need help on recording length of TV captured card

[ksky213]

i have a question regarding these TV capture card. When i try to record VHS in to my hardrive it takes up about a 700mb just to record 10-15 min of tapes. For a DVD i can only record up to about an hour long of tapes. I see some people can compressed the files and prolong the recording length for a CD about 4hrs long and for a DVD about 25 hrs long.but it can only be viewed on the computer. it is a real media VBR file i think?! how can they do that? What kind of software do they use?................ thx alot

[SaSi]

How much video duration can fit on a CD or DVD is a direct function of the bitrate used. The higher the bitrate, the shorter the video. The lower the bitrate, the longer the video length.

Lower bitrate, generaly, means lower quality.

Quality can be "reduced" in ways that they don't really sacrifice it.

Standard "DVD quality" video attributes mean a resolution of 720x576 or 480 for NTSC.

Reducing that to the Video CD resolution (352 x 288 or 240) gives room for 4 times as much video duration using 1/4th of the original bitrate (since the frame size is 1/4th of the original).

A 3 hour movie can be made to fit on a 4.36Gb DVDR with careful encoding. Encoded at 352x288, this makes space for 12 hours of video.

Image clarity and detail is somewhat lost and it depends on each person's taste and priorities to choose.

An analogy with VCR is the SP vs LP vs EP settings. SP is much better and clearer than EP.

[teegee420]

I don't know where you're getting your numbers from because I've never seen a cd with 4 hours of video and a DVDR with 25. I'm sure the quality was less than stellar.