Extremely choppy/slow video preview with reversed clips

Justinec101

Justinec101

Active member
I use the reverse function constantly and have just started using an hmc150. I shot in 720 30p (although it's saying it's 60p. . . that's a problem for another day) and reverse playback is terrible. I can preview 720p footage at Preview Full with basically no lag whatsoever, but as soon as I try to preview a reversed clip it's unwatchable, even at Draft/quarter. Trying to do a dynamic ram preview on the reversed clip is like watching a snail run the quarter mile.

*Edit. . . Ok I understand the 30p-60p thing now, but I just did a test to see if this reverse clip issue is effecting actual rendering. . . well one minute of a reversed clip is taking 10-15 minutes to render versus 1 minute for a regular clip. This is a huge problem since my projects usually run about 5 minutes and can contain as much as 50% reversed material.

*Edit, more info. . . Usually when rendering, my CPU usage is at around 95%. When rendering reversed clips it's hovering around 15-25%. What is the deal here?!?!
 
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The deal is the same as every other story about dropping AVCHD on a timeline in practically any editor. It doesn't belong there, and it's going to bite you in the but one way or another. Transcode to an actual editing format, and your problems will disappear.

(your computer is KILLING itself trying to do the tricky math of figuring out long-GOP in reverse and it's taking forever to do so because long-GOP footage is set to decode in one direction only.)
 
Thanks for replying. Is there a good format to convert to? I tried the Neoscene demo, but the files were so big I don't think it's going to be an option for me, not to mention the way it handled my 30p footage from the HMC (it thinks it's 60 and speeds it up 2x, while leaving the audio the original length). I could just film in 60p but I'm still left with the huge file sizes.

I looked into proxy editing but it seems like a hassle and I'm still left with long render times in the end.

The great benefit to vegas and the hmc150 was that I could just drop avchd straight into my timeline without a lot of hassle, and that has been 99% true until I ran into this.

For the hell of it I took a clip and split it about 30 times into separate frames, rearranged them in reverse order and grouped them. . . and bam!(a very slow bam!) full speed reverse play =P Of course I've no intention of doing this on a regular basis. . .but it'd be nice if there was some sort of effect or script that could duplicate this process.
 
I think you have pretty much answered your own question.

* Transcoding to an editing codec (like Neoscene or Lagarith) equals huge files and an extra step.

* Proxy editing requires extra steps.

If you want hassle free editing with AVCHD you could do the following. Upgrade your computer to the fastest 6 core + 8 gigs of ram + Solid state hard drive and the newest version of Vegas 10 (it's faster then 9). I'm pretty sure that will play AVCHD reversed clips in real time no probelm. In fact when I get home I'll try it on my system and see.
 
Justine, I am sorry to say that Neoscene does not create huge file sizes. Not by the standards of HD. Neoscene creates dome of the smallest file sizes of any proper editing codec out there. What you seem to be used to are the incredibly compressed files that are recorded by today's cameras. It's the fact they are so compressed that makes them both slow to edit, and unsuitable for editing...and not just because they are slow.

Buy yourself some disk space. It's cheap. And transcode your files to a better format. Or you can upgrade your machine and your version of Vegas. Or you can just suffer through what you're doing now.

The choice is yours.

Best of luck.
 
I'll stick with what I'm doing for now. I edited my first full project with AVCHD footage and it went pretty smoothly. I used reversing sparingly but even in the spots where I used it I could at least get an idea of what my end result would look like. And just using reverse playback instead of actually reversing the clip allows me to see it in reverse at full speed.

Neoscene also messes up anything shot in 30p, apparently since it's a non-native format for the hmc, so I end up with a sped up clip and full length sound.

For now the benefits of editing AVCHD outweigh the negatives.
 
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