Analog capture vs Firewire

Spirit wrote on 12/8/2002, 6:31 PM
I have been doing all my capture as analog. I use an Osprey 210 analog capture card which has worked very well, but the downside is that I must specify a compression codec while capturing, frame rate etc and this can sometimes lead to mixed results depending on a how I render the project in VV3.

I'm wondering if I process the video through a DV camera and capture via Firewire then is this a more "pure" capture ?

What I want to do is reduce the generational decay of the source since I currently compress at capture; compress with VV3, then compress again for streaming as an swf video file. If the capture file is better then I think my results (and editing flexability) may improve.

Any thoughts ?

Comments

Erk wrote on 12/8/2002, 6:59 PM
What kind of media is your source video on? Do you have a digital camcorder with analog inputs, like a Sony Digital 8? If so, you can use the camera as a digitizer in real time.

G
Spirit wrote on 12/9/2002, 3:41 AM
I don't have digital camera at the moment, but I'm thinking of getting one for this reason. I'd certainly get one with A/V in/out.

But what I'm really wondering is whether Firewire capture will give me a "raw" capture file. Er... maybe I'm not being terribly clear ?
Erk wrote on 12/9/2002, 7:00 AM
Spirit, I think I know what you want, ie., to get video in your machine, and work with it there with the least amount of compression, before compressing for final output. As far as I know, uncompressed video is rarely captured, because the file sizes are so huge (even with today's big/cheap drives) and editing is slow. That's why the DV codec is pretty standard. But for smaller projects, I guess some might capture uncompressed, like the above comment.

If you digitize your analog video with a camera, the camera (or some other converter) is compressing it to standard DV. Firewire technically is not "capturing" (in terms of doing the compression) but is really just a very fast bit-for-bit file transfer protocol (with some device control and power signals as well).

Once you've got DV video in Vegas, you can edit without worrying about perceptible quality loss, because the DV codec Vegas uses is considered the best around. The compress for final output.

More knowledgable folks can jump in here and correct me on the technical details, but I think this is the gist of what we're doing.

G
Spirit wrote on 12/9/2002, 7:35 AM
Yes, thanks for the information. The only reason I'm thinking of doing this is because with analog capture I'm forced to choose a codec for capture compression eg: yuv9 etc. Depending on whether the final file is intended for web-swf video streaming or just CD-based AVI/WMV veiwing, the original acpture codec can effect the final output because of the acculmulation of compression codecs.

I suppose what I'm really asking is whether direct digital capture is a "cleaner" capture.
HeeHee wrote on 12/9/2002, 4:45 PM
Spirit,

Yes, DV capture thru firewire is a cleaner capture than using analog and a compression codec. Rarely if ever do you get dropped frames. the quality difference between DV and uncrompressed is marginal.

One thing to consider is to get an analog to Digital converter like those offered by Canopus. You can then hook up your current analog camcorder to it and it will convert to DV on the fly. The best thing about it is that it locks the audio to the video. Many analog capture cards can lose sync on long captures.

-HeeHee
Bhendrix wrote on 12/13/2002, 12:50 PM
DV format is somewhat more compact than Raw capture of Analog Video. That is why it is beneficial to pass the video thru a digital camera for capture.

I personally prefer to capture analog as MPEG2 because I almost always plan to put the video onto a DVD. It also saves me an intermediate step when I burn the DVD because I don't have to wait for a software conversion to MPEG2. However, you have to have the MPEG2 plugin for Video Vegas to work with this video. I use the PCI VideoOh! device from Adaptec to capture directly to MPEG2 format. It goes for about $149.