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clearly something about pixels I don’t get…
Posted by Griff Hamlin on September 6, 2013 at 12:57 amI have this footage (WMV, square pixel, 720×480.) Clearly it has more pixels wide than 640, and clearly it has more pixels high than 360.
Yet, when I bring it into a Vegas Pro 12 project with the Project properties on “internet 360p” and I uncheck “Adjust source media…” it still letterboxes it and obviously makes it smaller to fit.
That isn’t what I expected and I thought that the footage would overspill the boundaries of the output frame since I unchecked that box.
What am I missing here? Is there any way to import a larger file onto the timeline and just have it get cut off instead of having it resized to fit?
John Rofrano replied 12 years, 8 months ago 4 Members · 7 Replies -
7 Replies
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Kelly Griffin
September 6, 2013 at 1:31 amYo Griff–
I’ll betcha donuts to pesos you just have a pixel aspect (shape) issue. The 720×480 frame size is NOT usually square pixel; NTSC standard def TV was in the world of non-square (i.e., taller than wider) pixels.
What that means/meant is/was that if you created an image of a circle that looked correct on a TV display, if you did a frame grab and looked at it in Photoshop that circle would look like a wide oval (and a person would look thick). The 640×480 frame size is a square-pixel compensation (without enlarging either axis) for the difference in aspect.
That doesn’t explain (to me) why you have 720×480 square pixel footage in the first place, but I wonder if your content actually does appear stretched horizontally (?)
–K
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Griff Hamlin
September 6, 2013 at 3:17 amYup… I know it’s an oddball size, but it’s for real.
This is output from a Roland VR-5 and ends up in a WMV file… kind of a pain in the neck actually. But the VR-5 is so stupid easy to work with other than that I’m hoping to work this out.
I guess I’m too used to still photos. If I have a photo that’s 720×480 I know how to crop it to 640×360 without any loss of quality, just a loss of pixels.
I would think I could do the same thing with Vegas but I can’t figure out how.
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Kelly Griffin
September 6, 2013 at 3:22 amIf you want to send me a couple of seconds of the clip (OOPS “video event”) I’d be happy to look under the hood for you.
–KG
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John Rofrano
September 6, 2013 at 1:02 pm[Griff Hamlin] “I guess I’m too used to still photos. If I have a photo that’s 720×480 I know how to crop it to 640×360 without any loss of quality, just a loss of pixels.”
I don’t believe that you want to crop. It appears that the Roland V5 is incorrectly converting what should be 720×480 PAR 0.9 to 720×480 PAR 1.0 and Vegas Pro is trying to correct that error. In other words, cropping would loose valuable information that is incorrectly distorted as 720×480 PAR 1.0, and stretching it back to 655×480 PAR 1.0 or 720×480 PAR 0.9 is what you really want.
You must understand that Roland made an unfortunate choice when they chose to deliver WMV because WMV does not support Pixel Aspect Ratios and Broadcast TV does! They should have delivered a proper 655×480 PAR 1.0 WMV file which would have accurately represented the original 720×480 PAR 0.9 broadcast as PAR 1.0.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Griff Hamlin
September 6, 2013 at 3:39 pmIf that is the case, John, how would I go about doing that sort of conversion to PAR 0.9?
Here is the media info on the file if you want it:
Here is the mediainfo from the source material:
Format : Windows Media
File size : 47.5 MiB
Duration : 1mn 21s
Overall bit rate mode : Constant
Overall bit rate : 4 878 Kbps
Maximum Overall bit rate : 6 294 Kbps
Encoded date : UTC 2013-08-08 17:20:57.820Video
ID : 2
Format : WMV2
Codec ID : WMV2
Codec ID/Info : Windows Media Video 8
Description of the codec : Windows Media Video V8
Duration : 1mn 21s
Bit rate mode : Constant
Bit rate : 6 000 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 3:2
Frame rate : 29.970 fps
Standard : NTSC
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.579
Stream size : 58.4 MiB
Language : English (US)
NumberOfFrames : 2431Furthermore, when I’ve done that, what’s the best way to cut off 60 pixels from the top and bottom (roughly) to make it 640×360 instead of 655×480?
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Stephen Mann
September 6, 2013 at 4:14 pmKelly: It is a clip. When the clip is represented on the timeline it’s an event. Clips are physical media, events are pointers to the media clips on the timeline. You can have many events pointing to the same clip.
As an example, I recently CG’d a hundred black balloons floating up into the sky for a film that a friend is making. I started with one image of a balloon. But there’s a hundred events from that single image of a balloon on the Vegas timeline. I used event FX and keyframes to make many of the balloons look and act differently in the video, but the clip of the original balloon is unchanged.
Since I am exclusively Vegas, I am curious how this could be done in AE or other editor?
If you are familiar with Photoshop, an event is to the clip in Vegas as a smart object is to the original image in Photoshop. In neither case do you ever edit or modify the original media or image.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
John Rofrano
September 6, 2013 at 5:21 pm[Griff Hamlin] “how would I go about doing that sort of conversion to PAR 0.9?”
Here is something to try:
- Create a new project using the stock NTSC DV (720×480, 29.970 fps) template which has a PAR of 0.9091.
- Drop a clip into the timeline and answer No if Vegas wants to change the project properties.
- Right-click on the Event that the clip creates and select Properties…and then the Media tab
- Set the Pixel Aspect Ratio to 0.9091 (NTSC DV) and click OK
That should correct for the fact that the original media had the wrong pixel aspect ratio.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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