Aspect Ratio Help! 1.3 vs 1.0 and conversion from .m2t

[Bman.]

Good afternoon folks-

I am having some issues with aspect ratios and trying to get them to convert correctly.
I have an HDR-HC7 HD camcorder (output is an .m2t)

The output as far as I can tell = 1440x1080 (1.3 ratio) from the camera.

I have converted the raw .m2t down to 720x480 (clicking the 1.3 ratio on the output template) through Vegas and have begun to manipulate the file in Movie Maker. The problem I am having is that the output from Windows Movie Maker doesn't provide a final product that matches the resolution of the source file. The .wmv that renders from Vegas looks correct..

Soo...

I have downloaded the WM Encoder to try and make a profile. I have made the profile but I can't get it to show up in the Template list when ready to render. Where do these .prx files need to go?

I have got it to work before going from the HD Camcorder to Vegas to Movie Maker but for what ever reason now the output of what I am doing doesn't match the raw .wmv coming from Vegas.

What am I doing wrong? I have confused myself beyond repair...

I am obviously missing the fundamental understanding of the .m2t to .wmv conversion. Does any one have advice on the correct ratios I should set everything to get the output to render correctly?



Bman.

[minidv2dvd]

it's an HDV cam. 1440X1080 non-square pixels with an equivalent square pixels format of 1920x1080. set up the project properties to HDV then import the files.

without you telling us what the final export format you want is, can't help any further.

[Bman.]

Thanks for the response. I am finding its harder to find answers than I would have imagined when it comes to video editing. At least in the circle I run in.

To answer your question - the final format I am looking for is a .wmv file that is both HD and without letterbox. I think I have got it working but I don't understand.

For example, Motion Picture Browser says:

Image = 1440x1080
Aspect Ratio = 16:9

So, does that mean that the letterbox at the top and bottom are recorded into the video as 1440 / 1080 is not 16:9... rather 4:3.

I get confused when I get to Vegas and render out the video to a .wmv. I am rendering it to 1280x720, 16:9, with the pixel ratio of 1.0.

...with that rendering the letterbox at top and bottom are gone and ultimately the rendering from Movie Maker at 1280x720 works well and appears to have no stretching etc.

So... I think I need a lesson in math and ratios. I think it's the 1.3 pixel ratio that is throwing me off. I get that 1440*1.3 = 1920... but why the 1.3 factor from the camera in the first place? Further more, I don't understand why when I render to 1280x720 it works at a 1.0 pixel ratio works.... if I kept the ratio at 1.3 and rendered 1024x768 would I end up with no stretch also...

The last question was regarding the .prx file extensions. These are profiles used by Movie Maker - I make a new profile but I can't seem to get it to show up in the render / save as template formats.

Thanks for your help.

[minidv2dvd]

pixels come in lots of different shapes. the most basic is square - 1.0, but HDV pixels are rectangular, wider then they are tall in a 1.3333 ratio. so converting 1440 wide pixels to square pixels results in 1920 square ones. other formats use different ratios. some use more than one, as in one for 4:3 video and another for 16/9 widescreen. the video usually contains a "flag" to tell the decoder how to process it, but not always.

so both 1440 and 1920 by 1080 video can represent exactly the same thing. 1280x720 is a smaller 16/9 that would also be the same. 1024x768 would not. 864x480 would.

can't offer any help with movie maker sorry.

[Bman.]

I see - so, if I left the rendering at a 1.3 ratio... then 1024x768 would yield the same result in terms of aspect ratio of 1440x1080...I think. Both a 4:3.

If I understand - that's why there are letterboxes at top and bottom of the raw .m2t file.

Thanks - I think I am making headway

[minidv2dvd]

no - because when you render out of HDV, you want to render to 1.0 square pixels. only HDV is in 1.3333 wide pixels. so rendering to 768 vertical would need a horizontal of 1366 to remain the same 16/9 aspect ratio. 1280x720 is a popular 16/9 widescreen size.

[minidv2dvd]

also there is no letterboxing in raw HDV video. if you see letterboxing it's because the player isn't decoding it correctly.

[Bman.]

I see - so always go to 1.0 square. Why would I want to do that fundamentally, just so conversions down the road don't get out of control?

Regarding the viewer, you are right. I was able to go windows mode and adjust the view and the box was just "left over" when in full screen mode.

Thanks again- I am going to print this out so in 6 months down the road I will remember.

Benjamin.

[minidv2dvd]

the important thing to remember is to convert to the native pixel aspect ratio of the destination format. like for dvd mpeg-2 a widescreen 16/9 movie is 720x480. i'll let you ponder that pixel aspect ratio.....

[jagabo]

DAR = PAR * SAR

DAR = display aspect ratio, the final shape of the picture
PAR = pixel aspect ratio, the shape of individual pixels
SAR = storage aspect ratio, the frame dimensions

For example:

4:3 DVD:
DAR = PAR * SAR
4:3 = 10:11 * 704:480
4/3 = 10/11 * 704/480
1.333 = 1.333

16:9 DVD:
16:9 = 40:33 * 704:480
16/9 = 40/33 * 704/480
1.778 = 1.778

4:3 Square pixel:
4:3 = 1:1 * 640:480
4/3 = 1/1 * 640/480
1.333 = 1.333