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Advantages of IO HD for P2 Cameras?

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joe hedge
Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 4:58:24 am


Bit of a noobie question..what would be the advantages (if any) of using an IO HD with a HVX200 camera? If the media is already recorded to the P2 cards in DVCProHD, for instance, can the IO transcode in real-time, or faster, the media to ProRes, and what would be the advantage of that? Or would the only advantage be in recording/transcoding straight to external drives from the live camera feed?




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Carsten Orlt
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 6:27:04 am

ok what is the ioHD?
It is basically a mobile capture card with all the analogue-digital converters build in.
Only way for Apple-Aja to make this work in HD (they already did it for SD with the io) was to build the device around ProRes. So the signal send through the firewire is the raw ProRes data that is converted by the chip build of the ioHD into normal video signals.

For you to use the DVCProHD codec from your P2 card the computer has to transcode the DVCProHD data from the timeline in realtime to ProRes data to send to the ioHD. For you to be able to do that you need quite a beefy CPU, speak MacPro or latest MacBookPro's.

The question you really have to answer is the following:
Do I want to be A. mobile and/or B. do I want a device that I can connect to any future CPU (at least for a few years..io's are still working!)?
If either or both answers is/are yes, then the ioHD is a good choice, BUT everything HD will basically need to be ProRes for you to really enjoy the box. Yes it can playback DVCProHD with the right CPU, but its not build for that. The better workflow is to capture or transcode to ProRes on ingest.

If you have a MacPro the Kona range might be the better choice if you didn't answer yes to question A and/or! B.

Beside my funny english, I hope this will give you some food for thought.
Cheers






Carsten


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joe hedge
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 7:16:53 am


"The better workflow is to capture or transcode to ProRes on ingest."

So that means sending the live feed directly through the IO HD to the CPU (and external storage), bypassing the P2 cards and/or Firestore device? What I'm wondering is if the IO will essentially just act as a P2 card reader while transcoding to PR422, or do I have to follow the workflow you described of "the computer has to transcode the DVCProHD data from the timeline in realtime to ProRes data to send to the ioHD."




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Carsten Orlt
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 10:37:38 am

when you connect the camera directly to the ioHD you are not transcoding anything.
you are encoding the video signal from the camera straight to ProRes. No DVCProHD involved.
Only when you go to P2 you create DVCPro Hd files which, when not transcoded 'manually' to ProRes before playback (e.g. convert using Compressor), will need to be transcoded on the fly by the CPU before being send to the ioHD.

I think what you're really asking is: I want to record a live event. Is it better to record in the camera to P2 or better to feed the camera into the ioHD and capture ProRes this way.

Hm. I haven't tried that (Jeremy) so not sure if the quality of the signal would be the same? One is handled internally by the camera, the other will need to be converted to a video signal (camera) and then encoded into ProRes (ioHD).

And just thinking: You can't connect the camera via Firewire and the ioHD via Firewire at the same time...

Sorry wasn't sure what you were after :-)

Cheers

Carsten


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gary adcock
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 3:15:13 pm

[Carsten Orlt] "I haven't tried that (Jeremy) so not sure if the quality of the signal would be the same?"

live capture of your video over component would be better than the DVCPROHD as recorded in camera.

The component signal is 10bit 4:2:2 full raster format while DVCPROHD is always an 8bit "thin raster" (horizontally compressed).


That being said

- does the need for higher quality offset the the added additional expense, hardware and hassle?


The IoHD works great with P2 materials on desktop configurations. Most laptops are still lacking processing required to do the needed transcode from P2 to ProRes in realtime as needed by the IoHD.



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD




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joe hedge
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 5:14:31 pm


Thanks for the replies. I return to my original question - what would be the advantage (if any) of using an IO HD with a P2 camera



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Jeremy Garchow
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 6:54:45 pm

I think you're questions have been answered, but if you want to capture straight to ProRes via component and ioHD, you will get a better picture than by going to p2 cards. Very helpful for green screen sessions.

If that isn't an option, I'd suggesting logging and transferring the p2 media, then transcoding all of that through compressor to ProRes for easier ioHD editing. I wish log and transfer would encode to ProRes as it does for AVC-I and other material, but alas it does not.


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Michael Sacci
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 7:00:59 pm

Gary pretty much answered that question. IF you tether the camera's component analog out you can capture with the IoHD in ProRes. But this is really only useful when you can lock down the camera for this type of setup. But this is bypassing P2 altogether (of course you can be recording to P2 at the same time, but there is no TC going from the camera to the Io.

The most use of the IoHD will be after you ingest the P2, you can set up a external monitoring with both HD and SD at the same time. Then mastering out to tape you have all the options to go to just about any deck/format needed. (no 4:4:4).

Most people with the HVX need to evaluate this purchase on the post side of life and probably not production/capture.

I will say one place where the tethered capture make a lot of sense is for green screen. To capture that with 10-bit ProRes would be worth any setup time you had to go through.

But a question that might be under the surface here. Does the IoHD help transcode DVCProHD to ProRes after the capture. The IoHD does nothing to help with computer based transcoding. If you log/transfer P2 to DVCProHD the IoHD will not help to convert that footage to ProRes in any way... Unless you have to systems and playout the DVCProHD on one and capture to the other in ProRes. I do this all the time for Downconverting and upconverting.But with doing it this way the compression and lack of color space is already there.



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joe hedge
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 7:32:32 pm

Thanks for the patient replies, bear i mind I'm a noob here trying to figure things out



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David Perry
Re: Advantages of IO HD for P2 Cameras?
on Sep 9, 2008 at 9:51:08 pm

For me the reason I use the IOHD is to take a live HD switch of 4 HVX200 cameras and get a great ProRes HQ picture. This works especially well for a live cut of a long event and then use P2 cards, Firestore or Citidisk to record the ISO on the separate cameras. However, if I am just using one camera on a job I would not bother with the extra equipment as DVCpro HD is fine for most everything else.

David Perry
Carmen Productions


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