Auto Cropping and Vertical lines - a warning

[cbud]

I thought I would post this so everyone is aware.

When encoding video with an aspect ratio of 4:3 there is sometimes (esp TV Shows) 2-6 pixels of black space on each side. Handbrake will detect this and crop it off. Sometimes this cropping will decrease the width of the video, so instead of 640 it will become 624. When this happens, thin (1-2 pix) light colored lines might be seen on the sides of the video. These lines are very difficult to notice in QuickTime or on a iPod, but once displayed on a WS HDTV (at 4:3) they are very noticable and slightly distracting. I think they happen when the picture's width or height is not divisible by 16, which might occur if you crop. This might also occur with 16:9 content, but I have not noticed it yet.

I recommend that one does not crop 4:3 video unless it is really needed. Leaving a few black pixels on the side is not a big deal compared to the light lines. I have noticed this happening with MASH, Scrubs, and Voyager. Additionally, cropping can also lead to a slightly messed up aspect ratio.

[hawkman]

Sure you're not just noticing artefacts already in the source material? I tend to find that DVDs with black borders have the first couple of pixels of picture a bit weird and lighter-coloured, too - I crop them out along with the border.

[cbud]

I know what you are talking about, I crop that too, but no, that’s not it. I have re-encoded a few of them without cropping and I don't get them. I think the size of the video can change from title to title. One title the black bars will be 6 pix then the next it will be 4. Auto-crop works well on some, but others it messes up the aspect ratio. On some episodes of Scrubs everybody looks thinner and tall, then I play the next episode and they are back to normal. The light lines ussually coinside with a messed up aspect ratio. Mind you, all this is very subtle and hard to notice, but its there.