the same for both tape and HDSDI out.

Ah, got it. Thanks for the model clarification. I'm curious about the actual size of the resolution drop, what is the actual frame size when going 24F & 30F? Is it a square pixel?

While on the subject, how about the XL-H1 is it the same size/format through SDI as the XH-G1? I won't see our H1 in for another week but I also wanted to compare the smaller Canon hand helds, hence all the questions.

And thanks Nate, I was wondering how well the XH-G1 and XL-H1 SDI images will hold up, even more so when keying. Our JVC HD100 did a fair job via compnent, but nothing compared to the HD250 via SDI we also are looking to order. The H1's intended use is more run and gun but it would be good to use it in the studio as well.

[Larry Vaughn]

It does say that on the camera regarding the firewire port. I'm wondering what mods would be necessary to get to the non compressed video.

There is an adapter that will output time code, for example, by using the lanc terminal.

Somehow maybe there is a back door to the HD stream without paying 3K for the jackpac in the XH-G1.

[Daniel Epstein]

Originally Posted by Daniel Patton

Ah, got it. Thanks for the model clarification. I'm curious about the actual size of the resolution drop, what is the actual frame size when going 24F & 30F? Is it a square pixel?

While on the subject, how about the XL-H1 is it the same size/format through SDI as the XH-G1? I won't see our H1 in for another week but I also wanted to compare the smaller Canon hand helds, hence all the questions.

And thanks Nate, I was wondering how well the XH-G1 and XL-H1 SDI images will hold up, even more so when keying. Our JVC HD100 did a fair job via compnent, but nothing compared to the HD250 via SDI we also are looking to order. The H1's intended use is more run and gun but it would be good to use it in the studio as well.

It is hard to answer the resolution question although there are some good tests. The frame size stays the same but the resolution measures differently on the charts. From memory in 60i the charts had the XLH1 at around 800 lines while at 24F it measured around 540 lines. I believe the pixels are not square in HDV because 1440x1080 ends up covering 1920x 1080 worth of area. See the Manual on Page 97 for explanations. Different outputs have different numbers pixel outputs.

The chip block and processor are supposed to be the same on the XLH1 and XH G1 and XHA1. The only difference in the SDI is the XLH1 doesn't include the audio or timecode while the XHG1 also has the audio and maybe the timecode

One of best things can be said about the XLH1 is the HDSDI output is before the Mpeg HDV compression. If you can record the signal it should give you a better key than the analog output. The extra resolution of 1080 might win out over the progressive 720 of the JVC or it might not. Both should work well

[Daniel Patton]

Thanks for the info Daniel!

I would sure like to get some clarification on this however...

"The only difference in the SDI is the XLH1 doesn't include the audio or timecode while the XHG1 also has the audio and maybe the timecode".

No audio in the SDI? Serious? I thought that was a selling point on the H1 when it first came out. Or maybe I'm thinking of another camera.

[Dick Nelson]

Quoting from Adam Wilt's first look at the A1/G1:

"The Canon offers 24F and 30F modes in addition to 60i. F modes
use the same vertical pixel shift as the XL-1's Frame Move Mode,
running the green CCD a field out of phase with the red and blue
CCDs. Aliasing sets in at 540 lines of vertical resolution, and fine
vertical detail can show color moire, but the image remains
perceptually sharp, better than simple field-doubling would yield-if
not quite as good as full-resolution progressive images. Image
degradation is hardly noticeable on most real-world subjects, and
most NLEs now handle 24F and 30F modes natively. "

Full article at <http://www.dv.com/reviews/reviews_item.php?articleId=196602584>

[Daniel Patton]

That aricle was perfect, thanks Dick.