FX1 muted still frames during Shoot?

L

LongSound

New member
Anyone heard of this rumour where the FX1 actually has 'error' frames, where by you'd see muted still frames during a video shoot? These frames last for half a second and they happen randomly. I am not sure of further details, but I hope that someone could clear up this rumor. Anyone could clear this up? I do not own the FX1 thus I wouldn't know its utmost performance, but i believe someone here could have sufficient experience to explain... thanks! :)
 
Re: FX1 muted still frames during Shoot?

It's not a rumour, it has been talked about pretty extensively.  It has to do with the mpeg compression, and how it generates only 1 actual frame for every 15 frames.  If that frame has an error, it will be reproduced for the consecutive 15 frames, thus causing the 1/2 second loss of information.
 
Re: FX1 muted still frames during Shoot?

Hmm... is that something to with tape error? Could you direct to me the discussion of this problem as I would like to find out more about it... Thanks :)
 
Re: FX1 muted still frames during Shoot?

[quote author=scharky link=board=sony;num=1103782628;start=0#1 date=12/22/04 at 23:03:42]If that frame has an error, it will be reproduced for the consecutive 15 frames, thus causing the 1/2 second loss of information.[/quote]
Actually, let me clarify -- if *any* of the frames in the group has an error, the camera drops the whole group.  At least that's how it appears to be, as I haven't seen an HDV dropout of any less than what appears to be 15 frames, so it appears that there must be some sort of overall error check being done on the whole group or something. Not sure about that, but I've seen maybe 10 dropouts and they all look like the screen freezes for the full duration of a half second.

It's not a rumor, it's a fact of life.  I've had it happen to me, and there are reports of it happening to others; on DMN they were talking about some Japanese boards that were complaining about it because they've had the camera longer I guess.

On DV, you might get a tiny dropout on one particular frame, that would result in a small glitch that shows up in maybe five or six areas of the screen for 1/30th of a second.  On HDV, that same type of tape error ("dropout") causes the whole 15-frame group to drop.  So the camera "freezes" on the last good frame it had, for half a second (the duration of 15 frames).  This wasn't so much an issue with the JVC, apparently, because the JVC's 720p mode used a smaller 6-frame group as opposed to the 15-frame group of the Sony, which makes the freeze-ups much more noticeable.

I have had it happen to me, I've seen it in others' footage, and I've seen it happen when recording footage back out from the computer to tape.  It's one of the primary reasons that I canceled my Z1 order and decided to let the whole HDV thing "settle down" before buying into it.  If you had something like a Firestore for HDV, I think you could minimize the risk of it happening to you... but currently there is no such device.  So all you can do is use the very, very best tape you can find and hope that you don't get hit with a dropout, especially in a crucial scene where you can't cut away (the Japanese discussions referenced above were saying they couldn't trust the camera for shooting weddings in particular).  Sony introduced a new $18 tape specifically for HDV recording, and I can't help but wonder if it's not related to the dropout issue; I'd strongly recommend using it.  Dropouts are not a frequent occurrence, maybe once or twice per tape (maybe much more, maybe much less, your mileage may vary) but when they hit they are devastating.  DV dropouts are very minor and can even be repaired; HDV dropouts cannot -- you lose a whole 15 frames.
 
Re: FX1 muted still frames during Shoot?

Barry, I'm glad you pointed out the problems with crucial footage. This is something I have been barking on about for some time, often getting shot down by hardcore HDV supporters.

A while ago when I suggested that I certainly wouldn't trust HDV for critical events such as weddings I was told that I was overreacting and that dropouts are so rare that they are unlikely to happen. The problem with this however is that if you are shooting a wedding and it is the one time you DO get a dropout you are screwed. Trying to explain to the couple that their wedding video has been ruined is not something I would want to do, especially given that many people who have taken up the idea of the FX1 for such events are charging a lot more than for DV!

What is more we have yet to see the long term effects after the FX1 has been in use for a while and the heads become more worn, or gunk builds up on them. Using a head cleaner regularly is one solution, but I'm sure this will just have the effect of wearing out the heads faster.

As you say, if HDV does take off and we are left with no option I guess we'll have to get an HDV camera. But if Panasonic do introduce an DVCPRO-HD camera things will become very interesting.
 
Re: FX1 muted still frames during Shoot?

Yeah, that's pretty much my position -- in my experience the dropouts were rare, but that's with a brand-new camera. On my DVX I never got even a "sparkly" dropout for months and months, although now with the camera nearing 2 years old, I get dropouts maybe five or six times a tape (which is still no big deal, as they're always contained to one frame and can easily be fixed in post). It's annoying, but not deadly, and it's one reason I just ordered a Firestore FS-4 from Rush.

But with HDV, it remains to be seen if it'll develop into a significant problem. I already would be hesitant to shoot something vital on it, because of the unknown factor. I'd feel *much* better with a duplicate recorder in place, either an HDV-aware FireStore or a small deck or something... anything...

and that's one reason (among many) that I'm just stoked about the prospect of DVCPRO-HD... each frame is individually compressed, not in any group, so even if there were to be a dropout, it'd be treated like a DV dropout and not lose an entire half-second of footage! Well, that plus it's 4:2:2 instead of 4:2:0, and it has 8 channels of uncompressed audio instead of two channels of compressed audio...

I think with the addition of an HDV-aware FireStore, the dropout issue would become more of a non-issue for me, so I'd just plan on factoring in the $800 cost as part of the cost of doing business with HDV. Hope they release one soon!
 
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