white streaks, black streaks, comets, dropouts

[jmac698]

I just wanted to post a reference, of a common problem in VHS tapes.
http://screenshotcomparison.com/comparison/111412

1 White streaks, descriptively called comets (like the white streak of a comet across the sky), also called dropouts, which is a proposed functional description of why they occur. These little white lines appear throughout the video for at least two reasons. One reason is just radio interference from a motor, computer or other device, either when capturing or when it was recorded. If it was recorded onto the tape, it has to be removed with video filtering. You can tell it was recorded (or 'baked') into the tape by capturing the same spot twice and verifying that the noise is in the same place.
The other explanation is what people call dropouts. In this case the noise appears iin different spots. You can remove with filtering, but even better, if you capture three times, you can recover exactly the original video simply with the "median technique".

2 Black streaks. These occur usually the same place on each playback. I have noticed it can occur when playing an SVHS tape in a non-SVHS VCR. This can happen with hi8 tapes in video8 playback as well (I believe). It tends to start when going from dark to light video, from left to right. Instead of the light video, there is a short deep black streak.

In both cases you can try yup's filters, but anyhow move your post to Restoration and ask how to fix "comets" or "black streaks".

I just hope this post helps you identify the types of noise.

yup's filter
http://forum.doom9.org/showthread.php?p=1563121#post1563121

[mammo1789]

2 Black streaks. These occur usually the same place on each playback. I have noticed it can occur when playing an SVHS tape in a non-SVHS VCR. This can happen with hi8 tapes in video8 playback as well (I believe). It tends to start when going from dark to light video, from left to right. Instead of the light video, there is a short deep black streak.

You are absolute right especially about hi8 tapes checked myself and its confirmed.
Maybe easier will be to recapture using hi8 or 8digital camera but they are very hard to find, I find yups script too softening my tape for instance but maybe something changed till then.
Do you have some yours examples of hi8 black streaks that were removed i will really like to see them thanks jmac

[jmac698]

The example posted shows both problems on the right image. The left image shows them removed with median technique.

[mammo1789]

I got some error running script jmac any though

[jmac698]

ask yup, or start a new thread under Restoration.
And you are missing some pluign.

[mammo1789]

I found it it was the version number of removegraint ( all that versions ) its working now but still it blurs a lot. I tried multiple passes as his suggestion with lower values, and its still very blurry i will try descratch and despot route to see if there is any improvement

[mammo1789]

I uploaded short clip mjpeg with problems http://www.mediafire.com/?uz148p9dyky999z ( i do the same to doom9) when you have time can you look at it and suggest what to do
Thanks jmac