K-5 video question


ChrisA

Link Posted 12/12/2013 - 12:42
Has anyone come across a situation where the audio and video are slightly out of sync?

I filmed a post-dance-class demo last night, and the couple teaching are both extremely good dancers (Argentine Tango, if anyone's interested), and it's inconceivable that they would ever be out of time with the music.

I certainly didn't notice anything while I was filming, and was only watching the LCD to make sure they were in shot.

Yet on the AVI file as uploaded, the audio seems a tiny bit behind. By tiny, I mean a tenth of a second or so, and I'm not even convinced that it's a real effect. I've watched it in VLC player, and opened it in Windows Movie Maker (yes, I know.. ), and they're the same.

Anyone seen this? I was very close to the action, and the speakers, far too close for any speed-of-sound effect.

I can't show you the video, unfortunately. Not a very good video, protection of reputation and all that.

As a supplementary question, is there any free software that would let me shift the soundtrack in an AVI file by a very small amount?
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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gartmore

Link Posted 12/12/2013 - 16:23
You can get a free trial of Sony Vegas which will do what you want and I recommend it as an editing package too. A tenth of a second isn't 'a tiny bit'.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

ChrisA

Link Posted 12/12/2013 - 16:36
gartmore wrote:
You can get a free trial of Sony Vegas which will do what you want and I recommend it as an editing package too. A tenth of a second isn't 'a tiny bit'.

Thanks, I'll take a look. It might not even be as much as a tenth - it's too small for me to make a sensible estimate. I've watched it a couple of times more now, and I'm not as convinced now that I'm seeing what I thought I was seeing. It just seems so unlikely...
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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MattMatic

Link Posted 12/12/2013 - 16:40
For audio editing, Reaper is top for me
Reaper.fm
Primarily a DAW it handles video too. Has nice noise reduction options - though of it is a bit buried in detail.
You can even stretch audio - useful for syncing a secondary audio capture with video.
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)
Last Edited by MattMatic on 12/12/2013 - 16:41

Don

Link Posted 12/12/2013 - 17:04
distance between the mic and subject could explain the problem..or your software/hardware playing back the video.. read up on "doppler effect"… I have noticed a slight difference in sync when doin a multi cam edit from large auditoriums where one camera at the back, and one at the front are used… it is always preferable to use an audio recorder taking a line feed off the venue's main soundboard for such work.

audacity(free), premier pro and FCPX are all capable of shifting/synching audio..
even in simpler programs like imovie it CAN be done (detach the audio then shift it or add spacer frames)..
Fired many shots. Didn't kill anything.
Last Edited by Don on 12/12/2013 - 17:07

gartmore

Link Posted 12/12/2013 - 17:47
I've often agonised for hours over this getting to the stage where I'm not even sure if the audio is ahead of, or behind the picture.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

Dave-L

Link Posted 12/12/2013 - 18:15
ChrisA wrote:

As a supplementary question, is there any free software that would let me shift the soundtrack in an AVI file by a very small amount?

The freeware Virtualdub handles AVI/MJPEG + PCM/wav files well for this kind of thing and lets you alter the audio interleaving/sync + or - by any amount.

It will save the video and audio unchanged, except for the altered interleave/sync if you choose Direct Stream Copy. HD is no problem for it. One advantage of K-5 video over K-3 video, in my book, is its use of avi which is more widely compatible than mp4, especially with established freeware.

I've used it to solve this kind of problem (and more) for a decade or more, you don't even need to install it as such, just run it from the .exe after unzipping into some random folder. If you want to know the exact settings to use, let me know. http://www.virtualdub.org/index
K3/K5/10-17fisheye/15mmDA Ltd/18-55WR/55-300DA/100DFAMacroWR/50F1.4M/200F4M/300DA*F4/Mitsuki 400F5.6/others.
Last Edited by Dave-L on 12/12/2013 - 18:44

ChrisA

Link Posted 12/12/2013 - 19:19
Don wrote:
distance between the mic and subject could explain the problem..or your software/hardware playing back the video.. read up on "doppler effect"… I have noticed a slight difference in sync when doin a multi cam edit from large auditoriums where one camera at the back, and one at the front are used… it is always preferable to use an audio recorder taking a line feed off the venue's main soundboard for such work.

audacity(free), premier pro and FCPX are all capable of shifting/synching audio..
even in simpler programs like imovie it CAN be done (detach the audio then shift it or add spacer frames)..

Cheers Don... I was about 15 feet from the dancers, and about 30 feet from the speakers.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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richandfleur

Link Posted 12/12/2013 - 19:23
Yeah as above, in a video editing program you'd unlink the video from the audio and then you are free to move either independently as required.

sbrads

Link Posted 13/12/2013 - 11:39
ChrisA wrote:
Don wrote:
distance between the mic and subject could explain the problem..or your software/hardware playing back the video.. read up on "doppler effect"… I have noticed a slight difference in sync when doin a multi cam edit from large auditoriums where one camera at the back, and one at the front are used… it is always preferable to use an audio recorder taking a line feed off the venue's main soundboard for such work.

audacity(free), premier pro and FCPX are all capable of shifting/synching audio..
even in simpler programs like imovie it CAN be done (detach the audio then shift it or add spacer frames)..

Cheers Don... I was about 15 feet from the dancers, and about 30 feet from the speakers.

That's under 30ms delay.

Don

Link Posted 13/12/2013 - 19:26
yeah it has to be a substantial distance to be perceptible… sound travels at 340.29 m / s
Fired many shots. Didn't kill anything.

DaveHolmes

Link Posted 20/12/2013 - 00:16
MattMatic wrote:
For audio editing, Reaper is top for me
Reaper.fm
Primarily a DAW it handles video too. Has nice noise reduction options - though of it is a bit buried in detail.
You can even stretch audio - useful for syncing a secondary audio capture with video.
Matt

Not used Reaper with video but for anyone with an interest in music production and on a fairly tight budget it is incredibly capable daw indeed!
I've got the Pro version of Presonus Studio One now so haven't used Reaper for a few months but as Studio One's support of video is sadly lacking (a shame because it's audio engine sounds stunning!) I'm glad I still have Reaper installed!
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