Multiple questions on the Flash XDR
 

Mike et al.,

First, congratulations on what is shaping up to be an excellent product!

I'm currently in the process of outfitting a commercial production house from scratch, and the Flash DXR answered a whole mess of questions I had about my workflow. ;)

Naturally, I still have some more. In founding this business, I'm having to wear a whole lot of hats I'm not specifically used to. For example, I'm not a Technical Director, yet I have to make decisions on relatively expensive equipment purchases, and while I've done some amateur editing, I'm by no means an editor. But more on that later...

The first three questions are specifically for Convergent Designs. The next three are related, but not specific to, the XDR, and I'm hoping with the vast level of technical knowledge this thread attracts even if Mike and the CD guys can't answer them, someone else here can.

Here we go:

1.) I believe this one was answered, but just for clarification... the Flash XDR can be configured to simultaneously record redundantly to two CF cards, correct? (RAID 1, I think it's called?)

2.) If yes, I know I have the option of recording either .xmf or quicktime, but can I do both at the same time? Specifically, would it be possible to shoot some footage, record it simultaneously to two CF cards, then pull those two cards out and hand one to the producer/director for instant Quicktime viewing via QT player on a laptop, and send the other to the editor for .xmf editing on the NLE?

3.) In order to record via HD-SDI from the Sony EX3, I apparently have to have an SxS card in the camera. Mike Schell said somewhere that all you have to do is record to both the SxS and the Flash XDR at the same time. Is that even possible? I thought the whole point of the XDR was that you _can't_ record 50mbps 4:2:2 natively in the EX1/3. Do you basically end up with two separate formats of footage, one at 35 4:2:0 and one at 50 4:2:2? I guess I need a little clarification on the whole CF/SxS simultaneous thing.

4) Just double checking - I'm purchasing all the equipment around Sept. (conveniently, the same time that the DXR comes out). Will the copy of FC Studio 2 I buy then be able to edit 50mbps 4:2:2 at that point? If not, do we have a time-frame when FCP will support this?

5) Will a 3.0gb dual quad core Mac Pro with 8gb of ram and a good video card be able to edit 50mbps 4:2:2 footage in real time? Again, I'm not an editor by trade so I'm just buying an insanely powerful computer in the hopes that my editor will have the tools he needs to edit my footage. I have no practical knowledge of what kind of computer is needed to edit HD.

6) From a technical standpoint, can anyone see any flaws in the following setup? As I'm trying to identify the equipment I intend to purchase, I have no practical way of knowing whether or not it will all work together the way I want it to - so I either have to ask or plug everything in and hope for the best (after the money is spent). The setup looks like this:

Sony PMW-EX3 <--HD-SDI--> LS Carrion B (or C) Monitor <--HD-SDI--> Flash XDR <--XLR--> Azden mixer <--XLR--> shotgun mic.

This setup is an attempt to utilize the Flash XDR's ability to record both higher quality video and audio than what the camera can natively. I guess what I'm asking is, will the monitor mess with the signal to the Flash XDR? Will the mixer somehow prevent me from recording 24bit sound?

Phew! I guess the problem with dvinfo's process of approving members is that while I'm waiting for my application to be approved, I think up even more questions to ask. I sincerely appreciate the efforts of anyone who takes the time to actually read all this, and I am especially grateful to those gracious enough to provide answers.

-Jeff

I'll take a stab at answering a couple of your questions:

1. Yes the XDR will record in a redundant Raid setup

5. The Mac you note will be able to edit the format noted in real-time for simple cuts. But I would not expect effects and color correction to all work in real-time - there will be rendering involved. I have the same system you note but have not edited 50mb 4:2:2 on it as of yet. I make this guess about real-time based upon less data intensive edits and the effect of these heavier files.

This hasn't been listed in the specs and I doubt it's going to happen for a while since writing two files at the same times is probably not a quick code change. It's probably easier to have a utility/plug-in like Raylight to re-wrap the mxf.




You don't need a card to record as the SDI is live all the time. If you want the XDR to automatically start recording when it detects incremental timecode, then you need a card so you can hit 'record' on the camera. If you're OK with hitting record on the XDR, no card is needed.

The second copy on the SxS would be standard EXCAM, not 50/100 4:2:2.




50/100 4:2:2 isn't currently included in the FCP distribution, but it doesn't need to be. All you'll need is the quicktime codec that will be installed separately. The codec will enable all Quicktime apps, not just FCP, to use 50/100 4:2:2.



Yes it will, but your editor will have a significantly better experience if you transcode your footage to Prores.




It's a digital signal, so you shouldn't have an issue, but you'll know instantly. It won't degrade the signal, it will either work or not work. I personally would run the SDI to the XDR first, and then loop through to the monitor.



The signal is still analog at the mixer out, so it's fine.

Fantastic idea! It has the added benefit of allowing me to monitor what I'm recording, and not just what the camera is sending out.

Many thanks to the both of you for tackling my questions. As for the editing computer suggestions, the editor I'm working with is a pro and an industry vet. I'm sure he'll know the best ways of working with the footage (ProRes, etc.), I just wanted to make sure I was providing him with a machine that is up to the task.

Sincerest gratitude,

-Jeff

I work with 50 4:2:2 in FCP with no issues. I simply import the clips via Sony's XDCAM Transfer utility and life is good. If you forget to properly set your project settings, when you lay your first clip into the timeline sequence, the sequence will adjust to your clip if you desire.

I am curious, why would my editing experience experience be better first transcoding my native source to ProRes? Also, does anyone know what the QT codec for the Flash units will be? My guess is ProRes.

David Schmerin

ProRes is an intraframe codec so you eliminate all long GOP issues. ProRes also performs significantly better than any other codec inside of FCP. You can preview at higher quality, you can run more concurrent streams, you can do more real time effects.

ProRes HQ is a 10 bit codec, so you have more color space room for additional effects and transitions than you have in the 8 bit color space of the native codec.


The chip in the Flash is a Sony chip, so it's Sony MPEG2 4:2:2 in either long GOP at 50/100 Mbps or I-Frame at 100/160 Mbps.

Quicktime, like MXF, is a container, not a codec, so the QT movies will be one of the above codecs.

Generating ProRes422 would be a dream, but nobody makes a ProRes encoder chip, and the horsepower required to encoded ProRes isn't going to be inside a low power/size box like the XDR/Nano anytime soon.

But there is the AJA Io HD that supports ProRes HQ in hardware, making it possible to capture to a MBP.

I agree that power and size are issues that impede HQ codecs (ProRes, Cineform) to be used in small devices. The Io HD + MBP still requires AC power as does the Wafian field recorder and neither option is really 'small' (but portable).

I'm also following FFV's Elite. They seem to be close to release (at IBC) and record HD SDI to disk in 10bit J2K (JPEG2000, non-GOP) at 100Mb/s in 4:2:2. Don't seem to support 1080p though.

George/

I believe Grass Valley's Edius will also support the Sony Mpeg2 50 4:2:2.

Hi Jeff & Everyone-
I think most of your questions have already been well answered. I would add just a few additional comments:

1) While you will be able to record the same footage to two cards simultaneously (RAID1), both files must be the same format (QT or MXF). Writing two different formats simultaneously would be very difficult.

2) I would try editing in native MPEG2 4:2:2 initially and later compare to ProRes. It think there are merits to both approaches. After the transcode, the ProRes will respond faster, as Apple optimized this CODEC for maximum performance. However, with a very fast processor, you may find the native MPEG2 more than acceptable.

3) ProRes and DNxHD hardware CODECs tend to be quite power hungry and generate a fair bit of heat, both of which you want to avoid in a portable recorder/player. They are also not nearly as efficient as MPEG2 since they only employ I-Frame compression. The MPEG2 CODEC in Flash XDR only requires 3W of power and produces excellent quality video at only 50 Mbps. I seriously doubt that any other hardware CODEC can can offer high-quality video at low bit-rates coupled with low power consumption.

4) We seriously looked at the JPEG2K CODEC for quite some time. It does offer 10-bit processing, but it has a significant drawback with regard to playback performance. All reports indicate that a high-end laptop can barely playback one stream of J2K footage, thus forcing a transcode, even to view the video. J2K is also much less efficient than MPEG2 since it also does not utilize temporal compression (P,B frames).

Every design involves many compromises. We have chosen a design path which emphasizes small-size, lightweight, low-power, all solid-state, with excellent quality video on low-cost media supporting a tapeless workflow.

Even Tompson Grass Valley whose Infinity camera was developed to shoot in Motion Jpeg2000 has a tough time handling more than one stream with their own NLE Edius. As Mike noted it is a very computer processor power intensive format - but very high in quality from what I have seen in demos.

It takes a computer with a great deal of grunt to handle minimal streams and minor effects. Many people transcode it to their codec version of ProRes named HQ. HQ is intra-frame and looks great.

Link to a hardware Motion Jpeg2000 encoder accelerator:

http://www.dv.com/news/news_item.php...leId=196604225