Ask Bob and then stand back
COW Library : Adobe After Effects Techniques : Bob Zelin : Ask Bob and then stand back
HEY BOB, TO SCOPE OR NOT TO SCOPE?
I come from a background of edit rooms that 100% had scopes in them. Today, most of my clients have no scopes. And many TV stations, particularly local stations, don't care what you send them. They want the advertising revenue, and won't reject anyone's tapes. They own their own proc amps and legalizers, so they accept anything they can.
But crazies like Discovery and PBS will reject anything they can. It's for companies like these that you must have calibrated scopes, or your master delivery tapes will get rejected, and your clients will kill you.
Will SD scopes work just as well for HD video on a down-converted signal? My normal answer would be no, especially because your Videotek composite scope probably hasn't been calibrated in 20 years. But looking at a real scope, even in down-converted composite, is better than looking at nothing.
This is the final answer: if your master tapes get rejected, then guess what? You needed a scope. If your tapes go on air, then forget everything I just said.
HEY BOB, WHY DO YOU KEEP TELLING ME NOT TO WORK IN 24P?
24p is a generic term. In practice, it generally means 23.98. The exceptions to this are certain cameras that can shoot at true 24, and are used in DI work to print back to film. In the wonderful world of video though, nearly everyone uses 23.98. Unless you are named George Lucas, the odds of you needing to work at 24 are slim. Burn the number 23.98 into your head.
But do you really need to work in 23.98? If you are just doing a simple TV show, where you are using 23.98 field tapes to output at 29.97 or 59.94, make it easy on yourself. It is very common to shoot at 23.98, and use the 2:3 pull-down feature in the VTR to feed into your editing system at the broadcast frame rate. Easy!
There are those across the Cow that insist that if you shoot at 23.98, you should edit at 23.98. Do the pull-down conversion only when going out of your edit system back to tape. But I am telling you that almost 100% of my clients DO NOT DO THIS. They allow the deck to do the 2:3 pulldown on the way in, and edit at broadcast frame rates.
Even less-expensive HD products like those in the HDV line automatically insert the pulldown. All professional VTRs today offer pulldown cards - either for free or as an option. You can even go with products from AJA and Blackmagic that add the pulldown during digitizing.
But you say you want to work in 23.98 anyway! Your camera can do it, you want a film look - so why not? If all your footage is 23.98 (like P2), and you get to deliver in 23.98 - say, to DVD - this is great.
But you better hope you don't have to mix in 1080i/30 or 60 footage (that is, 29.97 or 59.94) or upconverted SD. None of those are 23.98 native. If you try to mix them, you're in for big trouble.
Rather than burn in render hell, burn "edit at broadcast framerates for broadcast output" into your brain. Make it easy on yourself. Insert pull-down on the way into your edit system.
And to keep my reputation as "Blackburst Bob," the law requires that I tell you: if you are forced to work in 23.98, and need to output to tape at 23.98, you MUST use a tri-level sync generator to genlock your edit system to your VTR. It's the law!
Certainly, you can use one of the traditional trilevel sync generators from Evertz, Tektronix, NVision, etc. - but with new, inexpensive tri-level sync generators from both AJA and Blackmagic that can do both SD black and tri-level sync, there is no longer any excuse to say "I can't afford a tri-level sync generator." They should be passing out AJA GEN10s at birth.
HEY BOB, DOES THE NEW DIGITAL BROADCAST STANDARD AFFECT DELIVERABLES?
The digital broadcast requirement is just that. SOURCE material can remain all analog, as long as the signal being BROADCAST is digital. Which means if a broadcaster puts an AJA FS-1 or similar product from Cobalt Digital, Miranda, Evertz, etc. just before transmission, they are now a digital station.
It's got nothing to do with the footage they're actually working with. People will continue to send in their VHS tapes to Americas Funniest Home Videos. And those tapes will continue to be aired alongside BetaSP, U-matic and all the crap that's airing today - as long as it gets frame-synced and converted to SDI before it hits the transmitter.
However, many stations will become more stringent than ever. For these guys, delivery requirements mean much more than just watching your "white" levels. There are pages of documentation that must be adhered to that varies with each broadcaster.
For example, Discovery requires Sony SRW-5500 delivery, with 8 discreet channels of embedded audio. AND they demand that audio be monitored by a Dolby LM-100 audio meter. Now, I only have one client that owns even one of these. I have no idea of how Discovery can tell if anyone owns them, but that's the specification.
But maybe your station wants BetaSP. ("But I shot my show in HD, how can I deliver a beta tape?") Some require DigiBeta, or HDCam, or DVCProHD, or D5. More and more require Sony HDCam SR. ("But that machine costs $1200 a day to rent!")
Blackmagic HDLink Pro
What does all this mean? It means that it's YOUR JOB to call every broadcaster that your client wants you to deliver to, and find out what their delivery specs are, because each one has dramatically different delivery requirements than the next.
Is this a pain in the ass? You bet it is!
You ask, "Why can't I just deliver my HD master on a FireWire drive, and let them transfer it to any darn format they want?" Because that's not how the game is played. It's gonna be your aggravation and your money (hopefully reimbursed by your clients) to make the broadcaster happy.
"I just want to know what to do so I'm not driven crazy by all these different broadcasters!" This is the answer: you will be driven crazy for THE REST OF YOUR CAREER. I've been doing video engineering since the stone age (linear editing in the 70s). "Nothing" is good enough, nothing that you do is "broadcast quality" according to those that want to torment you.
You can go out and buy a HD scope for $12,000 tomorrow, and the station will reject your tape because "Final Cut Pro overwrote line 21 of the vertical blanking interval, and we can't read the closed captioning information."
The only place you can avoid this is on YouTube, but wait.. As web video becomes more mainstream - and God forbid, regulated - there will be delivery requirements, and there will be a whole new set of rules that you and I don't understand, and that will have to be met anyway.
It's never over.
HEY BOB! SHOULD I BE USING RAID 0 OR RAID 5? AND HEY, WHAT'S RAID?
When you see "dropped frame" errors in Final Cut Pro, or "Video Underrun" in Avid systems, it's time for faster storage. A proven method for improving performance is to "stripe" multiple disk drives together, formatting them so that they work in unison.
Striping creates a Redundant Array of Independent Disks (RAID). Software to do this is provided for free by both Microsoft (Microsoft Disk Manager), and Apple (Apple Disk Utility).
But these create RAID O striping. The multiple disk drives will work in unison for better performance, but there is no protection in case one of the disk drives fails.
If just one of the disk drives fails, you lose ALL of your media from ALL of your disk drives. This is very frustrating, and totally unacceptable.
So RAID 5 - and variations of this like RAID 3 and RAID 6 - were developed to ensure that if a disk drive fails, you do not lose everything. RAID 5 "sprays" the redundant compressed data among all the disk drives. If one of them fails, the "backup data" is spread around the other disk drives.
When you insert a replacement drive into your RAID 5 array, the data is rebuilt from the compressed information. Now you once again not only have your original information, but your backup system is now in place once again.
RAID 3 uses a single disk drive, called a parity drive, to store the backed-up compressed data. RAID 6 allows for TWO disk drives to fail without losing your media.
So what about RAID 0? It's cheap. It's easy. It will work wonderfully, and if you are lucky - IF YOU ARE LUCKY - it will keep working. But if one drive fails, you will lose ALL OF YOUR MEDIA.
What will happen next is that you will come to the Cow and say, "My RAID failed, now I can't see any of my media." And what will happen after that is that I will say, "I TOLD YOU SO!!"
You have been warned.
HEY BOB! I WANT TO WORK IN 2K, BUT I DON'T WANT TO SPEND THE KIND OF MONEY IT TAKES TO WORK IN 2K. WHAT SHOULD I DO?
Cheap 2K?!? I ought to take you out back and give you a whuppin'. Who ever heard of such a thing?
Of course, just wait until the Scarlet comes out next year. Everyone with $6000 ($3K each for camera and lens) will want to edit like it's DV on a FireWire drive. As it is today, people without a lot of money that want to do HD usually start with HDV, or P2 or Sony XDCAM, and work in heavily compressed 720p or 1080i, maybe on a laptop or iMac. (Hey, it's got a 24- inch screen. Why not?)
Now YOU want to do 2K, because 1080i with the ProRes422HQ codec or Avid DnxHD is not good enough for you. (You know the Olympics came to you with Avid DnxHD 120, right?) No, you want 2K, you want it now, and you want it cheap.
Well, 2K and 4K workflow will continue to develop, so that anyone can do it, with no knowledge, no workflow issues, and almost no equipment. For now, start with a Blackmagic Decklink HD Extreme or AJA Kona 3 for I/O.
I used to be one of the idiots that said, "And you definitely have to buy an HD monitor." Then along comes Blackmagic's HDLink Pro, so you can see a 2K image file on an Apple 30" Cinema display. You should be kissing Blackmagic's behind for this.
The drive array will be the most expensive part of your investment. Make it RAID 5 so you don't lose any of your media, and so I don't have to get in my car to say "I told you so!" in person. But it also needs to be fast enough to sustain 500MB/sec. Want a couple of streams of real time? Double that.
And the array needs to be big. Those 2K RAW files will eat up your drive space like crazy, around 720GB/ hr. Even if you offline at DV25, you want to conform at 2K, right? You're still looking at 2TB before you finish effects, color grade, etc. - and those are going to fill up even more drive space.
If you want to "future proof" your "cheap" 2K system for when you want 4K next month, quadruple all of the above. (No, not double. Quadruple.)
So unless you're building an offline system, and will conform at a post house, THERE AINT NO CHEAPO 2K WORKFLOW.
And if I am wrong, and you successfully find a way to charge $400 a day to conform 2K jobs, well, you will have to be punished. That's all there is to it.
Have your own questions that you'd like to ASK BOB? Then write us at magazine at creative cow dot net and tell us what you'd like to ASK BOB. Oh, and if you are one of those that ignores his answer, remember, he will tell you that he told you so. Consider yourself warned.
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