Intermittent flash frames/garbage in .m4v project render

[Sam Renkin]

I'm stumped and I hope you can help; my client needs a looping video for display on a kiosk at a franchise meeting. The file format I've decided on will be a 1280x720 .mp4 video that will loop in Quicktime on a PC connected to the 50" LCD display. Here's the problem I'm running into; the assets were given to me as .m4v files that were ripped from some DVDs using Handbrake. (Note: the source files were created internally by employees using a variety of video cameras and smart phones). The file size is actually less than SD (652x376) so I cannot size them up to 1280x720 without it looking like total crap. Since there is an "art" theme for the event, I came up with a simple solution; I found a stock image of a painter's canvas for the background, and a gilded picture frame that creates a smaller "window" for display of the video. I dropped the .m4v files into the timeline, used Pan/Crop to size them to the window, and I thought I was done. WRONG ...

There are some sync or display issues with these files that show up in the preview window and also in the final render. First, if I shrink the size of my preview window, the image disappears. This is annoying because I have 4-5 different video and audio tracks in the timeline, and I can't view them all and the preview at the same time. Second, when I render the file I get intermittent "flash frames" of diagonal lines of static garbage in a rainbow of colors. It happens usually near transitions in the video clips with sharp contrast, like a fade to black or up from black. One section that is supposed to be in black and white gets completely scrambled.

Could anyone shed some light on what's happening here?

[Sam Renkin]

Sorry, should have added my hardware/software setup. Vegas Pro 11, Core i7 w/Windows 7 and 8GB RAM.

[Sam Renkin]

Also, FYI the pixel size of the source files is 652x376, 624x368, 602x382, and 640x366. NO IDEA how they came up with these!!

[Edward Troxel]

When I've had to use odd files, I've often started a new project, set the properties to match the clip, and then render to a known good format (which is typically DV-AVI for me). Then I can use the new render and not have to worry about issues.

[Sam Renkin]

Thanks Ed - actually I've tried that with rendering new MP4 files, but the problem persists. Do you know of a situation where resizing the video using pan/crop would introduce this kind of issue?

You might know the answer to this question as well - my project output size must be 1280x720 because of the display media. So, is there a way to get these clips to appear at their native pixel size when I place them on the timeline? In other words, how do I keep Vegas from automatically enlarging them to fill the frame? I'd like to place them on screen in my project at their actual pixel size. Let me know?

Sam

[Edward Troxel]

Vegas will automatically expand them full size. I use the "Logo Resize" option in Excalibur to do this. It will resize and image back to it's original size on the screen.

[Seth Bloombaum]

Originally Posted by Sam Renkin

...actually I've tried that with rendering new MP4 files, but the problem persists...

MP4 can be a pretty poor editing codec. Choose a good D.I. codec like Cineform, DNxHD, Lagarith, etc. In this case, as Edward suggested, you're working at SD resolutions and smaller, so, DV-AVI would make an excellent editing codec.