DV quality and encoding

[kenleeliew]

Hi there! I have recently gotten myself a sony handycam dcr-hc21e. What concerns me, is that the miniDV tapes are really burning a hole in my pocket. Therefore I would like to reuse those tapes over and over again until they finally and totally wear out. 8) Hence, I would like to enquire if the original tape would be exactly identical to the new one copied. (by means of transfering the dv from the first one to the computer, then on the second one). In this way I can have those dv tapes virtually in my computer's hard disk.

Another thing, the sony dealer always mentions that the videos are transferred to the computer in MPEG1 format. Now, isn't MPEG1 just a lossy format? I thought DV was supposed to be uncompressed.....(although the resulting DV file is indeed the usual 13GB per hour). Please enlighten.

Thank you.

[daamon]

Hi kenleeliew,

Because the video is in a digital format, when you're copying from tape to PC, or PC to tape - it is exactly that: a copy.

In fact, it's more accurate to think of it as a transfer - much like you transfer data from a floppy disk to your PC and back to another floppy disk. The file remains identical, as will your video footage and, so, its quality. This is all as long as it stays in the DV format of course...

To transfer from cam to PC and back to cam again, and keeping it as DV AVI use a free piece of software called WinDV - it's also very reliable and used by loads of people, so if you've any questions the answers will be in the guides and forums.

You'll need a firewire cable from the cam and into a firewire port on the PC - you may need a firewire card, these are pretty cheap and you don't need to fork out loads for a name brand.

You can capture from the cam to MPEG1 using a different type of card and other software - but, as you say, it's a lossy format.

As for DV being uncompressed - well, that's not quite true, although it is only lightly compressed and so, to all intents and purporses, can be considered an excellent source.

DV AVI is about 13.5Gb per hour of footage and is compressed at a bitrate of 25Mbps. I think uncompressed AVI is around 65Gb per hour of footage, though I'm not sure.

As a comparision, DVDs are around the 8 - 9Mbps mark.

I hope that sheds some light on things...