audio sync on recorded footage off? at DVinfo.net

Marty Hudzik · January 15th, 2008, 08:45 AM

I am putting together a short narrative and have found that the audio track leads the video by 3 frames. I am shooting HDV 24f and capturing into Premiere Pro. It is quite obvious that the audio is slightly out of sync and through experimentation I was able to determine the 3 frame difference. I have found a workaround for the moment but was wondering if this is normal for the H1......I have been using it for almost 2 years but just witnessed this for the first time.

Thanks all.

Marty Hudzik · January 21st, 2008, 03:48 PM

Not a single reply? I can't believe nobody has seen this issue . I remember the audio on the DVX1000 used to be slightly off.....was wondering if this was the case here too in 24f because of processing.

so once again.....anyone seeing this phenomenon?

Chris Soucy · January 21st, 2008, 04:38 PM

I have heard of this phenomina on JVC cameras (from memory) where the audio wasn't locked to the video on certain machines/ tape types, but nothing about the H1.

This leads me to wonder if the sync issue is present when the tape is played straight from the camera to a big screen, or only after you have ingested/ played with it, and thus is a PP issue?

CS

Bill Pryor · January 22nd, 2008, 04:57 PM

I've never heard of the problem. When you play back the tape in the camera, not hooked up to a computer, is it in or out of sync? If it's in, then it's not the camera. If it's out...time for a service call.

Marty Hudzik · January 22nd, 2008, 07:03 PM

I will try to check it out tonight. I have never noticed it until now and the only thing different here is I was using a boom pole with a very high end mic out there. This was of course plugged into the xlr inputs on the back of the camera. I don't know if that could have any effect but that is the only thing that is different about this session.

Carlos Quinones · January 22nd, 2008, 09:10 PM

Marty....

That the problem....actually not a problem is normal to have 2 or 3 frams delay in the audio when you are using a boom. That's because audio travels slower that light...so you will see the images first and then the audio comes right behind....

Is not a big difference but you could just slide the track and put it together as you like.

I own an H1 and it happends to me all the time specially when we are making movies or music videos...there's when the clap board comes in handy to synch the audio with the image.

But don't be surprise, this would happend with any camera and any settings, and some times people don't notice this detail.

Take Care !

Carlos Quinones
It's Written Productions, LLC.

www.myspace.com/itswrittenproductions
www.carlos-quinones.com

Pete Bauer · January 22nd, 2008, 10:19 PM

If the audio is leading the video on the playback, it isn't due to sound propagation differences; if the mic is a long way from the sound source, then it can LAG the video. Sound at sea level travels about 1128 feet/sec (344 m/s). So for 30fps video, each 36.7 feet of distance the mic is from the sound source, there will be a frame of audio lag. It's about 44 feet in 25fps PAL country.

Don't know what's causing your problem. One possibility is latency either due to the overall system getting bogged down (basically not enough horsepower), or sometimes even in a fast system the audio subsystem just plain has latency...but again, those issues usually mean the audio lags, not leads. Are you editing in native mpeg (m2t)? If so, perhaps the latency is with decompressing the video?

People have also posted about suspecting that dropped frames cause a loss of synch. Will be curious if you can perceive the audio lead when viewing directly from tape.

BTW, I don't think it is an issue for playback, but when recording you can choose in the menus whether you want the audio monitoring during shooting to be in real time ("normal") or to be delayed slightly to stay in synch with the viewfinder video ("line out.") With "normal" you'll hear the audio in your headphones will slightly lead the viewfinder video during shooting as Carlos mentioned. Either way the recording is supposed to be in synch. See p67 of the manual in the US English version.

Marty Hudzik · January 23rd, 2008, 09:49 PM

The audio was definitely leading here. I was editing in native 24f mpg files in Premiere. My system is a quad-core with 4gb ram and very fast drives so on paper it has the horsepower.....but as you said....latency happens. I have a sound blaster audigy card also....maybe that is the culprit. I have since exported the project as a blu-ray compliant file and played it on my Ps3 in HD and it looks flawless. The audio does not appear to be lagging now (which would be the result of timeshifting it to compensate for latency on the PC).

I am travelling the next 8 days so I will not get to test the direct footage. I should point out that the original audio was "very" close. It was hard to perceive that it was off. However, when moving it 3 frames it looked perfect.

Thanks all.

Marty Hudzik · February 15th, 2008, 08:31 AM

Just a minor update. When it was all said and done, and I authored a DVD of the final content and viewed it on a set-top DVD player the audio seemed to be off again....in the other direction. Apparently there is some latency or something involved on my system that causes the video to lag behind the audio slightly. When I moved the audio 3 frames down the timeline it matched the playback in Premiere perfectly. However, the final DVD render had the audio lagging a little now.

I guess Premiere is just not efficient at previewing audio and HD video at the same time and keeping everything in sync on the timeline. This is a pretty robust system too...4GB Ram, Quad-Core PRocessor and fast drives. My sound card (SB Audigy 2) is probably the oldest component. Anyone know of a good modern card to replace it?

Thanks.

Floris van Eck · February 15th, 2008, 09:50 AM

Sounds like a typical Premiere problem. Really, I had so many issues with Premiere that I jumped ship to Final Cut Pro. Which I do not regret as I have had no issues and no crashes with Final Cut under Leopard. In the six months before I spend too much of my time on problem solving. It might have been my computer, it might have been Premiere... but it didn't work.

Steve Tedesco · February 15th, 2008, 01:22 PM

Had a out of snyc problem with my xl2 and FCP, had camarea set at rec-run and FCP set to make new clip at time code break. had old footage on tape, there was a break in the time code then after that it was out of sync. went back and captured again without making new clips and it was fine

January 15th, 2008, 08:45 AM	#1
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	audio sync on recorded footage off? I am putting together a short narrative and have found that the audio track leads the video by 3 frames. I am shooting HDV 24f and capturing into Premiere Pro. It is quite obvious that the audio is slightly out of sync and through experimentation I was able to determine the 3 frame difference. I have found a workaround for the moment but was wondering if this is normal for the H1......I have been using it for almost 2 years but just witnessed this for the first time. Thanks all.

January 21st, 2008, 04:38 PM	#3
Chris Soucy Inner Circle Join Date: Feb 2007 Location: Fairfield, Dunedin, New Zealand Posts: 3,691 Images: 18	Hi Marty........... I have heard of this phenomina on JVC cameras (from memory) where the audio wasn't locked to the video on certain machines/ tape types, but nothing about the H1. This leads me to wonder if the sync issue is present when the tape is played straight from the camera to a big screen, or only after you have ingested/ played with it, and thus is a PP issue? CS

January 22nd, 2008, 10:19 PM	#7
Pete Bauer Wrangler Join Date: May 2003 Location: Eagle River, AK Posts: 4,100	If the audio is leading the video on the playback, it isn't due to sound propagation differences; if the mic is a long way from the sound source, then it can LAG the video. Sound at sea level travels about 1128 feet/sec (344 m/s). So for 30fps video, each 36.7 feet of distance the mic is from the sound source, there will be a frame of audio lag. It's about 44 feet in 25fps PAL country. Don't know what's causing your problem. One possibility is latency either due to the overall system getting bogged down (basically not enough horsepower), or sometimes even in a fast system the audio subsystem just plain has latency...but again, those issues usually mean the audio lags, not leads. Are you editing in native mpeg (m2t)? If so, perhaps the latency is with decompressing the video? People have also posted about suspecting that dropped frames cause a loss of synch. Will be curious if you can perceive the audio lead when viewing directly from tape. BTW, I don't think it is an issue for playback, but when recording you can choose in the menus whether you want the audio monitoring during shooting to be in real time ("normal") or to be delayed slightly to stay in synch with the viewfinder video ("line out.") With "normal" you'll hear the audio in your headphones will slightly lead the viewfinder video during shooting as Carlos mentioned. Either way the recording is supposed to be in synch. See p67 of the manual in the US English version. __________________ Pete Bauer The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. Albert Einstein Trying to solve a DV mystery? You may find the answer behind the SEARCH function ... or be able to join a discussion already in progress!

January 21st, 2008, 03:48 PM	#2
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	Not a single reply? I can't believe nobody has seen this issue . I remember the audio on the DVX1000 used to be slightly off.....was wondering if this was the case here too in 24f because of processing. so once again.....anyone seeing this phenomenon?

January 22nd, 2008, 04:57 PM	#4
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	I've never heard of the problem. When you play back the tape in the camera, not hooked up to a computer, is it in or out of sync? If it's in, then it's not the camera. If it's out...time for a service call.

January 22nd, 2008, 07:03 PM	#5
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	I will try to check it out tonight. I have never noticed it until now and the only thing different here is I was using a boom pole with a very high end mic out there. This was of course plugged into the xlr inputs on the back of the camera. I don't know if that could have any effect but that is the only thing that is different about this session.

January 22nd, 2008, 09:10 PM	#6
Carlos Quinones Regular Crew Join Date: Sep 2006 Location: Miami Florida Posts: 70	Marty.... That the problem....actually not a problem is normal to have 2 or 3 frams delay in the audio when you are using a boom. That's because audio travels slower that light...so you will see the images first and then the audio comes right behind.... Is not a big difference but you could just slide the track and put it together as you like. I own an H1 and it happends to me all the time specially when we are making movies or music videos...there's when the clap board comes in handy to synch the audio with the image. But don't be surprise, this would happend with any camera and any settings, and some times people don't notice this detail. Take Care ! Carlos Quinones It's Written Productions, LLC. www.myspace.com/itswrittenproductions www.carlos-quinones.com

January 23rd, 2008, 09:49 PM	#8
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	The audio was definitely leading here. I was editing in native 24f mpg files in Premiere. My system is a quad-core with 4gb ram and very fast drives so on paper it has the horsepower.....but as you said....latency happens. I have a sound blaster audigy card also....maybe that is the culprit. I have since exported the project as a blu-ray compliant file and played it on my Ps3 in HD and it looks flawless. The audio does not appear to be lagging now (which would be the result of timeshifting it to compensate for latency on the PC). I am travelling the next 8 days so I will not get to test the direct footage. I should point out that the original audio was "very" close. It was hard to perceive that it was off. However, when moving it 3 frames it looked perfect. Thanks all.

February 15th, 2008, 08:31 AM	#9
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	Just a minor update. When it was all said and done, and I authored a DVD of the final content and viewed it on a set-top DVD player the audio seemed to be off again....in the other direction. Apparently there is some latency or something involved on my system that causes the video to lag behind the audio slightly. When I moved the audio 3 frames down the timeline it matched the playback in Premiere perfectly. However, the final DVD render had the audio lagging a little now. I guess Premiere is just not efficient at previewing audio and HD video at the same time and keeping everything in sync on the timeline. This is a pretty robust system too...4GB Ram, Quad-Core PRocessor and fast drives. My sound card (SB Audigy 2) is probably the oldest component. Anyone know of a good modern card to replace it? Thanks.

February 15th, 2008, 09:50 AM	#10
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	Sounds like a typical Premiere problem. Really, I had so many issues with Premiere that I jumped ship to Final Cut Pro. Which I do not regret as I have had no issues and no crashes with Final Cut under Leopard. In the six months before I spend too much of my time on problem solving. It might have been my computer, it might have been Premiere... but it didn't work.

February 15th, 2008, 01:22 PM	#11
Steve Tedesco New Boot Join Date: Oct 2007 Location: Setauket, NY Posts: 8	Had a out of snyc problem with my xl2 and FCP, had camarea set at rec-run and FCP set to make new clip at time code break. had old footage on tape, there was a break in the time code then after that it was out of sync. went back and captured again without making new clips and it was fine