codec question

mcgeedo wrote on 1/28/2003, 2:09 PM

I am using USB Instant DVD to capture from analog. My output will be to DVD. The question is, is it better to capture using a higher codec rate than I will render to, or does it make no difference.

Capture 4 Mbs/sec ->> Render 4 Mbs/sec
or
Capture 5 Mbs/sec ->> Render 4 Mbs/sec

Other than render time, will there be any difference?

Thanks,
Don

Comments

mikkie wrote on 1/28/2003, 2:29 PM

Welllllll... Yes. You want the highest data rate your system can manage easily.

mpeg2 is a lossy codec, meaning that it throws out some of the original picture. If you capture at a higher data rate, then you have more information to edit and recompress. So yes, a higher bitrate helps, bearing in mind that at some point, as you increase the data rate your system might start choking on you, & you'll start to drop frames making things much worse.

If you can control the mpeg2 settings, it's also best to capture all I frames as this will generally give you a better video after editing/recompressing. It is more hard drive intensive, so again, if you start loosing frames or quality, move things back.

RE: output to DVD, depends on how much you want to squeeze on your DVD. I think the spec goes to about 9, but no sense rendering any higher then you can capture. In the other direction, & Depending on your subject matter & how clean your video is, *might* be able to get closer to 2.5 or 3, letting you get more video on your disc. You maybe could get lower still but capturing to mpeg2 is limiting you now.

mike

mcgeedo wrote on 1/28/2003, 2:41 PM

Thanks, Mike,
That kind of confirms what I thought. I am pretty much limited to about 4 Mbs/sec on the DVD in order to get all the material I need on 1 disk. I have no issue capturing at 5 (as far as dropped frames), but just wondered if I was just wasting time/space in doing so.

Thanks again,
Don