Missing Part Of Picture In Recording

[TerryHau]

When i'm watching the broadcast directly the image is fine, but if i record, and then watch the recorded file, theres a small piece of the picture missing at the top.

I attached an example. You'll see, most of the top few lines are missing.
Anyone know how to fix this.

In the second example, this time, theres a bunch of garbage pixels at the bottom left.
Again, this dosn't happen when i'm watching the actual broadcast. Only in the recorded file.

All my recordings are ruined by this jagged corner right in the top center of the video.

(you might have to zoom in to see it better)

edit:

http://www.cse.unsw.edu.au/~thau627/test.jpg

http://www.cse.unsw.edu.au/~thau627/test2.jpg

[siddharthagandhi]

You're better off hosting it at ImageShack or the like. Attachements require moderator aprroval, and that can take days.

[TerryHau]

i've figured it out.

The black bar and white dots are part of the broadcast
It seems my dvb software overscans quite a fair bit of the video during live playback. Which is why i normally don't see it unless its recorded and played back.


So i've got another question.
I have a bunch of episodes of a tv show already encoded into xvid, and don't have the original dvr-ms anymore. They all have that black bar. Is it possible to just crop the video, without reencoding and loss of quality?

[siddharthagandhi]

I'm not entirely sure about this, but to my knowledge there isn't a way without re-encoding.

[Blue_MiSfit]

If you use ffdshow to decode, what you can do is run a crop on playback. It should be fast enough... Just go into the ffdshow directshow video decoder configuration, click the checkbox next to crop, and specify the paramaters. Everything should go well. Some of my south park episodes have this same problem, overscan bullshit that I forgot to deal with before encoding.

Without ffdshow, not sure how to do it :)

To permanently remove the overscan, you will have to crop and re-encode.

Good luck!

~MiSfit

[siddharthagandhi]

The same thing is possible with Nero Showtime, but the likeliness of you having that is slim and ffdshow is free so go with blue msfit.

[TerryHau]

Thank's ill try cropping during playback.
For future encodes, i'd like a little advice on cropping. Cropping two lines off the top seems to be enough to hide the problem. But then i end up with a resolution thats not 16:9. Whats normally done here. Do i crop off some from the sides as well, then size the whole thing up, or just add a 2 pixel black border on the top to keep the same resolution/ratio. Or should i just leave it as an irregular resolution.

[siddharthagandhi]

You could crop and then letterbox in some encoders, and you can also fix this in an avisynth script, but I'm not too smart at that.

However if this is just for computer playback then it shouldn't matter what aspect ratio/resolution you have.