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View Full Version : DV vs. uncompressed avi


yawnmoth
29th January 2003, 23:31
uncompressed avi is a pain to capture, because it is very hardware intensive... every time i try to capture it, i get a lot of dropped frames, etc. and plus, it gets huge, fast, and it soon passes the 2gb file size limit for windows, and bleh. i don't like uncompressed avi.
Anyways, based on my understanding of DV, it employs hardly any compression... would i still get dropped frames with DV? how long before i would pass the 2gb file size limit for windows?

bb
30th January 2003, 08:16
DV is compressed using an algorithm which has some similarity with MJPEG (e.g. using DCT). It compresses 5:1 at a rate of about 3.6MB/s. That implies you get about 9.5 minutes of DV video into a 2GB file. But the filesize should not be a problem, because capture programs can split after 2GB, and VirtualDub as well as AviSynth can deal with segmented AVIs.

Another option of not using uncompressed AVI is Huffyuv lossless compression (ratio ~2.5:1) or MJPEG (ratio depending on quality setting, typically 10:1 or even more).

bb

yawnmoth
31st January 2003, 00:31
is the 3.6MB/s megabytes or megabits? I currently have a Hauppage WinTV PVR-250, and usually capture at 4mbps CBR. this card does it in megabits, though. so my file is 275 megabytes on the hard drive for 8.5 min.

bb
31st January 2003, 07:28
It's 3.6 MegaBYTES, not Megabits, per second. Your Hauppauge WinTV PVR records in MPEG-2 as far as I know, at a much higher compression ratio than DV. Unfortunately MPEG-2 is not good for editing, whereas in DV files every frame is a keyframe, so you can easily edit.

bb