Currently a 60min DV tape = 13GB - What does a 60min HDV tape take up?

k993802 · #1 (**permalink**) 02-19-2007, 03:42 PM

Hi all,

I only discovered this forum last week so i'm a newbie, but its such a great source of info!

Apologies if this post is in the wrong topic area, I couldn't really decide where to put it!

I've been running Adobe Premier Pro for the last couple of years in order to turn what would be bland and boring holiday videos into something a little more cool.

In my experience it could be true to say that recording a full 60min miniDV tape using my Sony DCR-HC42E resulted in a raw .avi format file sized approx 13GB.

With the introduction of these new HDV camcorders I was wondering what sort of raw file size a HDV 60 min tape creates.

I am aiming to build another video editing PC in the coming month or so and am wondering what its going to have to work with raw material wise. I know the spec that I want to build, but i'm interested in what I'd need should I upgrade to a HDV camcorder.

Thanks in advance for any answers!

Mark W · #2 (**permalink**) 02-19-2007, 06:14 PM

I surmise this from the specs but I reckon a hdv file will be smaller. DV data rate is 25mbit/s, HDV data rate is 19mbit/s.

I wonder why? Seems odd they used less b width.

Andy Lockwood · #3 (**permalink**) 02-19-2007, 06:18 PM

http://www.microsoft.com/windows/win...HDFormats.aspx

Try this. Lots of info relating to your question.

Evereddie · #4 (**permalink**) 02-19-2007, 06:45 PM

Nice article Microsoft. Perfectly clear.... like a foggy window!

bert6280 · #5 (**permalink**) 02-19-2007, 09:49 PM

I thought that it was supposed to be the same. Someone will quickly step in and tell me I'm wrong, but one of the big selling points of HDV is that HDV cameras can use the same miniDV tapes because they use the same bandwidth as SD cameras - 25Mbps They do so because they record in a far more efficient MPG format. (SD uses DV AVI file format) So the resolution can go up, but not the bandwidth. The size issues are relevant at the editing stage, because some editors create and use an intermediate format created from the original HDV footage. The intermediate format files are in the region of 4 times the size of standard DV AVI files. Some of the latest editors now edit HDV natively, but you really need a fast PC to use them fluidly.

k993802 · #6 (**permalink**) 02-20-2007, 01:15 PM

Hmmm,

ok, so what I think you're all saying is that as it is compressed differently, the raw file isn't necessarily bigger, despite the higher quality of image.

However, due to stronger compression, the 'intermediate' files created by editing programs may well be significantly larger (meaning larger HDD will be required).

In addition, using a video file that has been heavily compressed is likely to require a higher spec'd PC (memory and CPU) as well.

So I think that what you guys are saying is that, compared to editing DV video, I am definately going to need a faster PC with larger storage in order to edit HDV?

Z Cheema · #7 (**permalink**) 02-20-2007, 04:11 PM

I think it also has more gaps between the main frames (Pictures) so if there is any dropout is normally quite bad, worse then DV

Mark W · #8 (**permalink**) 02-20-2007, 07:59 PM

DV is a 25ish mbit data rate with compression only being done within each frame - like jpeg.

HDV is a 19mbit data rate but the compression method is more like dvix or wmv, it compresses across many frames so is much more efficient, but as said this means it is much hrader to edit.

I havent heard about intermediate files but I only use vegas and i am pretty sure it edits all fiels natively.

DV and HDV tapes are EXACTLY the same.

Marc Peters · #9 (**permalink**) 02-21-2007, 12:45 PM

Originally Posted by Z Cheema

I think it also has more gaps between the main frames (Pictures) so if there is any dropout is normally quite bad, worse then DV

Without going in to to much detail, DV usese intraframe compression and therefore one frame is never dependant on data from another; drop a frame and ypu only lose one frame. HDV uses MPEG compression, which is based on interframe compression using a Group of Picture (GOP) structure. In this way you (and putting this veru basically) have a bunch of frames reliant on one key frame. So if you lose one frame in a group, you lose 'em all.

torby · #10 (**permalink**) 02-22-2007, 01:49 PM

I would reckon as you say 1hr equates to about 13Gb and from what Ive seen HD footage equates to about 43gb about 3 times as much....

oooops just re read the question...thats probably not what you asked at all...I actually thought you meant what the contents of a 60 min tape equates to when its captured....sorry...