Lip Sync Problem

mjroddy wrote on 8/30/2005, 3:58 PM
After a search in the Forum's history, it appears I'm the only one having this problem. I'm editing in m2t files because I'm not doing a lot of transitions or compositing and my computer can ram render what I need to see readily enough.
My problem is that I'm loosing sync on most of my clips during a :30 spot - 3 of them actually. I have 3 spots with on-camera talent and none of them are holding sync consistantly.
Is it because I'm using the raw m2t files? I've tried the project as DV (i'm using widescreen on all 3) as well as 1920x1080 60i. I done ram renders and (shift M) renders and even rendered out to WVM and had the same results.
Is there a sync issue I am not finding in the forum history that I should research?

Comments

mjroddy wrote on 8/31/2005, 9:13 AM
Just me then? Or is the answer so obvious it's not worth talking about.
Anyone?
p@mast3rs wrote on 8/31/2005, 10:28 AM
Dude, I think it is because you are using the raw .M2T files. Have you tried converting to cineform avi and played that back? That should give you a better idea if you are just having playback perfoemance issues or if you have a problem with your synch in your source footage.
Spot|DSE wrote on 8/31/2005, 10:29 AM
Matthew, as Patrick suggests, it might be the way your decoder is buffering the audio from the HDV file. Creating an intraframe file vs using the inter-frame file, will likely make all the difference.
mjroddy wrote on 8/31/2005, 10:35 AM
Patrick, I was hoping to avoid that step, but it looks like it can't be avoided. Thanks for the tip.
DSE - I have no idea what you just said (about inter vs intra), but I'll take your word for it and convert.
Thanks guys!!!
Spot|DSE wrote on 8/31/2005, 10:56 AM
intraframe=All frames contain all information
interframe=one frame contains information, other frames contain non-redundant information about the frame.
(I frame is like a picture, all information is there. In 1080 mpeg, you have 2 I-frames per second, the other 27 frames are frames that predict what's going to happen next, and looks backwards and forwards, if I can simplify it that much)

DV is intraframe, HDV is interframe. Interframe is kinda like having a couple "reference" frames, with a bunch of "guessing" frames that refer to the couple of reference frames. The "guessing frames" save a lot of storage space, because they only store what's changed in the frame, not every pixel in the frame.
Converting to either proxy or Cineform should give you a more stable read/playback.
mjroddy wrote on 9/19/2005, 11:41 AM
First, thanks for the explanation.
I thought I'd have the problem licked by encoding straingt from Connect HD.
However, (I hate those "howevers"), I just did a new project with a spokesperson on camera, digitized with Connect HD and using those AVIs on the timeline.
My audio is delayed by 3-4 frames on every clip. It's simple enough to Ungroup the clip and shift the audio forward by 3-4 frames, but why is this likely to be happening?
I have fast drives, 2.5 gig of RAM and am running on Nvidia GeForce 6600 with updated drivers. All under Window$ XP Pro and 3.00GHz (Vegas 6, of course).
So I've tried;
M2Ts - same result
M2Ts converted to YUV using Gearshift - same result
M2ts converted to Intermediary AVI - same result
AVI encoded using Connect HD - same result
Anything else I should be doing differently?