non-realtime capture of DV?

[trpltongue]

Hello all,

I've spent the last few weeks capturing all of my DV's to PC via firewire and Ulead video studio. Unfortunately, all of this has been in realtime. Are there any apps that can capture un-compressed DV via firewire in non-realtime (faster)?

Isn't DV a digital bitstream? If so, shouldn't we be able to pull the bitstream off of the DV tape faster (like reading from a hard drive)?

Thanks for any info.

Russ

[Reflux]

I know Sony has a 2X DV/CAM-player but they are REALLY expensive and I'm not sure if any software supports this? You'll probably have to live with it for now or instead buy a harddisk-based recording solution for your camera.

[trpltongue]

Yeah, I saw the MCE hard disk and thought it was sweet! But $600 for 90 minutes

It seems strange that we can't get this DIGITAL data off of the tape any faster. It's not like we're converting it to analogue and then back to digital. It's a straight digital to digital copy.

I guess I'll go back to daydreaming.

Russ

[sdsumike619]

Is it possible to have my camera plugged in via firewire and capture uncompressed DV AVI to my hard drive AS I'm shooting? Seems like that should be possible?

mike

[MpegEncoder]

Is it possible to have my camera plugged in via firewire and capture uncompressed DV AVI to my hard drive AS I'm shooting? Seems like that should be possible?

mike

You can "transfer" directly from the camcorder without using a tape.

BTW, I've said it before and I'll say it again DV-AVI is NOT UNCOMPRESSED

[sdsumike619]

how?

[MpegEncoder]

how?

Just turn on the camcorder and start "capturing" the DV output.

My Sony TRV320 works fine that way.

[choirislife923]

DV a digital bitstream? If so, shouldn't we be able to pull the bitstream off of the DV tape faster (like reading from a hard drive)?

if you want to use a regular old 7200 RPM HDD with faster transfer, good luck. since DV is at 25mbps, capturing at 2x would be 50mbps, which would problably overload a good ol' EIDE HDD. i do not know about SCSI (pronounce it "sk-uz-zie" [skuzzy]) drives though. those crazy things run at around 12500 RPM, but EXPENSIVE!

[PIntag]

Hello all,

I've spent the last few weeks capturing all of my DV's to PC via firewire and Ulead video studio. Unfortunately, all of this has been in realtime. Are there any apps that can capture un-compressed DV via firewire in non-realtime (faster)?

Isn't DV a digital bitstream? If so, shouldn't we be able to pull the bitstream off of the DV tape faster (like reading from a hard drive)?

Thanks for any info.

Russ

Theoretically, yes, it should be very possible. However, in order to capture faster than realtime playback, the camera motor would have to read the tape faster. This shouldn't be too much of a problem, since most cameras also support fast forwarding. Has anyone tried a DV capture with the camera on FF instead of just play? Somehow, I doubt it would work, but I haven't tried it yet.

Also, there are DV reading devices on the market that install into your PC internally (external ones too?). If anyone here has one of these, do you know if you can capture faster than realtime with it?

[xenon2000]

if you want to use a regular old 7200 RPM HDD with faster transfer, good luck. since DV is at 25mbps, capturing at 2x would be 50mbps, which would problably overload a good ol' EIDE HDD.

DV is 25mbps as you said, but that is MegaBIT, not BTYE, so it works out to about 3.5 MegaBtyes per second. And if your current IDE HDD has a hard time keeping up with 3.5 MegaBytes per second, then I recommend you get a new HDD.

The problem with transferring DV faster than realtime (1x) is not the firewire connection or standard IDE HDDs, but with the camcorder tape drive system. Not only would the tape need to physically move faster, there are tape friction issues to think of and of course more expensive camcorder electronics to process and error correct the faster data reading from moving the tape faster.

Not that it can't be done, it can. Even if you increased the transfer 4x, any standard IDE HDD would be able to handle 14-16 MegaBYTES per second.

http://encyclopedia.laborlawtalk.com/Dv

This link also explains the DV transfer speed in PC terms. As well as other components of DV media.

[Cornucopia]

When FF a tape, you normally only see it skip every couple of frames. The physical tape drive mechanism can't keep up AND stay in sync on every frame. Might be possible if there was a separate "2x-only" player unit that had adjusted head wrap angle and higher BW electronics, etc., but now you're talking $$$$!
That's one of the major real benefits to recording directly to HD (as in the case of the Focusrite products) or the P2-type memory cards (as in the case of Panasonics newer products). That and random access for editing.

Scott

[xenon2000]

Yep, you definately can't just FF and capture and expect to get anything useable. Certainly won't get all the frames. Garble at best.

Definately big bucks for 2x transfer tape drives. And as already mentioned, this is where leaving tapes and moving to hard drive or memory setups would be a huge benefit to editors. I personally would like a HDD solution since a huge amount of time would be possible. Though power use would be higher than a memory solution. Yet I would imagine an HDD setup would yield about the same power driain as a tape drive setup.

Panasonic has a good concept going, but not sure if it's a cost effective solution for the much lower cost normal consumer level hardware. At least not right now. 2.5" removeable HDD seems like a prime solution. But I haven't seen any development in this regard.

Of course, if power and the size of a camera rig was not an issue. One could always setup a laptop and DV camcorder as a rig for direct recording to HDD on the laptop. Then it's already on a drive for editing. Also gives a nice large display to monitor the camera while filming, yet the delay on the laptop display makes that benefit fairly useless for on-the-fly adjustments.

[edDV]

...

Isn't DV a digital bitstream? If so, shouldn't we be able to pull the bitstream off of the DV tape faster (like reading from a hard drive)?

Thanks for any info.

Russ

Yes reading DV over IEEE-1394 is a bitstream. The bitstream source is the hardware DV codec chip in the camcorder. The DV codec chip can have three sources

- Camera Section - yes it can record to tape and feed a DV stream at the same time or one of either

- Analog Pass Through (if supported)

- Tape playback - yes at 1x. If you want >1x you can buy a DVCPro camcorder or deck for >$6,000 for the camcorder and >$1000 per 20min P2 card
https://eww.pavc.panasonic.co.jp/pro-av/sales_o/p2/p2card/
or >$10k for a hardware mechanical 2x transfer
https://eww.pavc.panasonic.co.jp/pro-av/index.html

A stream from the DV codec is just that, a data stream. A data stream should not be confused with a file transfer under an OS. The DV data stream is constant, it is transitive. By that I mean that like a fly ball you better catch it because the tape or live action isn't going to back up by itself if you miss the bits coming at you.

The 1x speed of the stream is limited by the mechanical tape transport and the DV Codec chip. It has NOTHING to do with IEEE-1394 which can go up to 10x faster if bound as a network device. A DV stream transfer has nothing in common with a file transfer. There is no file to transfer. It's a stream, get it?

[edDV]

Price break !

After NAB, Panasonic announced a price drop for P2 cards. Now you can buy a 8GB P2 card for $1700. This is good enough for 8 min of HDTV or 40 min of DV per card.

These cards will transfer at up to 640Mb/s (100 sec) if plugged into a computer PC card slot.

http://www.camcorderinfo.com/content/Panasonics-P2-Format-Explained.htm

Expect this technology to trickle down to consumer camcorders over the next few years.

[xenon2000]

Yep, it's a data stream. I don't think anyone here said otherwise. And in order to get a faster data stream via ANY connection then the root of the problem needs to go faster. And with Tape based DV camcorders, that means the tape stream needs to be read faster. I don't think anyone was implying that it had anything to do with the connection type.

I myself, just wanted to clarify that IDE is plenty fast enough for DV transfers, even if the data stream was increased 4x or even more.

I myself don't care that it's 1x straight off my camcorder. Then again, I don't transfer tapes all day long either.

[trpltongue]

Wow,

I just happened to stop by today and I saw this thread brought back to life

Thanks for all the comments and insight. I did relegate myself to the monotonous task of capturing 1 tape at a time. Painfully slow but effective never the less.

Those hard drive systems are coming down in price now and if they weren't so bulky they'd be a pretty good alternative to using DV tapes. Oh well, for the forseable future I'll just transfer at 1X.

Thanks guys/gals,

Russell

[hsugawar]

Yes, it's a bit stream, but it's different from what you may think. The IEEE1394 defines two different transfer modes, asynchronous and isochronous. The former is similar to any inter-computer communications; request-response based so that any transfer rate is possible (as long as the medium allows). The latter is a fixed-rate constant streaming mode just like digital TV feed or digital audio connection; no handshaking, no nothing. I believe most, if not all, camcorders support only the latter at a x1 speed.

So, unless you can afford a very expensive special deck mentioned above, forget about a search for any such software or whatsoever.

hiro

[edDV]

Yes, it's a bit stream, but it's different from what you may think. ...

The latter is a fixed-rate constant streaming mode just like digital TV feed or digital audio connection; no handshaking, no nothing. I believe most, if not all, camcorders support only the latter at a x1 speed.

hiro

Tha pretty much describes a DV stream. Datarate is controlled and limited by the codec chips in the camcorder.

[monstermash]

I have a sony dsr 11. This deck will run at 2x even when loading a dv tape to my pc. Using Adobe premier 6.5 it will capture 50 frames per second(PAL), and 1 hours footage will still equate to 12.5 GB on the hard disc. The quality is as good as any other download but the resulting file will also play at 2x when dropped on the timeline. If you slow it down to normal speed (make the speed 50%) it then must be rendered to output to anything(DVD/DV/Analogue) this not only defeats the purpose of halving your download time it also uses twice as much disc space for preview files. A standard IDE disc(7200rpm) has no problem capturing 12.5 GB in 1/2 an hour as I had no dropped frames throughout the whole hour either to my operating system drive or a pair raided together specifically for video. If someone were to create software that would allow this then I could save at least 7-9 hours a week. Id be willing to pay a substantial sum to anyone who could do this

[edDV]

I have a sony dsr 11. This deck will run at 2x even when loading a dv tape to my pc. ....

I read this and wondered why nobody has ever mentioned 2x transfer with a DSR-11?

Then I scanned the manual and it wasn't in the features list.
http://art20.art.utexas.edu/%20FacultyProfiles/BH_links/downloads/DSR-11.pdf

Then I read closer as I should have in the first place. Are you using the +/-3x playback speed feature to transfer video to a PC?

That is far from a quality way to do a transfer. The 2x playback process tosses fields and even full frames for over 2x.


PS: Even the $4600 DSR45 only supports 1x transfer
http://bssc.sel.sony.com/BroadcastandBusiness/DisplayModel?m=10014&p=16&sp=113&id=64552