I’m replying to this thread because I just encountered this. The 576 number comes from the vertical. For some reason X is using the vertical of the frame as the allowable horizontal crop limits. Obviously the horizontal should be permitted to crop all the way across the frame from left or right. The vertical crop limit is the same as the horizontal. Check it out in a 1080p project. The horizontal crop is only allowed to be …. 1080. Yes, some engineering moron made a typo and is parsing the vertical for both the horizontal and vertical crop limits.
What’s worse, is I discovered that in going from 7 to X via XML and 7toX, the crop value is actually given via XML as a percentage. Which makes sense because you don’t always know what the frame size is. So all the horizontal crops from 7 come out too wide, because X is doing the math as a percentage of 1080 instead of 1920. Genius.
I had created a mosaic of lots of pics, each in it’s own nest and the nest then cropped. 40 nests on the screen at a time. I thought I’d bring it into X to see if it would render faster since 7 was going to take 3 hours for 3 minutes. It would’ve been perfect if not for this horizontal crop bug. The good thing is I had about 200 compounds in a single sequence and X handled it no problem. Of course in 7 I could barely scrub or move an image without waiting. 40 layers of stills in compound clips and it plays back in full 1080p rez without dropping a frame.
It must be a recent bug, because I often crop text on left to right to reveal a word or bullet point. Pretty sure I was doing that with some bullet points in October/November. Can anyone check 10.0.9 to see if this bug was there? On a 1080p project, one should be able to crop (trim mode) the full frame of 1920 pixels either left or right and not be limited to 1080.