choppy hdv

qazwsx

qazwsx

Well-known member
i'm having a little problem with choppy hdv playback. i downloaded some canon 24f xh-a1 sample footage in .m2t and when i play them in the timeline, they're fairly choppy even in draft quality. the timeline is set to the default 1080 24p template in vegas 7c. however, when i re-encode some hd wmv files to hdv/m2t/1080/24p, they play as smooth as butter. what could the problem be? could it be because the canon sample footage wasn't originally captured on my computer/in vegas? i think the canon files i have were acquired from a firestore or captured in premiere pro 2. this problem occurs on both of my machines

my system specs are

#1
xp/sp2
vegas 7c
core 2 duo e6300
1gb ddr2

#2
xp/sp2
vegas 7c
p4 3.2e ghz
2gb ddr
 
You have to pre-render the clips to play smoothly. Or do a ram preview for a few seconds (length depends on available ram) to see how a transition or FX works. As you say when you convert M2t to a WMV it palys like butter. If you have Cineform Connect HD you can batch render clips into the Cineform Intermediate AVI and the clips will play smooth unless you add FX or transitions which must be rendered for real time play back.

S Cannon
 
actually it's the opposite - i downloaded some hd wmv files and converted those to hdv files and they play perfectly fine without any kind of ram preview. also, this is all only concerning playback with no fx or transitions applied, i should have originally noted that - my apologies. thank you though for you quick response.
 
scannon said:
You have to pre-render the clips to play smoothly. Or do a ram preview for a few seconds (length depends on available ram) to see how a transition or FX works. As you say when you convert M2t to a WMV it palys like butter. If you have Cineform Connect HD you can batch render clips into the Cineform Intermediate AVI and the clips will play smooth unless you add FX or transitions which must be rendered for real time play back.

S Cannon
Click to expand...


I thought it might be vegas 7.0c that has problems dealing with M2t files but now it seams you will have to use connect hd codec rather than the one built into vegas. but i will try the wmv to hdv method to see if that works for me...but too bad the m2t files are choppy vs regular dv files that are flawless. Maybe vegas will update it with a better codec to get around this problem.
 
Since your downloaded HDV clips are n 24f, I'm pretty sure they've still got the pull-down added to store them in a 60i .mtv file. I don't think Vegas will do the pull-down removal in real-time for displaying on a true 24p timeline.

The best way to see that is to look at the frame rate shown in the preview window (look at the very last number on the bottom line) - on your timeline it should show 23.976 fps if it's keeping up. If not, then it just can't convert on-the-fly.

Also, I believe 24f footage uses 'advanced' pull down, which is good for conversion, but will look oddly syncopated when simply played back. Make sure it's not just this syncopation that you're dealing with.

Using Cineform's HD-Connect has the two advantages that it will properly remove the 24f's pull-down, resulting in a true 24p file for dropping on a 24p timeline, plus the Cineform format file will be easier on your CPU during playback.

However, don't rush out to buy Connect-HD just because of this. Version 7c improved the HDV speeds such that the speed advantage of cineform isn't so huge, and you *should* be able to get HDV playback on a decent machine.

Hope it helps,

Dip
 
Well I just played with the demo version with connect HD on my 3800 x2 machine and found that after comparing raw m2t into my timeline vs using the connect HD conversion avi..The converted avi works much better in realtime...and you can scrub across the timeline similar to using regular dv footage. In addition it seems having that codec in the machine tends to work better than relying on the vegas cineform codec.
 
i was under the impression that canon 24f hdv was recorded to tape with no pull down - just straight 23.976. also, when i play the downloaded m2t in question with media player and check the properties, the frame rate is displayed as 23.976, whereas when i check a 24p dv file with 2-3 pull down, it lists 29.97. so i'm quite sure that the pull down is not the issue.

are all mpeg codecs created equal? i mean, if this file was captured in premiere using a different mpeg codec, would that hinder its use in vegas, since vegas uses a different codec? or is that just silly? with the hdv m2ts that i render directly out of vegas, i can scrub, play and even add fx with only a slight framerate hit; but with these clips that i downloaded, i can barely play it back without it getting choppy.
 
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