XL-H1 uncompressed hd video

S

senseid

New member
i wonder if anybody can tell what is meant by "The XL H1 also features uncompressed HD-SDI (SMPTE 292M)" from the Canon XL-H1 description. And how would you record uncompressed Hi-Def coming out of the XL-H1. I have a client that thinks he hired a Hi-Def crew (DVCPROHD) when all they are using are XL-H1's which is HDV.
Just curious. I haven't got any experience with that camcorder yet, and need to find out.

Thanks
 
The HDSDI output on the canon puts out 4:2:2 1920x1080 uncompressed HD footage (I believe those are the correct numbers). I also believe it averages around 3 gigabits/s. You can capture it to a RAID using cards that Blackmagic or AJA produce. It is really only viable in studio circumstances.
 
Even then, recording the XLH1's HD-SDI has other challenges, which include that it doesn't embed audio nor timecode in the data stream. If one wanted to record the HD-SDI signal they'd perhaps be better off by trying to record the XHG1's HD-SDI; the G1 added timecode and audio to the HD-SDI data stream.

It's not practical to go recording 1.5 gigabits per second; it's an extremely huge data rate. But as William said, if you're gonna do it, it's really only practical in a studio environment.
 
Senseid,

Barry's right, true uncompressed is impractical for most in-the-field situations, but things are changing a bit.

Truth is, you don't really need uncompressed. What you probably want is to acquire in a full-res codec that is nearly lossless and maintains the full 4:2:2 colorspace of the raw HD-SDI signal. For this end, I'd recommend looking into the AJA I/O HD which would allow you to record through HD-SDI to the new Apple ProRes codec (if FCP is an option) direct to a laptop via Firewire 800. The box can take the timecode output from the H1 and you can record audio direct to the I/O HD rather than through the H1. As a nice little bonus, you can record HDV simultaneously for a safety backup.

This would of course require a capture technician on-set, but physically, the hassle of lugging a laptop and small box around is not such a big deal.
 
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Would you recommend for us to shoot uncompressed if the final material is to be transferred to film? Or is there another workaround that maximises the integrity of the footage prior to any editing?

Derrick
 
I'd recommend it.

It'll give you more room to grade your footage in post and will cause a slightly better looking final product.

It's one of those things that the average person would never notice but filmmakers may notice a slight difference.
 
Hi,
Thanks for the reply.
I know going into a DVCPROHD deck via hd-sdi isn't exactly uncompressed, but given the similarity in luma and chroma sampling (4:2:2), would this be a good alternative to ingesting uncompress straight into HDD?
 
I'm not positive that you can do that without an intermediate.

If you can though, it should be similar to uncompressed. I think your best bet would be to go with what Elton recommended.
 
Well, with just about every prosumer high definition camera you can record uncompressed video via component cables.

And although the output is 1920x1080, it's interpolated from 1440x1080 which is native to the camera's sensors.
 
Elton said:
Senseid,

Barry's right, true uncompressed is impractical for most in-the-field situations, but things are changing a bit.

Truth is, you don't really need uncompressed. What you probably want is to acquire in a full-res codec that is nearly lossless and maintains the full 4:2:2 colorspace of the raw HD-SDI signal. For this end, I'd recommend looking into the AJA I/O HD which would allow you to record through HD-SDI to the new Apple ProRes codec (if FCP is an option) direct to a laptop via Firewire 800. The box can take the timecode output from the H1 and you can record audio direct to the I/O HD rather than through the H1. As a nice little bonus, you can record HDV simultaneously for a safety backup.

This would of course require a capture technician on-set, but physically, the hassle of lugging a laptop and small box around is not such a big deal.
Click to expand...

All you need to do is take the HDSDI output and plug it into a Sony HDCAM field recorder and you'll get either 24 F with 3:2 pulldown or 29.97. You'll need to do dual system audio since the HDSDI output doesn't carry audio.

M
 
Elton has it right. Apple's new mastering codec "ProRes 422 HQ" is the almost exact equivelant of Avid's DNxHD codec. The DNxHD codec is used to master almost every theatrical movie trailer produced these days. All these trailers get printed to 35mm film for release into theaters.

I'm currently finishing post-production on a feature film shot entirely with the H1 and recorded straight to hard disk using the ProRes codec. I couldn't be happier with the results. The data is completely manageable, the quality is superb, and the FCP > Color > FCP workflow works very very well.
 
Mark Pedersen said:
All you need to do is take the HDSDI output and plug it into a Sony HDCAM field recorder and you'll get either 24 F with 3:2 pulldown or 29.97. You'll need to do dual system audio since the HDSDI output doesn't carry audio.

M
Click to expand...

Hi Mark-
Have you seen the Flash XDR from Convergent Design? We can record HD-SDI out of the Canon XL-H1 onto Compact Flash cards using the high-quality hardware CODEC from Sony. We can record in a number of different bit-rates, including 100 Mbps 4:2:2 Long-GOP and 160 Mbps 4:2:2 I-Frame only. Both of these formats are full-raster (1920x1080). You can download comparison images from our website (www.convergent-design.com). Either of these rates are far above HDV and better than DVCProHD or even HDCAM. All of this in a portable battery powered box.

We'll have a firmware update for uncompressed coming this fall.

Mike Schell
Convergent Design
 
This would've been the ideal solution for our film shoot last August. To me this seems to be the best way to go. You've got the portability similar to a Focus drive, but the quality of I-frame 4:2:2 compression.

Can't wait to actually get to play with on these puppies.
 
Robert Sanders said:
This would've been the ideal solution for our film shoot last August. To me this seems to be the best way to go. You've got the portability similar to a Focus drive, but the quality of I-frame 4:2:2 compression.

Can't wait to actually get to play with on these puppies.
Click to expand...

Hi Robert-
I can assure you that the 160 Mbps 4:2:2 full-raster (1920x1080) I-Frame only is considerably above HDV quality and virtually indistinguishable from uncompressed.

BTW, we're using an XL-H1 for our testing. Great camera.

Mike Schell
Convergent Design

PS We were in the Canon booth at NAB. We also picked up two awards at the show.
 
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