Dragging Video Clips in Less Than 1 Frame?

stevefoobar wrote on 9/1/2007, 9:42 AM

I have been usng Vegas for about a year and Pinnacle Studio for about 4 years. I'm currently having a raging battle on the Pinnacle forums about a feature in Vegas I was suggesting Pinnacle implement. Namely, the "supposed" ability to unlock the single frame snap feature (Options, Quantize to Frames unchecked) so you can "supposedly" drag video clips in less than 1 frame increments.

All of the Pinnacle guys are telling me that his is impossible because you can't edit video in less than 1 frame increments (audio is a different matter of course). They say that there are only 30 frames of video per second, so the lowest editing resolution you can possibly have in an editor for video is 1 frame or 1/30th of a second (assuming normal NTSC standards).

They further claim that Vegas is just making it "appear" to allow this to happen so you can drag the attached audio track to the video track in less than 1 frame increments, but in reality (and here is where it gets really interesting) Vegas is NOT doing this, but instead will still only output the dragged video on the nearest single video frame boundary when you render.

They also claim you can test this by putting two identical test clips of video on tracks in Vegas, setting each one to 50% transparency so you can preview them both, then unchecking Options, Quantize to Frames. Next zoom in extremely and drag one of the video clips in less than 1 frame increments and they claim you will NOT see any ghosting or shifting in the preview window (or rendered video) until you actually shift one of the video clips a whole frame.

I have tried this and can't determine if this is true or not because I don't have good test video clips with clearly defined moving lines, so when I do this test I can't really determine if the video is REALLY shifting or not because it may be very subtle until you shift by at least 1 frame.

Then again, the Pinnacle forum guys might be right and this isn't really a capability in Vegas, but a sort of misleading feature.

Does anyone know for sure, how this is done in Vegas or whether this is really possible or is Vegas just making it look possible so you can drag the audio clips in less than 1 frame increments?

Further, if this is a real feature, how is this being accomplished? The Pinnacle forum guys are claiming that even if Vegas is doing this, the resulting video will look horible because they would have to re-render and interprolate each of the video frames from the point of the drag onwards.

Please help, especially if there are any Sony Vegas programmers/designers out here monitoring.

Thanks a lot and I'm VERY sorry for the long post, but it's a bit of a complex topic.

Comments

Chienworks wrote on 9/1/2007, 11:11 AM

Quick answer, the Pinnacle guys are right.

Vegas will let you position the video event on the track so that it isn't lined up to frame boundaries, but the default action will be for the event frames to be adjusted to the project frames (which is what you want). If you force resample then Vegas will grab a proportional amount of two adjacent source frames that overlap the project frame borders and mix them together (which you problably don't want).

What do you expect to achieve by shifting the video in sub-frame amounts? Can you think of any good result that would come from this? How could this possibly be better than having the frames aligned?

stevefoobar wrote on 9/1/2007, 12:00 PM

Thanks. Yours is the first reply.

Good question on your part. The only reason I was trying to use this feature in the first place was to sync two different video takes of the same scene from two different amateur cameras that were NOT synced in any way. Of course, in Vegas I can sync the audio tracks to very fine resolution, so I was hoping the programming magicians at Sony (Sonic Foundry) had figured out a way to do this without the degradation problems.

It looks like they did NOT, so now I'm wondering why they even allow you to drag ANY video clip after you uncheck quantization and make it appear as though it is working. I understand unlocking quantization for audio tracks, but why even allow this to supposedly occur on video tracks?

ADB wrote on 9/1/2007, 2:06 PM

I'm curious as to why you are using both Pinnacle and VMS and how they compare. I'd been using Studio 8 before changing to VMS ... mainly because I became nervous about the reported number of Pinnacle bugs and instability in later versions.

Chienworks wrote on 9/1/2007, 2:24 PM

I think the better question is, why not allow it? What if the frame rates don't match? Then maybe you have good reason to move the video track in sub-frame increments. Also consider that originally Vegas was an audio-only editor so moving clips by frames was a concept that didn't exist. Quantizing to frames is a recent addition to Vegas and i assume the programmers wanted to allow users to still use the non-quantized behavior that they were used to if they wanted it.

However, keeping in mind that in most circumstances you describe, the frame rate of the two cameras is going to be the same, and match the project frame rate. Since frames are discrete slices of time, there's no way to adjust differences in video sync by partial frame increments; the visual information between frames simply doesn't exist. That's ok though because in almost all circumstances getting the video synced to the closest frame is close enough and your audience will never notice. If the audio is off by a partial frame then by all means move the audio as necessary to sync it to the other track. Leave the video where it is. No one will notice if the audio and video are off by less than half a frame.

Actually, for that matter, the audio and video really only match up at most for one sample each frame. For the entire other 1,601 samples during each frame they're not synced. Have you ever noticed this when watching video? No? I didn't think so. Moving the audio left or right up to a half a frame just means that a different sample out of the 1602 each frame will be in sync, but that one sample will still fall within the correct frame. So don't sweat it if you have to move the audio a few microseconds without being able to move the video too.

stevefoobar wrote on 9/1/2007, 4:12 PM

Actually, ADB, I have both because I have found that Pinnacle Studio is a much easier program to use for some things because I often don't edit video for months then have to re-learn some things in Vegas, whereas I never have to do this in Studio because it is VERY straight-forward.

Also, I have many more effects in Pinnacle Studio than I have with Sony Vegas, so that's another reason.

Vegas is a far more sophisticated program than Studio however and can be used to mix more complex audio whereas Studio simply can't in my opinion.

stevefoobar wrote on 9/1/2007, 4:14 PM

Thanks Chienworks. You have helped me put to bed a long, long thread in the Pinnacle forum, so I'll have to go back there and admit that I was wrong. Personally, I think it's misleading for Vegas to even allow one to drag video clips in less than 1 frame increments and I may suggest this to the developers.

Thanks again for the input and help.

Steve

Chienworks wrote on 9/1/2007, 7:03 PM

Well, as i pointed out, there are valid reasons to allow it. And when there isn't any reason to you can turn on quantize to frames to prevent it.

stevefoobar wrote on 9/2/2007, 8:10 AM

OK, then I guess I don't fully understant the valid reason for this feature and how it will help sync two vid clips that are different frame rates, say 24fps and 30 fps. I'll probably have to experiement myself to actually see how this feature can help.

Thanks again. chienworks. I'm not an expert in video editing like I am in audio editing/mixing, so I don't have all the video concepts down yet. :-)

ADB wrote on 9/2/2007, 2:38 PM

Thanks Steve ... I agree with you on the simplicity of Pinnacle, or Ulead for that matter. VMS does take a little longer to learn but once you do, there's no looking back.

stevefoobar wrote on 9/6/2007, 10:20 PM

Thanks for the comment ADB. I guess I'm not at that point yet with Vegas, but hopefully will be eventually. It's clearly more powerful but I keep going back to Pinnacle for "simple" projects, especially those that don't involve audio editing.