DV vs. HD editing, sync issues? at DVinfo.net

Ted Bragg · September 19th, 2004, 10:35 AM

I've done a small amount of DV editing, and was baffled by the methods used to keep a/v sync'd.

Unlocked audio is pretty much standard on low-end cams, and makes for a massive headache when editing. DVD authoring from cheap-cam DV is a nightmare.

Do HD cams have this problem? Are they using the same methods to keep audio in sync, or are they using something else? I'm not talking about the HDVs, but the big mama-jamma HDs like CineAlta, Panavision, etc...

I've heard some guys report they can shoot and get great sound straight to HD tape, it stays in sync and they don't run into the crazy problems I've had with DV.

Anybody?

Bill Pryor · September 19th, 2004, 10:45 AM

I've never had a sync problem with any DV or DVCAM camera I've used. I suppose with a DV camera that has unlocked audio, if you shot something like an hour long speech, the sync technically could drift. Most everything I've done is with professional DVCAM cameras, but I've also edited stuff from XL1s and haven't had any sync problems.

Ted Bragg · September 19th, 2004, 10:49 AM

Strange. It must be the NLE I used, then (Pinnacle).

Audio would do fine for the first few cuts, but then it'd get out of sync after the edit points. It wasn't too noticable in the editor, but when put on DVD, it was awful.

I'd like to go with HD, but I don't want to spend a bunch of money renting one if the audio sync issues are the same.

Which NLE is recc'd for HD? FCP is great, but I"m stuck with a PC workflow.

Bill Pryor · September 19th, 2004, 10:54 AM

It must be. Or maybe when you're editing you're not keeping your tracks in sync. It's easy to slip something out of sync when editing. Also it's easy to put it back with most systems. I don't know anything about Pinnacle. With Avid you can lock the tracks so you can't screw up if you're not paying attention, if you want. And, if you slip an audio track a frame out of sync, it tells you with little white number that indicates the number of frames you're out of sync.

George Ellis · September 19th, 2004, 02:55 PM

Are you using Edition? If you are using lots of cuts in the Yellow mode, the audio cuts can slip unnoticed to the left. Especially if you have disbanded clips.

Ron Evans · September 20th, 2004, 02:26 PM

The DV spec for unlocked audio will result in a slip of less than 1/3 a frame!!!!!. Not good enough for linear editing but of no consequence for NLE. The sync slip you are encountering is due to your capturing software, editing software, MPEG encoder or authoring software. SOme problems you may encounter:- setting up capture for 48khz audio but actually using a tape with 12bit 32khz audio. importing 44.1 khz( CD ) audio in a project set for 32khz......etc. UNless you resample the audio there will be a sync difference in the final production. Essentially audio samples will be counted to line up the video and if you have the wrong sample rate they will go out of sync. I use DVRaptorRT2, Sony camcorders recording at LP ( 32khz ), edit with Premiere 6.5 and output to DHR1000. Most of what I do are theatre shows lasting over 2 hours. I still have perfect lip sync right to the end. However, Premiere knows I capture audio at 32khz but output settings are 48khz and Premiere resamples for me staying in sync. I also output to a Panasonic E30 DVD recorder then author using DVDlab, create audio and video TS folders and burn with Nero everything still in sync.

Ron Evans

Ted Bragg · September 23rd, 2004, 06:19 PM

Wow, that right there just saved me weekss of searching on this.

Turns out HD setups can be configured to record locked audio straight to tape. No sync issues.

Your tips for shoot/capture & burn are just what I needed. I have all of those apps at my disposal. Thanks a bunch!

September 19th, 2004, 10:35 AM	#1
Ted Bragg Regular Crew Join Date: Jun 2003 Location: Houston, TX Posts: 105	DV vs. HD editing, sync issues? I've done a small amount of DV editing, and was baffled by the methods used to keep a/v sync'd. Unlocked audio is pretty much standard on low-end cams, and makes for a massive headache when editing. DVD authoring from cheap-cam DV is a nightmare. Do HD cams have this problem? Are they using the same methods to keep audio in sync, or are they using something else? I'm not talking about the HDVs, but the big mama-jamma HDs like CineAlta, Panavision, etc... I've heard some guys report they can shoot and get great sound straight to HD tape, it stays in sync and they don't run into the crazy problems I've had with DV. Anybody?

September 19th, 2004, 10:45 AM	#2
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	I've never had a sync problem with any DV or DVCAM camera I've used. I suppose with a DV camera that has unlocked audio, if you shot something like an hour long speech, the sync technically could drift. Most everything I've done is with professional DVCAM cameras, but I've also edited stuff from XL1s and haven't had any sync problems.

September 19th, 2004, 10:49 AM	#3
Ted Bragg Regular Crew Join Date: Jun 2003 Location: Houston, TX Posts: 105	Strange. It must be the NLE I used, then (Pinnacle). Audio would do fine for the first few cuts, but then it'd get out of sync after the edit points. It wasn't too noticable in the editor, but when put on DVD, it was awful. I'd like to go with HD, but I don't want to spend a bunch of money renting one if the audio sync issues are the same. Which NLE is recc'd for HD? FCP is great, but I"m stuck with a PC workflow.

September 19th, 2004, 10:54 AM	#4
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	It must be. Or maybe when you're editing you're not keeping your tracks in sync. It's easy to slip something out of sync when editing. Also it's easy to put it back with most systems. I don't know anything about Pinnacle. With Avid you can lock the tracks so you can't screw up if you're not paying attention, if you want. And, if you slip an audio track a frame out of sync, it tells you with little white number that indicates the number of frames you're out of sync.

September 19th, 2004, 02:55 PM	#5
George Ellis Trustee Join Date: Feb 2004 Location: Suwanee, GA Posts: 1,241	Are you using Edition? If you are using lots of cuts in the Yellow mode, the audio cuts can slip unnoticed to the left. Especially if you have disbanded clips.

September 20th, 2004, 02:26 PM	#6
Ron Evans Inner Circle Join Date: Mar 2003 Location: Ottawa, Ontario, Canada Posts: 4,220	The DV spec for unlocked audio will result in a slip of less than 1/3 a frame!!!!!. Not good enough for linear editing but of no consequence for NLE. The sync slip you are encountering is due to your capturing software, editing software, MPEG encoder or authoring software. SOme problems you may encounter:- setting up capture for 48khz audio but actually using a tape with 12bit 32khz audio. importing 44.1 khz( CD ) audio in a project set for 32khz......etc. UNless you resample the audio there will be a sync difference in the final production. Essentially audio samples will be counted to line up the video and if you have the wrong sample rate they will go out of sync. I use DVRaptorRT2, Sony camcorders recording at LP ( 32khz ), edit with Premiere 6.5 and output to DHR1000. Most of what I do are theatre shows lasting over 2 hours. I still have perfect lip sync right to the end. However, Premiere knows I capture audio at 32khz but output settings are 48khz and Premiere resamples for me staying in sync. I also output to a Panasonic E30 DVD recorder then author using DVDlab, create audio and video TS folders and burn with Nero everything still in sync. Ron Evans

September 23rd, 2004, 06:19 PM	#7
Ted Bragg Regular Crew Join Date: Jun 2003 Location: Houston, TX Posts: 105	Wow, that right there just saved me weekss of searching on this. Turns out HD setups can be configured to record locked audio straight to tape. No sync issues. Your tips for shoot/capture & burn are just what I needed. I have all of those apps at my disposal. Thanks a bunch!