HD Render to AVC/H.264

rtbond wrote on 4/6/2006, 8:42 AM

Hi Folks,

Using Vegas 6.0d. I captured 1080i HDV from my Sony HC1. Want to then render at same frame size using AVC/H.264. When using either the SONY or Main Concept AVC CODEC I seem to be limted to SD frame sizes, or smaller. This appears to be the case even when defining a custom template.

Am I missing something or should I be able to render a HD 1080 file using AVC?

Thanks!

--Rob

Comments

p@mast3rs wrote on 4/6/2006, 11:18 AM

Use Mainconcept and select Custom under Resolution and then input the HD resolution you want (i.e. 1280x720 or 1920x1080). :)

rtbond wrote on 4/6/2006, 2:46 PM

Yes, thanks I stumbled across this solution. I overlooked the "Custom" under the frame size in the Custom template.

BTW, given the HDV is 1440x1080, does it make any sense to specify a 1920x1080 frame size ("true" 16:9 1080i frame size), or when rendering should I be matching the HDV frame size of 1440x1080 of HDV?

Thanks!

--Rob

JohnnyRoy wrote on 4/6/2006, 3:51 PM

You could do either but make sure you match the pixel aspect ratio (PAR). HDV is 1440x1080 with a PAR of 1.3333. HD is 1920x1080 with a PAR of 1.0. It doesn’t make sense to render at 1920x1080 since your source is 1440x1080 (why waste the disc space?). Just make sure when you make a custom template using 1440x1080, that you change the pixel aspect ratio to 1.3333.

~jr

rtbond wrote on 4/7/2006, 9:58 AM

Thanks for the additional insight JR.

The Help associated with the pixel aspect ratio states "Choose the setting that matches your destination playback device " What is meant by "destination playback device"? (HDV recorder, BD or HD-DVD disc when available?)

Am I missing something (probably) as I understood you to advise setting it to match the PAR of the source (HDV) material, and not the destination playback device.

By checking the "Allow source to adjust frame rate" box in the custom template it grays-out the "Pixel aspect ratio" box. With the "Allow source to adjust frame rate" box checked, are you guaranteed the PAR will match that of the source material? (1.333 in the HDV case)

I appreciate your help with these concepts.

--Rob

JohnnyRoy wrote on 4/7/2006, 11:03 AM

If your target device doesn’t support the PAR of your source than what I said is incorrect. I assumed the target could support it which is a bad assumption. Yes, the documentation is more accurate. If your target only supports square pixels, then using a PAR of 1.3333 will leave you with distorted video. Use a PAR that your target can support and adjust your dimension accordingly.

~jr

bruceo wrote on 4/7/2006, 12:21 PM

I see a lot of FCP (maybe compressor or cleaner) encoded stuff on the web @ 640x 360 at a data rate of average 1.1-1.5Mbps. When i go into mainconcept and set custom framesize to 640x360 it automatically changes it to 640x368 and no matter how high the bitrate quicktime always reports the file as having 127.86Kbps so the others show a Mbps where I am showing a Kbps obviously significantly lower. Still shows 127Kbps even ifI set it to peak at 10,000,000 and average 2,000,000.

The video quality will be better, if I do the 2,000,000 vs the 768,000 but it reports the same 127Kbps data rate, but is no where near the FCP quality. the 2,000,000 is close in quality, but with an astronomical file size.

I have been using WMV which is ok, but for some reason shifts the midtones a little wam, where the h264 keeps the colors perfect and is much sharper.

What is the deal? Do I need to go to FCP?

rtbond wrote on 4/7/2006, 1:55 PM

OK thanks RK.

So if my display device is a 1080i HDTV/monitor, then I should set the PAR to 1.0, as the display device is square pixel based. Correct?

--Rob

JohnnyRoy wrote on 4/7/2006, 2:28 PM

> So if my display device is a 1080i HDTV/monitor, then I should set the PAR to 1.0, as the display device is square pixel based. Correct?

Not necessarily. A 1080i HDTV/monitor probably supports 1280x170p PAR 1.000, 1440x1080i PAR 1.3333, and 1920x1080i PAR 1.000. So the target device does support the native format of your HC1 camera and that is what I would use. Why waste disk space rendering 1920x1080 when your 1440x1080 is going to look just as good?

Remember if a device claims to be HD compatible, it should support all three resolutions. Even many of the native 1280x720p HD monitors will gladly accept 1080i input and convert it to 720p so it will still work.

~jr

rtbond wrote on 4/8/2006, 4:48 AM

Thanks for your continued patience JR.

So is it true that when rendering 1080i HDV source footage to a 1440x1080 frame size, a PAR=1.333 should always be used? I understand that HDV is inherently rectangular pixels, so I imagine rendering the same frame size with a PAR=1.0 would result in a distorted image. Correct?

Suppose my intented target playback device is a PC media player (e.g., QuickTime, Windows Media Player, etc) with a connected 1080 HD resolution-capable PC monitor. In this case would I have to render with a square pixel (PAR=1.0), 1920x1080 frame size?

Thanks!

--Rob