pulsating 'blockiness'

[cyflyer]

Imagine a very low resolution video picture, full of large pixels. Now imagine a perfect picture. I had two vhs to dvd captures on the sony recorder where the picture was pulsating between good-blocky-good-blocky-good-blocky etc etc, at 1 second cycles. One began as such before clearing half way through, and another began good before it began this weird pulsating. Any ideas ? Something I'm doing wrong ? The video appears ok when being played, but does the stupids on the recorded dvd. Two coasters, so I'm apprehensive about carrying on.

[guns1inger]

This is usually associated with too much compression. How long are the videos ?

[ZippyP.]

You can get a higher bitrate by using a shorter recording time on your recorder. I never go more than 2 hours to get the best quality. What was your setting?

Noisy or poor quality VHS could be the problem as well, it will eat up bitrate and make it appear bit-starved. Perhaps a head cleaning or a different VCR might help.

[cyflyer]

gunslinger it was the standard two hours setting (124mins). Are there any conditions where this can change by its self during the recording ?

[cyflyer]

Still trying to make sense of this, and I think found something. At the beginning of this old b/w tape there are a few seconds of lead-in with b&w dots flashing, muck, whatever is the best way of discribing it. If the 'record' on the recorder is pressed during this 'mucky' period, the recording will pulsate 'blockiness' for the next ten minutes or so. If the 'record' is pressed during the normal steady playback, the recording is ok. Does this make any sense ? Is there something on the recorder that senses the stability or brightness of the vhs tape when the record is pressed, and reveiws after ten mintues, or I am just imagining it ?

Then again on one tape it started half way through.