Archived from groups: alt.video.ptv.tivo (More info?
<firstname.lastname@example.org> wrote in message
> Is there a reason why a program would have a grainier picture when
> recorded on a tivo in best quality than a programe recorded on a DVD
> recorder at HQ? These are hooked up using the same cables and wires so
> it isn't the hook up. Is there some kind of filter or processer on the
> tivo that would cause a small loss of signal that a DVD recorder doesn't
> have? This difference is evident even when recording an external source
> like a camcorder.
The video signals may actually be grainy but the DVDR has a smoothing filter
whereas the TiVo doesn't really except for the RF in smoothing option. You
could try TiVo on HIGH instead of BEST. Also, VBR (save disk space) option
reduces some video noise. The early days of digital video produced very
grainy pictures that were eventually fixed not with higher resolution but
with smoothing filters because a blurry picture is more natural to humans
than a digitally noisy picture.
Also, when captureing previously compressed signals (miniDV, cable, digital
cable) there can be nasty interactions between the errors produced by the
multiple MPEG encoders involved. Digital cable is especially bad this way
because it gets recompressed 3x or 4x by the time you watch it (producer
analong or digital > sat distro > cable recode > TiVo recode > watching).
Not to mention the scaleing and rescaleing if you have an HDTV. Depending
on the settings used some combinations of encoders will produce more noise
than others. This doesn't automatically mean that each encoder is better or
worse but that the combination is bad. You can see the effect for yourself
if you take a high quality digital photo and decompress and recompress it 4x
and then rescale it a couple of times and then compare it to the orginal.
The TV, especially HDTV that we see is nowhere near the quality possible
because the distrabution channel is not well designed.