Editing h.264 mp4's in vegas

[Alexander Peerman]

Hey guys,

i've just got the samsung hmx 20c which record 1080/50i and 1080/25p, i'm using it to film lots of acrobatics and so have worked out 50i is the best way to film in. It records to mp4 format.
I eventually worked out that if i drag my clips onto the timeline and render them out to 720p avi's they are in a format which are smooth to edit.
Would there be any alternate ways of editing with the mp4 format ? I'm mainly going to be uploading files to youtube and vimeo for people to watch so am only going to need to stick to 720p, which seems to come out quite nicely, like this test file 10bps 25 fps 720p mp4 on Vimeo

I'm also getting lines across footage with lots of movement in it... which seems to show up on the youtube video - http://uk.youtube.com/watch?v=wM9gg6ahgLo...

is this something to do with bitrate, shutter speed on the camera, variation in focus ? or just the way the video is streaming from the web ?

I hope you guys can help out !
Thanks !

[Ken Steadman]

I get this too on uploads with lots of movement on vimeo too; I assumed it's their encoding but I could be wrong.

[Douglas Spotted Eagle]

Have you tried rendering to double PAL/50p for your initial work render? Using an offset by 1/2 frame with two copies, top set to 50%?

This *sometimes* helps. Old trick, but a goodie, especially when remapping time.

[Allan Black]

So Spot, you're kinda filling in the interlaced frames to get a quasi 24P?

Cheers.

[Alexander Peerman]

Originally Posted by Douglas Spotted Eagle

Have you tried rendering to double PAL/50p for your initial work render? Using an offset by 1/2 frame with two copies, top set to 50%?

This *sometimes* helps. Old trick, but a goodie, especially when remapping time.

Oh that sounds good. I'm not completely familiar with rendering to double PAL...

When i've rendered the mp4's down to 720p avi's i think there may also be a little bit of a problem with slowing down footage... Is this common ?

[Douglas Spotted Eagle]

Originally Posted by Allan Black

So Spot, you're kinda filling in the interlaced frames to get a quasi 24P?

Cheers.

24p? No. It's still 50i/25p. No re-sampling of frames for cadence is taking place, but rather, you're giving the frame blend a better image to flatten from i to p. If it was shot 50i to capture motion, all you're really doing is a psuedo field doubling (like hardware devices do).
It's a kludge, but a kludge that works fairly well, especially in those situations where you wish you had more frames. Slo-mo and progressive is very hard to shoot at low framerates if the subject has a lot of movement. 24p, 25p, 30p can be challenging, especially at the low shutterspeeds used on small chip cameras that are hungry for light.

[Alexander Peerman]

HI douglas, i've tried exporting to 24p but seem to get loads of trails on movement eg - YouTube - 7bps 24fps 720p

[Douglas Spotted Eagle]

I'm not sure why you're going to lesser frame rates vs greater frame rates. the 50p for working source is mor than double 24p, and the eye can't discern 24p from 25p at delivery anyway...What is the reason for reducing the number of frames?

[Alexander Peerman]

whoops my bad, guess i'm not aware how to render to 24p properly, got more testing to do over the weekend.