Rendering PNG

[Neil Hynes]

Thank you John. I understand what you are saying. Basically, import my image with the correct dimensions created in Photoshop in the 1st place avoiding adjustments/distortions in the program. So that means go back to Photoshop and re-work the file with the 1920 width and however long I need it, and with the spacing I like, and then bring it into Vegas where Ill only need to Key-Frame the scroll. Simplified, thanks!

I see now that the error was in my preparation. Quick question though; why does this only become corrupted when I rendered in PAL SD MPEG2 and seems fine in 1920 BY 1080 MP4 Is it becasue there are too many pixels to deal with for PAL SD render ?

Again, learning as I go thanks to you guys.

[John Rofrano]

[Neil Hynes] “I understand what you are saying. Basically, import my image with the correct dimensions created in Photoshop in the 1st place avoiding adjustments/distortions in the program. So that means go back to Photoshop and re-work the file with the 1920 width and however long I need it, and with the spacing I like, and then bring it into Vegas where Ill only need to Key-Frame the scroll. Simplified, thanks!”

Exactly! you got it.

[Neil Hynes] “Quick question though; why does this only become corrupted when I rendered in PAL SD MPEG2 and seems fine in 1920 BY 1080 MP4 Is it becasue there are too many pixels to deal with for PAL SD render ? “

I’m guessing it’s because PAL doesn’t use square pixels and when Vegas resizes it does the calculation wrong because your aspect ratio was distorted by the crop. The trick is to keep the aspect ratio the same or better yet, not have Vegas resize in the first place. Then everything will fall into place.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Bob Peterson]

For a 720 x 480, which was my example, the png width should be any multiple of 655. The length can be as large as you want it to be. Then, as John pointed out, in pan/crop you set it to match the output aspect. It will then not be distorted when it is displayed. The factor which tells you what the png width should be is the pixel aspect ratio. For a 720×480 NTSC image that ratio is .909, so .909 times 720 gives you a width of 655. You simply have to determine what the aspect ratio is for the video file you will be rendering.

The reason for this is that pngs use square pixels which are a bit larger than the pixels used in video. Thus, the image is a bit wider for the same number of pixels.

[John Rofrano]

[Bob Peterson] “The factor which tells you what the png width should be is the pixel aspect ratio. For a 720×480 NTSC image that ratio is .909, so .909 times 720 gives you a width of 655.”

It’s important to note that Neil is working with PAL SD Widescreen which has a Pixel Aspect Ratio (PAR) of 1.4568 so his PNG’s would need to be 1049 x 576 if his project was PAL SD Widescreen.

It’s also important to note that PAL SD Widescreen has a 1:82:1 aspect ratio while HD is 1.77:1 so PAL SD Widescreen is actually wider than HD 16:9. So something will need to be either cropped or stretched to satisfy both formats.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Neil Hynes]

Thanks again guys and thanks John for the file prep advice; couldnt have said it better.

[John Rofrano]

You’re welcome Neil. I’m glad we could help.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Bob Peterson]

Good points. That is why I was stressing that he needs to use the aspect ratio of the format that he is rendering to. I did not want to leave the impression that everything has the same pixel aspect ratio. I did want to suggest that, once you figure out and confirm what you need in Photoshop to match the pixel aspect ratio for the desired render format, things become a LOT simpler.