High Def 25Psf video

More than a decade ago when Mr Sony was developing what would become HDCam (with some small contribution from the previous 1" open-reel HDVRS analogue & digital formats) they realised that progressive video was the future but existing HD equipment (typically the BVM-D series monitors) couldn't lock to such a slow framerate (24/25/29.97 as opposed to 48/50/59.98 fields). The answer for progressively-sourced pictures was the Psf standard which makes progressive frames look like interlaced video. So as to make film people think that this was better than video they have a new name for a field - the segment. In fact Psf is interlaced video (but there is no movement between the fields) - it just shows that good old interlaced video is able to faithfully reproduce progressive pictures (but the reverse is not true as progressive video with the same frame-rate has only half the motion rendition as interlaced video).

So - let's dismiss a couple of misconceptions;

• There is no difference between a Psf signal and an interlaced signal from a technical standpoint
  
• Sending 1080 pictures via Psf doesn't degrade them in the slightest - in fact if you're laying off 1080 to HDCamSR then anything below a 5800 (in 50/60P mode @880mBits) is recording Psf!

Now then - below are screen-grabs from my trusty WFM7120. The first shows the output from a Symphony NitrisDX BOB. The footage had come from a Sony EX3 cameras recorded at 35mBits 1080/25P onto Memory Stick and imported straight into a progressive timeline. The Avid plays back Psf which the Tek shows as 1080i (for the reasons discussed above). Laying this off to HDCamSR (a 5500 deck) gives a 25Psf recording on tape. The second screen shot is the Quicktime sample movie imported into a new 25P timeline - it just serves to comfirm that the BOB output is always Psf.



This last picture is the down-convert output of a Leitch X75 which is a great little get you out of trouble box (basically does everything->everything with a few extra tricks thrown in - profanity delay etc.) but it's not a multi-frame broadcast standards converter (like a Snell & Wilcox Ukon).

Although you can't see it from this screen-grab the SD output has had it's field-dominance changed and the quality of the video ain't great. This wouldn't be an issue for VHS/DVD review copy or if it was the pre-processed feed for web-conversion but it's not suitable for SD delivery.
For that the best option (short of a £20k Ukon!) is to use the SD-downconvert from the HDCamSR machine.

The futility of re-using old storage

I was over at a facility doing a site survey for a fibre network and the owner/operator told me how he planned to re-deploy his ancient 300gig LanShare storage system as an MP3 storage pool. I did a little mental calculation about the economics of re-using old storage; That model of LanShare consumes a bit less than a kilowatt of power - now I'm assuming he's paying seven or eight pence for a Kw/h and so by doing the maths (and bearing in mind the cost of a 300 gig drive - £69.00 inc. VAT today) he's burning that much electricity every three weeks! Even setting aside the cost of administrating ANY Avid storage (and the licensing considerations, needing client connection software etc. etc.) there is no good reason to re-use an old LanShare or Unity.
I had the same argument a few years ago with someone who wanted to re-use a 10x9gig fibre array - the cost of a fibre HBA to allow him to re-use it in a PC was many times the cost of a 120gig drive (and I didn't even do the power calculation) - it's NEVER worth it.

A facility I worked at in the mid-nineties had Paltex edit controllers (of a mid-eighties vintage!). Anyhow - back then the EPROMs containing the software were only 32 Kbytes big. Eventually the system software got to requiring 64 Kbytes of space and so they had to produce an updated system board that actually had the A16 line wired. Imagine my horror when (to avoid the £800 upgrade cost) I had to manually wire (with kynar wire) the most-significant address line on old 32K-capable system boards! By the time I'd finished a couple of them they looked like birds' nests and were about as stable as Charles Manson!
Incidentally - the kilobyte is an obsolete measurement of memory size. Back in the eighties skilled programmers could pack a lot of functionality into a 'K' - I saw a chess program that played a very respectable opening coded in that much space. Nowadays (when programmers are called developers and bolt objects together rather than writing computer code) the megabyte will soon the an obsolete term.
The megahertz is an obsolete term that refers to the speed of old microprocessors' clocks....

How Avid differs from all other broadcast manufacturers

Avid have this get out of gaol card they play often - it's called the ¨..that's not a supported configuration¨ reason. They play it whenever their badly implemented version of an industry-wide standard doesn't play nicely with other equipment. The first time I came across it was the way they do P2 protocol over RS422 on the ABVB-based Mac systems. I was working at Oasis TV back in 1996 when we started to hook original D5 machines (the Panasonic AJ-D580) up to 9500-based V.7 Avids. We noticed that when capturing the deck would often take off in the wrong direction and then reverse and pre-roll correctly. Often laybacks would fail or be a frame late. Eventually I borrowed a serial sniffer and stuck it across the RS422 out of the Avid and discovered the following.

• The Avid rarely issued commands in the 17-line window after the start of frame that P2 demands. Consequently the deck would queue the command and ignore it for a frame.


• The Avid would sometimes issue the pre-roll command before it loaded the counter - the poor old VTR would take off on the pre-roll only to realise that it was going in the wrong direction.

So, a broadcast grade VTR that conforms to every relevent standard doesn't play nicely with Avid's sloppy implmentation of an existing standard and their justification is that "...it's an unsupported configuration"!
I've just put in a couple of machines that rely on an outboard FireWire switcher. I would have sworn it was the switcher that was at fault but I had a Root6 ContentAgent to test the various ports with the VTRs. The Avid Mojos will drop the feed if you do anything with the switcher (like make another route!) and you have to re-launch Media Composer. It makes using FireWire decks a real pain and I didn't realise Mojos were so problematic until Graham sent me the following;

This just mirrors my experiences...
Firewire switches, hubs and splitters don’t work CONSISTENTLY. They just don’t. Firewire patchbays and good quality extenders DO.
I have tested half a dozen of these things and they just don’t work without a reboot, a reset, and a mess around.

The same can be said of SCSI, Fibre Channel, and even the way they handle the PCI bus - see a previous post here for details of their half-arsed ADAT implmentation.
Now, if a Sony VTR refused to record a standard PAL signal or a Grass Valley mixer wouldn't derive a key from an SDi feed then they would sort it out - I never heard the phrase ¨...I'm sorry, that's not a supported configuration¨ until Avid came on the scene!

Adrienne Electronics

Do you remember a BBC2 late-night show called Diners - back in 2002 anything that had the reality label attached to it got commissioned (although admittedly on very late in the evening). If you Google for it now there is scant evidence of it! I did find a John Walsh article from The Independent. Anyhow - one of the problems I had to solve for that show was using cheap Avids (software-only versions - ExpressDV back then) to capture or log live feeds with timecode. Of course the studio or OB sends you audio timecode (the kind that sounds like a fax and comes down a twisted pair cable) but all hardware-less edit stations assumed the timecode comes down the RS422 line as part of the machine control.
Adrienne Electronics do a range of really useful boxes to address these kind of problems - the AEC-Box-2 takes in audio code and has a 9-pin connector. It emulates a VTR but (being a solid box) doesn't actually play or rewind tape - it just tells the Avid it is doing so (in this case it's an Avid MCSoft with SDi Mojo). The really cool thing is that when the Avid asks for timecode down the RS422 the box returns what it is receiving on it's input. It's the ideal solution for using cheap workstations to log or capture proper studio or OB type material.
Now I'd been puzzling about this for ages last night (got home late from the studio where I was working) and it was only over my tea that I remembered solving the problem five years before - kinda like how everyone has forgotten Diners!

Got my Mojo working

I did investigate this the Production Show before last (2005) - I thought I'd so this but include balancing for the audio to make it a bit more pro - XLRs & BNCs on the back. I got Bryant to do me a quote for the metalwork and adding in the cost of a buffer card to balance/level match the audio brought it to about £250 cost to us. With that in mind I asked maybe a dozen people at the show who were looking at ExpressPro/Mojo if they'd consider it and what price - they ALL thought £250 would be a waste of cash.

Now - what with SDi Mojo maybe it's worth re-investigating. MC Soft (the current less-than-£5k Avid package) appeals not only to wedding videographers but broadcasters and serious facilities people. In fact, Root6 have asked my to prototype one up - watch this space.

Magic Avid!

This is a killer! Avid have a dual-boot solution that allows you to have both NitrisDS and SymphonyDS apps on the same machine - but rather than doing something modern with a partitioned drive and bootloader they have the Avid dual-boot option that uses a key-switch to power one of two system drives! All built into a nice metal panel that fits in a 5 1/4 inch drive bay and just switches the drive power. I laughed heartily when Joel showed me that.....

My four biggest beefs with Avid

• Digi002, ExpressPro Studio, and eight channel audio.
  
  To get eight channels in and out of a Digi002 console you need to use ADAT 'light-pipe' which necessitates a converter of some sort. Quite why a "pro" product relies on a domestic-style interface for multi-channel work is another topic (not too many VTRs, multi-track tapes or disks come with ADAT, but still). The thing that has really bitten us in the backside is that neither of the models Avid recommend work reliably with the Digi002 (the Fostex UC-8 and the Dua2) and the one gadget that does work (the Alesis A14) only works on short ADAT cables (this is a single-mode fibre - in any industrial grade application you'd expect it to work over kilometres, not be limited to three metres!). This flies in the face of Avid's advice - "you can run long ADAT fibres, but don't try and extend the FireWire between the workstation and the Digi002" - well, precisely the reverse is true! Big shout to my colleague Chris Bailey for figuring this all out and to Joel and Rhys who I worked late with last night out in the sticks in Hertforshire testing this (amongst other things).
  
• Mojo analogue video performance - still bad, noisy when in component mode (yet Avid claim it's broadcast quality - where, precisely?!). See a previous post here.
  
• Adrenaline and NTSC reference - when using Adrenaline in 525 mode it has to have a proper Sc-H consistent sync source - this is fine, but by letting people get away with a cheap'n'cheerful black & burst generator in PAL mode you give clients the expectation that they've gotten away with additional expense - if you're going to lower the bar then do it consistently or not at all.
• This pinched from the Avid-L today

  Almost as shocking as the actually time code problem is that Avid refuses to comment on it or address it. Pretty shameful.
  How about if I say that we're aware of it and committed to fix it? Would that be enough? Sincerely, Jeremy Kezer (Jeremy is Avid's principle engineer)

Still, compared to Final Cut Pro and Decklink these are mere annoyances!

This from the FAQ in Avid's sales guide (issued at NAB this year):

I've played with Media Composer Adrenaline on both Mac and Windows and there is a real performance difference. Are you making the Mac version run slower?
Of course not, we optimise for both platforms. At this time we are seeing significantly higher real-time performance on current Windows-based workstations than G5 workstations from Apple.

So now we know!