Forums > Jitter

HDV camcorder options and latency

March 5, 2007 | 3:41 am

Dear Jitter people,

I’m needing to buy an HDV camcorder which I would like, amongst other things, to work well with Jitter in real-time. I’m considering the Sony FX7 (for it’s ease of use) but also the Canon XH-A1 (for it’s progressive scan/frame mode). Both have SD 480 out but the Sony is i(which I’d prefer) I will have to de-interlace the image by either running it through some Jitter objects to "throw out every other frame and up-sample" or run the camera’s analog out through some kind of hardware like the DFG-1394A.

My question is, which method would have the least latency and roughly how much latency would that be over using the Canon’s frame mode?

Thanks in advance for any light shed on this subject,

Christopher


March 5, 2007 | 4:47 am

You could use actual HD out with jitter instead of SD–
see previous threads regarding HDMI output and the Decklink.com
Intensity card.

-deKam

>
> Dear Jitter people,
>
> I’m needing to buy an HDV camcorder which I would like, amongst
> other things, to work well with Jitter in real-time. I’m
> considering the Sony FX7 (for it’s ease of use) but also the Canon
> XH-A1 (for it’s progressive scan/frame mode). Both have SD 480 out
> but the Sony is i(which I’d prefer) I will have to de-interlace the
> image by either running it through some Jitter objects to "throw
> out every other frame and up-sample" or run the camera’s analog out
> through some kind of hardware like the DFG-1394A.
>
> My question is, which method would have the least latency and
> roughly how much latency would that be over using the Canon’s frame
> mode?
>
> Thanks in advance for any light shed on this subject,


March 5, 2007 | 5:28 am

Thanks deKam, I did see that post, but that’s kind of what I meant about using "some kind of hardware". It looks like a great solution but not when I’m using my Mac Book Pro :-)

BTW I see part of my post got cut off. It should read:

"Both have SD 480 out but the Sony is interlaced. If I understand the previous posts, if I go for the FX7 I will have to de-interlace the image by…"

Cheers,

Christopher


March 5, 2007 | 6:19 am

sorry, i got caught up wondering why you would want to buy an HD
camera for SD input

btw
If i were buying a camera for pure image quality (for the money) in
the SD realm, I would get a used Canon L2 — http://cgi.ebay.com/
Canon-L2-Video-Camera-and-
accessories_W0QQitemZ160090069449QQihZ006QQcategoryZ15075QQssPageNameZWD
VWQQrdZ1QQcmdZViewItem?hash=item160090069449

imho we’ve gotten all too accustomed to DV, and compression. but
enough ranting :)

The DFG-1394 wins hands down as the lowest latency digitizer vs
firewire dv

The only other box that comes to mind, and much higher quality:
http://aja.com/html/products_Io.html it works uncompressed over
firewire, though i can’t speak for its latency, but assuming
uncompressed = low latency it should be great.

deinterlacing on the fly in software is trivial, i wouldn’t worry
about it in your camera decision. an old broadcast video sage once
told me, when it comes to cameras, the primary thing to consider is
‘the glass’

-deKam

> Thanks deKam, I did see that post, but that’s kind of what I meant
> about using "some kind of hardware". It looks like a great solution
> but not when I’m using my Mac Book Pro :-)
>
> BTW I see part of my post got cut off. It should read:
>
> "Both have SD 480 out but the Sony is interlaced. If I understand
> the previous posts, if I go for the FX7 I will have to de-interlace
> the image by…"


March 5, 2007 | 6:26 am

4 frame latency with Final Cut Pro and 10.4. 7 frames with 10.3. Ive
never tried one with Jitter though. I might be able to test tomorrow …

On Mar 5, 2007, at 1:19 AM, dekam wrote:

> sorry, i got caught up wondering why you would want to buy an HD
> camera for SD input
>
> btw
> If i were buying a camera for pure image quality (for the money) in
> the SD realm, I would get a used Canon L2 — http://cgi.ebay.com/
> Canon-L2-Video-Camera-and-
> accessories_W0QQitemZ160090069449QQihZ006QQcategoryZ15075QQssPageNameZ
> WDVWQQrdZ1QQcmdZViewItem?hash=item160090069449
>
> imho we’ve gotten all too accustomed to DV, and compression. but
> enough ranting :)
>
> The DFG-1394 wins hands down as the lowest latency digitizer vs
> firewire dv
>
> The only other box that comes to mind, and much higher quality:
> http://aja.com/html/products_Io.html it works uncompressed over
> firewire, though i can’t speak for its latency, but assuming
> uncompressed = low latency it should be great.
>
> deinterlacing on the fly in software is trivial, i wouldn’t worry
> about it in your camera decision. an old broadcast video sage once
> told me, when it comes to cameras, the primary thing to consider is
> ‘the glass’
>
> -deKam
>
>
>
>> Thanks deKam, I did see that post, but that’s kind of what I meant
>> about using "some kind of hardware". It looks like a great
>> solution but not when I’m using my Mac Book Pro :-)
>>
>> BTW I see part of my post got cut off. It should read:
>>
>> "Both have SD 480 out but the Sony is interlaced. If I understand
>> the previous posts, if I go for the FX7 I will have to de-
>> interlace the image by…"
>

v a d e //

http://www.vade.info
abstrakt.vade.info


March 5, 2007 | 7:54 am

> sorry, i got caught up wondering why you would want to buy an HD
> camera for SD input

Dual use: I’d like a camera that I can use to shoot beautiful HD images with a minimum of hassle, run it through FCP and then non-real-time Jitter, but that will also output uncompressed SD for live stage use with low latency. So if the FX7 will cost me in terms of latency deinterlacing then I’d get the ZH-A1.

>
> The only other box that comes to mind, and much higher quality:
> http://aja.com/html/products_Io.html

I’ll check it out!

> deinterlacing on the fly in software is trivial, i wouldn’t worry
> about it in your camera decision.

That’s great to know, thanks.

Christopher


March 5, 2007 | 10:37 pm

vade, how do you check latency? clapping hands make me look stupied

On 3/5/07, Christopher Keyes wrote:
>
>
> > sorry, i got caught up wondering why you would want to buy an HD
> > camera for SD input
>
> Dual use: I’d like a camera that I can use to shoot beautiful HD images
> with a minimum of hassle, run it through FCP and then non-real-time Jitter,
> but that will also output uncompressed SD for live stage use with low
> latency. So if the FX7 will cost me in terms of latency deinterlacing then
> I’d get the ZH-A1.
>
> >
> > The only other box that comes to mind, and much higher quality:
> > http://aja.com/html/products_Io.html
>
> I’ll check it out!
>
> > deinterlacing on the fly in software is trivial, i wouldn’t worry
> > about it in your camera decision.
>
> That’s great to know, thanks.
>
> Christopher
>


March 5, 2007 | 10:51 pm

google ’2 beep’ or ‘two beep’

typically for post production you run bars and tone, a slate with a
countdown, and then, at the second (2nd) second before picture, you
beep for one frame right at 00:59:58:00, picture rolls at even hour,
01:00:00:00

measure the frame difference from the 2beep to when you see it, thats
your latency, basically. The only reason I knew it was 4 and 7 frames
respectively was because Ive set up and installed those systems with
final cut, and spoken to AJA way too many times. Apple fixed
something in 10.4 that lowered the latency by 3 frames. *shrug*

On Mar 5, 2007, at 5:37 PM, yair reshef wrote:

> vade, how do you check latency? clapping hands make me look stupied
>
> On 3/5/07, Christopher Keyes wrote:
>
> > sorry, i got caught up wondering why you would want to buy an HD
> > camera for SD input
>
> Dual use: I’d like a camera that I can use to shoot beautiful HD
> images with a minimum of hassle, run it through FCP and then non-
> real-time Jitter, but that will also output uncompressed SD for
> live stage use with low latency. So if the FX7 will cost me in
> terms of latency deinterlacing then I’d get the ZH-A1.
>
> >
> > The only other box that comes to mind, and much higher quality:
> > http://aja.com/html/products_Io.html
>
> I’ll check it out!
>
> > deinterlacing on the fly in software is trivial, i wouldn’t worry
> > about it in your camera decision.
>
> That’s great to know, thanks.
>
> Christopher
>

v a d e //

http://www.vade.info
abstrakt.vade.info


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