Monday, November 10, 2014

The death of videotape; long time coming.

Say it ain't so! I read the news today, oh boy.....
Sony is to stop selling its range of ½-inch tape machines and camcorders in just over a year’s time. The manufacturer has targeted March 2016 as the date by which it will cease sales and distribution of its professional VTRs and camcorders, owing to what it described as “the global trend of migration towards file-based operation”.

VTs have been a constant feature of my 26 years in broadcast engineering - I spent three years in VT maintenance when I was in BBC TV News and all through my time in facilities in the nineties/early noughties and my last dozen years working for a reseller the most dense way of storing data (which is what video has been for twenty years) is on magnetic tape using a rotating head-drum. 

VTRs are mechanical and hence unreliable; you can't pull rust-on-sellotape (a crude description of videotape) over a rotating metal drum without things wearing out and when I started I estimate that at least a half of all broadcast engineering hours were spent fixing decks. I certainly enjoyed that mix of electronics and mechanics and when I left BBC TV news my supervisor in VT maintenance had this made for me - at the time he reckoned I had done more than a hundred head-drums.

So, here are a few memories about VT formats I have had to deal with. It was all analogue when I started with the D1 format just starting to make inroads. By the mid-90s DigitalBetacam had become the predominant format for most production and post-production and Sony continued their domination of tape formats with HDCam and HDCamSR in the late nineties/early noughties. Since then it's been disk-based (XDCam) and flash-based (SxS, P2 etc etc.) - I haven't done anything more than cleaning a tape path or head-drum in the last decade but I used to be a pretty good VT-fixer!

  • 2" Quad; The original broadcast tape format which was on the wein when I joined the Beeb. At Lime Grove studios we did have a couple of Ampex VR 2000 machines. These beasts needed a compressed air feed to hold the tape on the transversely rotating drum. They weren't used for editing, just for archiving P as B recordings. I remember watching an episode of "Star Trek" (original!) being transmitted and marveling at home good composite pictures could look.
  • 1" C-format; specifically the Ampex VPR-2B (which was the BBC's 1" of choice) was a bit more of a workhorse machine. Again, BetaSP and Umatic HiBand where more prevalent at BBC News when I was there but when I went out into the independent industry in 1993 1" was a lot more widely used, particularly the Sony BVH-series machines (the choice when I was at CTV in St John's Wood) and then the Ampex VPR3 when I got to Soho in 1994 mastering to an analogue format was already diminishing.
  • BetacamSP; The BVW75P was the first piece of broadcast equipment I got to know to the component level. The summer after I joined the BBC they bought three hundred of them and I jumped on the overtime to do acceptance testing. Consequently I got to know the signal path and then in 1990 I got transferred to VTR maintenance and pretty much serviced the same machines I'd been taking delivery of two years before. They were the broadcast workhorse until the late nineties and I still see them. When I went to Nigeria the whole place was still running on them. Here are some photos of the insides.
  • D1; I didn't get into Soho until the second generation of D1s had arrived - the DVR2000 series (the 1000 series had half a rack of processing for trick-speed playback). D1 was the first 8-bit uncompressed SD VTR format. All the high-end facilities in Soho made good money out of them - when you could hire a 3 machine D1 room for £650 an hour! Many a time I heard engineers dismiss DigiBeta for it being compressed but I've NEVER seen Digi compression artifacts but I have seen shallow ramp banding on D1 (8-bit vs 10-bit). D1 decks were very expensive (£100k) and cost an arm and a leg to maintain. However - being able to do more than half a dozen generations on and off tape gave rise to all those effects heavy pop videos in the early nineties.
  • D2; Sony quickly realized that they'd need a composite digital machine for run of the mill TV production work (i.e. people who needed a drop-in replacement for 1") and so they bought the format off Ampex in some complex licensing deal that allowed Ampex to sell badged BVW75s. Ampex's VPR300 was a terrible machine; we had them at Oasis TV and you could often not get recordings made in the morning to playback on the same machine in the afternoon. After that the Sony DVR28 was an eye-opener. It could stripe tapes at high speed as well!
  • D3; Like D2 a digital composite machine but like D5 a 1/2" tape path which meant a practical all-in-one camcorder was possible. The BBC embraced the AJD350 the year I left and according to a pal at Panasonic of the first 98 machines they never got more than sixty working simultaneously. They format got really good after v.2 software when stability, RF performance etc improved. The operational side of the machine was entirely unlike Sony with a very complicated screen surrounded by buttons. Panasonic had to replace heads - almost no usable serviceable parts inside...!
  • D5; Channel Four were the only UK broadcaster to commit to D5 which was Panasonic's answer to D1 (but, a 1/2" format with 10-bit video, uncompressed - eventually there was an HD variant as well). You could tell the machine ran so close to the edge in terms of heat performance. We had two of them at Oasis and every morning I would pull out the long boards (below the tape transport) and re-seat all the chips - a day's worth of heat made all the socketed devices rise up. The machine shared mechanics with the AJD-350 D3 machine and with an option decoder board would replay D3 tapes. The tape-stock was the same in both cases and when I was at CTV we would send "D5" masters to Channel Four which were really D3 recordings with a D5 card in the tape sleeve! They never spotted it and it saved us hiring D5 machines (we owned D3). The rumor at the time was that C4 had been given the initial set of machines free to establish the format which was (even then) viewed as entirely unsuitable for a broadcaster. I never id much maintenance on them save cleaning etc. You had to send them back to Panasonic for heads etc.
  • DigiBeta; Whereas the first gen digital VTs (uncompressed, either 230mBits/sec for D1 & D5, 155mBits/sec for D2 & D3) required manual tracking for record like 1" the DVW-series 1/2" Digi had a pilot tracking tone system that allowed the machine to track itself for record. It could even do an insert edit if the control track was damaged by driving the phase of the scanner-lock based on the difference in signal strength between the pilot tones and the head and tail of each video track. Consequently I rarely saw machines that made incompatible recordings (that was a constant feature of all the earlier digital VTR formats).  The DVW was also the first machine to feature a Viterbi decoder in the bitstream path off tape and so you tended to get a green channel light (no error correction or concealment) until 1800hours of tape wear and then over a couple of days it would go to orange (error correction) to red channel condition (error concealment). Compared to all those earlier formats (I used to clean the heads on D1 & D2s every day of use!) they had a very low TCO.
  • BetacamSX;
  • DVCPro / DVCam / miniDV;
  • IMX;
  • HDCam;
  • HDCamSR;
  • Umatic;
  • VHS;

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