DVL-Digest 781 - Postings: Index Best LCD Monitors? (TFT Active Matrix?) RS-232C vs. RS-422A striping tapes Best LCD Monitors? (TFT Active Matrix?) - "Perry" I watched a DVD on a top price Sony Vaio a few weeks ago and it looked horrible. There was nothing in the shadow areas at all, and it looked very lifeless and flat compared to the same DVD on a CRT screen. I thought it may be the PC gamma thing, but I've just got a 15in Apple Studio LCD to go with my G4 and it still doesn't look right. It's better than the PC but I wouldn't use it for any sort of picture evaluation. It may be the MPEG2 decoder of course. I'll take some time to look at some trusted DV material but I'm not hopeful. What it is very good at is viewing angle tolerance which on many TFT screens (eg the Vaio) can be terrible. Matching even crt video and computer screens has always been difficult, they tend to use different phosphors and as we said there is a gamma difference. The new Sharp LCD televisions are getting some good press, but I saw one reviewed (in a mag) with a price tag of ,000!! Perry Mitchell Video Consultant http://www.perrybits.co.uk RS-232C vs. RS-422A - "Perry" There is always some confusion with this! It is a multi-level thing: 1) RS-232C & RS-422A are officially just different specs for serial interface ports. They spec the connectors and signal voltages etc. RS-422 is 'balanced' and capable of much longer cable runs and is generally a more rugged format. 2) Sony decided to use the RS-422 I/F on all its broadcast machines, whereas the industrial machines tended to have RS-232 to connect to computers of that time. They also created a complete RS-422 machine control protocol to allow use of editing and remote control. They made this protocol freely available to the industry and it has become the standard broadcast interface. 3) This protocol (unfortunately often called 'Sony RS-422') involves not just a set of command software codes, but a complete hardware regime. Many of the codes are 'Macro commands' which assume the provision of servo sub systems and a high level of 'intelligence'. So for instance, the 'Edit' command assumes there is an edit controller built in to the machine, and this in turn relies on a full capstan servo and synchroniser. 4) When these commands were only on expensive broadcast decks, there was no problem, since all machines were built with the requisite hardware. Many modern decks, particularly the cheaper DV machines, simply don't have this hardware and therefore CANNOT utilise proper Sony RS-422 control as commonly understood in broadcast circles. 5) RS-232 control was far more randomly organised, often with a control protocol peculiar to a particular machine. The protocol is often simply a 'remote control' of the deck control panel functions, although sometimes extra functions are added. There is no reason why a similar limited protocol cannot exist but using the RS-422 connector, but this does not make it the same as having the full broadcast style control. 6) In terms of broadcast engineering, NO Firewire controlled DV deck has a real editor. The DSR-20,20,11 etc enact a 'back space edit' as used in camcorders, which is just a carefully organised crash record with no real control. It usually works, mainly because the DV format is so simple (no control track) and tolerant of tracking errors. Perry Mitchell Video Consultant http://www.perrybits.co.uk striping tapes - "Perry" Hopefully Bertel & Alexis will spend some of their donated cash on an FAQ server, and this will definitely be in the top ten! It's not your fault Wes, you've probably only just joined us. Anyways the answer to your question is that no, striping DV tapes doesn't create a permanent timecode and cannot prevent timecode discontinuities. The best that can be said is that it ensures that the timecode will never be reset to zero in mid tape. Most folk think it is a waste of time and head hours. Perry Mitchell Video Consultant http://www.perrybits.co.uk (diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-) [up] |
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