Crop without re-encode?

[rumplestiltskin]

I know I've seen this question a hundred times but I just can't remember the answer:

I have an MP4 (H264/AAC) with 40 pixels of white at the bottom of the frame. I'd like to crop out those 40 pixels without having to re-encode. Is there an app for this (preferably a free app)?

I do have the original AVI. I opened it in QT Player Pro, shifted the VOBSUB down 40 pixels (because the subtitles were appearing too high) and exported to the (H264/AAC) MP4. That's where I am now.

Thanks for any advice.

[Baldrick]

I have an MP4 (H264/AAC) with 40 pixels of white at the bottom of the frame. I'd like to crop out those 40 pixels without having to re-encode. Is there an app for this (preferably a free app)?

It's not possible.

[Case]

You could have cropped in QuickTime Pro by using a 1-bit (black/white) mask, before exporting.

[rumplestiltskin]

You could have cropped in QuickTime Pro by using a 1-bit (black/white) mask, before exporting.

Now that piqued my interest. Could you be a bit more specific or point me to an instruction set somewhere? I don't mind doing the export all over again if the crop can be accomplished at that time.

I'm wondering (and this is a different approach) if I could extract the VOBSUB (again, in QT Pro), crop that, and then paste it back into the AVI and position it; then do the export to H264/AAC?

[Case]

Could you be a bit more specific?

Make a new image document of the exact frame size of your movie in pixels. Make the area to crop white and the remainder part black. (If you do it the other way around, that won't really matter, as you still can invert the image in QuickTime Pro.) Save in a lossless format, such as .png or .tif, (not .jpg).

Open you movie file in QuickTime Pro. Show Movie Properties (Cmd-J). Select the video track. Select Visual Settings. On the left, Choose a mask file. Select your black-white image. The mask will be applied to your movie window instantly. (Use the Invert button if you erroneously switched the black and white areas.) Close the Properties window. Export.