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Old July 31st, 2010, 09:46 PM   #46
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That's actually a good question and it depends to quite an extent on how effective the lossless compression algorithms are for video files.

The LTO generations have the following native data rates

Generation 3 ...80 MB/S 2006 Capacity 400 GB Native

Generation 4 ..120 MB/S 2008 Capacity 800 GB Native

Generation 5 ..140 MB/S 2010 Capacity 1.5 TB Native

Generation 6 .. 210 MB/S Planned for 2012

Generation 7 .. 315MB/S Planned for 2014

Generation 8 .. 472 MB/S Planned for 2016 Capacity 12.8 TB Native

We've been pretty close to making the planned dates up to now and having a new generation every two years, but the technical challenges don't get any easier as we go forward so the future generations could be a little delayed.

If I look at Gen 5 you could potentially transfer a TB in around 3 hours at native capacity and data rate, but on average you could reasonably expect about twice as high a data rate so possibly an hour and a half to two hours might be a reasonable assumption.

The so called "Native" data rate is how fast the drive actually transfers data to the tape, so if the data compresses well you could really accept about 2X or 2.5X that data rate from the attaching systems

This all assumes of course that everything else in the system is optimized, which rarely happens perfectly in real life. It also assumes that you don't get many tape errors while writing. The way LTO deals with write errors is to just skip forward and start the transfer over, leaving a partially transferred file on the tape. But if the write aborts before completion, then the end of block/file indicator wouldn't be written to tape so the following read would also terminate and try again with the following data. Since they assume that the reason for a falure was a defect on the tape, they skip a ways down the tape and this can reduce both ultimate capacity and data rate. Fortunately, you don't usually see many stop writes.

I'll check on Monday with one of the technical guys and see if they have any good benchmark data for video. One of my clients used to sell LTO to the Japanese broadcasting stations for their archive of actual broadcast material so the gang in Tokyo might have some info.
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Old August 11th, 2010, 04:29 AM   #47
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I watched The Stone Tape last night, an old BBC ghost story made in 1972. It was all shot on video and the footage and audio quality were a bit poor in places, but it didn't matter because the story, direction and performances were brilliant. What I'm trying to say is that if a film were shot in HDV, and it were captivating and novel enough, would it need to be in a 4:2:2 50 Mbs format or could it have been shot in HDV and still get on television?
Ah, the old "content versus quality" argument! :-) My attitude is the same as it's always been. It's very, very rare that it has to be one or the other and TV budgets SHOULD be such as to allow the use of approved equipment. If we're looking at a minimum of an EX1 and a nanoFlash, it's not really that much more than a Z1, say, is it? Not relative to other production costs in the professional world.

I'm old enough to remember the Stone Tape when first broadcast, and I came across it on a DVD a number of years ago. Yes, it had stayed in my mind, and yes, I found a repeat viewing worthwhile. But I think it is firmly fixed in the 70's and in that respect the technical quality is part of it. I think if I turned on the TV to watch a contempory programme, and the technical quality was "Stone Tape standard" I'd be wondering what was going on.

Yes, content is more important than absolute technical quality, but there is absolutely no reson why both can't be had at the same time. That's why i think the argument is largely irrelevant, at least in a broadcasters mind. Yes, there may be times when it's essential to shoot on very small cameras for very good reasons, but I don't think that is what is being considered here.

Out of interest, how did you come to be watching the "Stone Tape"? I believed it was no longer available, and apart from those above a certain age largely forgotten about! :-) (Incidentally, if you haven't already seen it, The Stone Tape - Wikipedia, the free encyclopedia is worth a read.)
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Old August 11th, 2010, 02:17 PM   #48
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Quote:
Originally Posted by Stuart Graham View Post
I watched The Stone Tape last night, an old BBC ghost story made in 1972. It was all shot on video and the footage and audio quality were a bit poor in places, but it didn't matter because the story, direction and performances were brilliant. What I'm trying to say is that if a film were shot in HDV, and it were captivating and novel enough, would it need to be in a 4:2:2 50 Mbs format or could it have been shot in HDV and still get on television?
The point is OPINIONS are irrelevant - the final decision is made by the broadcaster. Do WHATEVER you want for cinema exposition (film fests) or DVD or online distribution but when we are talking BROADCAST, a different set of rules apply.

A "film" shot on HDV that sweeps through film fests and wins countless awards and is highly sought after by the television viewing public will likely be sought after by broadcasters BUT to intentionally shoot on non-accepted formats with the INTENT of seeking broadcast is foolish.
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Old August 11th, 2010, 04:22 PM   #49
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Jim: Thanks for all the info on tape backup systems, I will probably set up a tape backup system when I go tapeless.

David: I see what you mean, point taken. Quality + content for broadcast, not content before quality. I guess shooting on non-broadcast cameras is to be done only where it can't be done any other way. Like if the camera is liable to be destroyed (stunt shots), in car shots where big cameras might not be permitted for health and safety, or for undercover documentary filming and suchlike.

It's great that you've heard of The Stone Tape too :) One of the actors from my last film leant me a copy of it on VHS. It was released by the BFI at some point on both VHS and DVD, but it's no longer available :( I'm tempted to make a copy by connecting my XH A1 to the VCR with a SCART to composite connection. As it's no longer available it doesn't seem piratical to do that. You can pick it up second hand on ebay but it's pretty extortionate.

Shaun: Thanks for that, a good point well made! I'll keep it in mind for the future!
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Old August 12th, 2010, 12:14 AM   #50
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Stuart, have you considered buying used? A used EX1 can be had for about $4,000 USD, with media cards. It'd be a great upgrade from an XH-A1.

Considering the EX1/3 or the XF300/305: they seem to be great cameras for the price. You get a lot for the money. There's another member on this forum who owns the EX1, EX3 and the XF305, and he says you can't go wrong with either one. I'm considering getting a second camera and all three of these are at the top of the list. I've shot with the EX3 and it's an excellent camera. I would like to try the Canon one day. Right out of the box, the XF line was approved for HD acquisition by your own BBC, which is not an easy thing to do. The EX line, using the 35mbps, was not on "the list" (although they might have been used in BBC productions, maybe with the Nanoflash?). Perhaps in this case, codec, regardless of imager size, was indeed important.

Whatever you decide, move away from HDV. Seriously. Because even though your primary use of the camera is to make films, you can also use it as a general video production camera. Might as well make some cash in-between films.
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Old August 13th, 2010, 04:47 AM   #51
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Hi Glen

That's a good idea. I'll have to hunt round on ebay a bit and see what's out there. Or maybe someone's flogging one on DVi.

Those are all great cameras! Eyes widen and tongue lolls out of mouth...

Good idea to make cash in between films as well, time is the problem though as I have a full time day job (a non-video related one).

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Old August 24th, 2010, 06:39 AM   #52
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Can I use the Same Lenses on both my SLR and Video Camera

I own a Canon 550D SLR and one thing I've considered is upgrading to a full frame SLR and using its 35mm lenses on both the SLR and my next video camera - thus saving on buying two sets of lenses.

Has anyone else gone down this route?

Would the 35mm lenses have to be from the same manufacturer as the video camera in order for them to work properly?

In other words if I buy Canon EF lenses will they work on a Sony EX3 for instance?

Would you also have to have a 35mm adaptor to attach to the video camera? Or are there video cameras with big enough sensors to take a 35mm lens?
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Old August 24th, 2010, 07:18 AM   #53
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Quote:
Originally Posted by Stuart Graham View Post
I own a Canon 550D SLR and one thing I've considered is upgrading to a full frame SLR and using its 35mm lenses on both the SLR and my next video camera - thus saving on buying two sets of lenses.

Has anyone else gone down this route?

Would the 35mm lenses have to be from the same manufacturer as the video camera in order for them to work properly?

In other words if I buy Canon EF lenses will they work on a Sony EX3 for instance?

Would you also have to have a 35mm adaptor to attach to the video camera? Or are there video cameras with big enough sensors to take a 35mm lens?
Whoo, Stuart, there's a lot you need to know about 35mm lenses and video cameras.

To put 35mm lenses on a video camera, yes, you will need a 35mm lens adapter, like a Letus or Red Rock. And in that case, there are different lens mounts for different makes of lenses. Use whichever brand of lens you like.

But the problem is, they can be a bit unwieldly and they rob the camera of light sensitivity. If you need the benefits of DSLR lenses, it now makes sense to just buy a HD-capable DSLR and skip the hassles of the 35mm adapter rigs. The Canon T2i, for instance, costs less than an adapter rig and has a large imaging sensor to boot, certainly far larger than the EX3s. Why not just use it when you need the benefits of a DSLR? It can be had for under $1,000, with lens.

As of right now, there are only two video cameras that can accept DSLR lenses right out of the box - and they're not even released yet, although both will be available by year's end: The Sony NEX-VG10 ($1,999) and the Panasonic AF-100 (maybe $6,000?). The Sony will need adapters to accept Canon lenses, not sure what lens mount the Panasonic has, although I doubt it's a Canon. Still, I'm sure it will accept Canon lenses with an adapter.

If you have a DSLR I really don't see the need to get a lens adapter for your video camera. Use whichever camera suits your needs best, the right tool for the job. Because as nice as the images are from DSLRs, in my opinion, they will never truly replace the video camera. But both can work side by side.
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Old August 25th, 2010, 06:42 AM   #54
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Thanks for the help Glen.

Quote:
Whoo, Stuart, there's a lot you need to know about 35mm lenses and video cameras.
Definitely, I'm quite baffled by all that stuff!

Will things like autofocus and IS work when you use the lens adaptors?

I agree, I don't think dSLRs can replace video cameras. I think I'd find it difficult and frustrating doing video on a dSLR all the time. For one thing I'd miss the zebras and it'd be a job doing smooth zooms. And not being able to angle the viewfinder to make looking into it easier would be very awkward. Worst of all, with a dSLR, you have no XLR inputs for audio and you haven't got manual audio level controls. And no dSLR is going to be broadcast approved.

I'll keep my eyes peeled for those new cameras, it's good to have more options to consider. It's the long term cost saving I'm thinking of mainly - lenses are darned expensive and having two sets of lenses is too dear for me really.
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Old August 25th, 2010, 07:41 AM   #55
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Originally Posted by Stuart Graham View Post

I watched The Stone Tape last night, an old BBC ghost story made in 1972. It was all shot on video and the footage and audio quality were a bit poor in places, but it didn't matter because the story, direction and performances were brilliant. What I'm trying to say is that if a film were shot in HDV, and it were captivating and novel enough, would it need to be in a 4:2:2 50 Mbs format or could it have been shot in HDV and still get on television?
That would've been recorded on 2 inch quad, which was the broadcast format of that period. Most UK made broadcast TV is commissioned rather than an acquisition, so you'd need a stand out production that's of interest or good contacts (or both) to make a sale.

HDV is used on standard def productions, so no problem there.
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Old August 25th, 2010, 04:05 PM   #56
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Thanks for the info Bryan.

Had a look at 2" Quadruplex on Wikipedia, it looks like heavy duty stuff!

Didn't realise HDV is used for standard def productions, as long as it's not a HD channel would the broadcaster accept HDV material?
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Old August 26th, 2010, 04:23 AM   #57
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They even accept Mini DV for standard def programmes, so HDV is fine. It's regarded as SD by the the UK broadcasters, but certain percentage of a HD programme's content can be shot on HDV.

BTW They used to edit 2" Quad by physically cutting the tape, rather like you can do with 1/4" audio tape. They had a fluid that revealed the magnetic patterns made by the sync pulses on the tape, so the editor knew where to make the splice.

Once they had multi machine edit suites they no longer had to do this.
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Old August 26th, 2010, 04:54 AM   #58
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Thanks for that Brian, I didn't realise HDV was acceptable for SD programmes.

I'd never have guessed they cut the tape physically, I thought that was just a film procedure, interesting stuff.

Sounds a bit scary to do it, do you know if they'd back up first?
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Old August 26th, 2010, 05:42 AM   #59
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As far as quadruplex goes, then in the earliest days cut editing was indeed the only way to do it. As far as backup went, then two copies would always be made of any important recording - mess up an edit and the other copy could be used. But don't underestimate how much extra work that may cause.

Electronic editing came in after not too long in a basic fashion - and well before the multi-machine timecode suites. Technically, it needed a series of delays to accurately time the switching of various parts from playback to record, a burst of tone on the cue track set everything happening.

Practically, the in point was found on both the recorder and the player, both machines were manually rewound ten seconds (looking at a clockwork counter), then both started together. Initially both were in playback, they both locked up together, then the record machine would flip from playback to record. It would be normal to rehearse the edit, then adjust if necessary. The cueing point was "marked" quite literally with a chinagraph pencil on the back of the tape, and adjusting the edit was a matter of manually moving the tape a few inches to make a new mark!

Electronic and cut editing co-existed for quite a long time, the former gradually taking over. Cut editing was still used (albeit rarely) in the late 70's - it's advantage being speed for certain types of work (such as sport). An example would be shortening a football match for transmission very soon after play. You may want the first and last 15 minutes, but lose the middle. Electronic editing would have meant at least 30 minutes of pure dubbing, let alone the time to set up the edit, cut editing was far faster for something like this.

As far as "The Stone Tape" goes, then the quality issues you noticed and mention are far more due to the cameras used than recording format - "comet tailing" and registration errors were two of the most noticeable problems on programmes of that era.
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Old October 17th, 2010, 03:22 PM   #60
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Fix for Tearing Artefacts Seen When Playing Back Avid Footage

Just in case anyone has the problem with horizontal tearing artefacts when reviewing footage in the Avid like I did - I've worked out what the problem was. You need to turn V-sync on in your graphics driver. To do that open up your NVIDIA control panel then navigate to:

3D Settings
Manage 3D Settings
Global Settings

Then set "Vertical Sync" to "FORCE ON"

That should be it fixed!

Hope that's of use to someone out there, took me ages to figure it out!
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