poor MPEG-2 playback in timeline

weasel_ferret wrote on 1/8/2005, 6:48 PM
Hi. Can someone enlighten me as to why Vegas cannot satisfactorily play back MPEG-2 footage in the timeline? Although neither Windows Media Player nor The Core Media Player have a problem playing back an NTSC MPEG-2 video/audio stream at full frame size and rate, Vegas plays back the same footage at 2 frames per second-- if I'm lucky.

I have my project settings set correctly for NTSC 720x480, 29.97, blah blah blah.

Please don't tell me to convert the MPEG-2 footage to DV. I'm not willing to do that, since I'm going to end up rendering to MPEG-2 in the end anyway, and it's ridiculous to step on the quality by transcoding between codecs like that.

I've also attempted using the "prerendered files" preview option, thinking that Vegas would be happier if I used DV preview footage instead. Unfortunately, for practical purposes, this feature is completely useless. Every time I make any edit, the preview files are deleted from the timeline. What is up with that? I am truly shocked that Vegas requires re-rendering preview files every time one makes a cut.

If the answer is, "This is an feature, not a bug," then I respectfully request that realtime playback be supported for codecs other than DV. Vegas has the most intuitive interface of any video editor I've ever used, and I have used many. It is truly sad that at VERSION FIVE there are still such severe limitations in basic functionality. MPEG-2 is a universal format, and it should be fully supported.

Comments

BillyBoy wrote on 1/8/2005, 8:13 PM
Need more details... WHEN doesn't Vegas playback MPEG footage? If all the time that's one issue, if only after applying FX filters that's something else. If it slows to a crawl only when in certain preview modes, that's still a different issue. The first is likely more to do with a particular file, the second is related to how you have your system set up, how powerful it is, what, how many filters you've applied, if or not you changed frame size, frame rate, format, etc.. The third is easy to spot, change preview mode to preview or draft and if the problem goes away or improves either you got tons of filters/effects you've applied or your system is under powered or isn't set up just right.

TheHappyFriar wrote on 1/8/2005, 8:34 PM
you do realize that editing the mpeg file in Vegas will NOT help keep the current quality, right? Most likely it will degrade the quality more because it's re-compressing already compresed video. Converting your video to DV footage (TMPGenc would be the easiest) would probley have no ill effect on the quality at all & would speed up the editing & final rendering.

And you've probley got an older system. On an AMD XP 2500 with 512mb ram & a dedicated video HD mpeg-2's play back at 29.97fps, just like their susposed to. You DID capture all I-frames, didn't you? If not that's not a good thing.

farss wrote on 1/8/2005, 8:43 PM
Withour getting too technical mpeg-2 is a difficult call for a NLE. Depending on the GOP structure lots of data needs to be read to create the current frame. Now that isn't so much an issue when all the software has to cope with is playing the stream. But when you build a system sepcifically where the user needs to jump anywhere on the timeline things get a bit tricky and very CPU and RAM intensive. Try stepping through a mpeg-2 file one frame at a time backwards and forwards in any player and you'll see what I mean.
Yes mpeg-2 is used a lot, some high end recording systems use it but as far as I know they use a very short GOP which makes editing that much easier.
If you want to edit mpeg-2 I'd suggest there are probably better systems than Vegas, I've tried some and they were painful, I certain the higher end stuff is better but I suspect you need pretty beefy hardware and they probably have lots of restriction on the variants of mpeg-2 that they handle.
Bob.
weasel_ferret wrote on 1/9/2005, 1:32 AM
Of course I know that lots of filters will slow everything down, and that Vegas will recompress at render time. I'm just talking about playback in the application.

This is not a super fast system (1GHz, 1GB RAM) but it should be fine for simple MPEG-2 playback. And it is fine in player applications, just not in Vegas.

I do not see why NLE performance should be any different than dedicated player app performance, if all I'm doing is playing forward at 1:1 speeds. Yeah, I can imagine that skipping around might be harsh, but one would think that optimizing Vegas for realtime, no-frills MPEG playback would not be that big of a deal. It's simply a matter of whether the corporation considers that feature a worthwhile expenditure of developer time-- and clearly, MPEG playback is not a priority.

I am giving up on Vegas and am going to try some Mom-and-Pop consumer MPEG editors.
weasel_ferret wrote on 1/9/2005, 1:33 AM
Oh, and no one addressed my complaint about the preview files. It's simply shameful that the feature is practically useless.
TheHappyFriar wrote on 1/9/2005, 6:42 AM
I never use the preview files (I always render to a new track). TMPGenc is an mpeg-1/2 editor that would allow you to cut/split the mpeg files all oyu want.

I don't think most NLE's do mpeg-2 well. It's not a Vegas thing (Premiere 6 & before wouldn't even put them on the timeline)
Spot|DSE wrote on 1/9/2005, 9:55 AM
MPEG is a HUGE hit on the processor. That's aside from the fact that the engineers at Sony aren't interested in spending the dev time for editing in a problematic format anyway. MPEG simply isn't an editing format. Not in long GOP. Was never intended to be. So, couple the hard hit on the processor with the lack of optimization on the side of the software, you've got a bad experience.
Ulead's Media Studio Pro does a good job of cutting/editing MPEG and uses smart recompression, so it might be fewer features, but it will likely do what you want. The interface is klutzy....but if it does the job, who cares?