how long can i record on a dvd dl at sp & slp?

Question

pretty self explanitory

Answer 1

You should read your manual because there is no standard.
Every manufacturer uses its own settings. In most cases, for normal single-layer DVDs they try to match the VCR settings: 2 hrs, 4 hrs, and 6 hours. It is all about bit rate and capacity. Say you record at 6 Mbits/s (common SP setting), then on a 7 GB (DL) you can record for about 3 hours :

Math: (7000*8)/(6*60*60) = 2.59 (There is audio as well, so this is approx.)

If SLP is about 2 Mbits/s (VCR-like quality), then it should be close to 9 hours on a DL disc.