Breathing/pulsing MPEG..

[OasisPlaces]

I'm using TMPGENC to make VCD's SVCD's CVD's..
I've been using mpeg 1/2 for quite along time as
a final format.. but most of my source has been off
Video tape.. Lately I've started using digital source..
at lower bitrates 1900-2100ish..

I've started to get this pulsing effect on the video streams
It seems directly related to the quality of the source..
the better the quality of the source the worst this
effect is.. it's especially miserable in dark, and grey
video sequences..

It almost seems as though the I frames are too good quality
compared to the PB frames.. so whenever the stream hits
an I frame the picture sharpens alot.. then you get
this rythmic breathing effect..

anyone ever see this, and find a way to fix it?????

[Frank Marshall]

Just a thought, if you've set the key frame to something like one second, you can end up with video that seems to flitter rhythmically (every second/every key frame). This would be especially noticeable on still, long (duration) shots. The solution is simply to set the key framing in your encoder to something like 5 or 10 seconds, depending on how long your motionless long shots are.

[Flying dutchman]

Do you use CBR, VBR, CQ?
If you use VBR or CQ, set B and P frame degradation to 0%.

For PAL sources set GOP length to 12, for NTSC set it to 15.
(Rule of thumb: 2 GOP's per second)