Strange audio problem

T

tompa

Member
Yesterday I was filming one event in theatre without any visible problem due filming.But, during editing, I am find the audio is distorted from about 1 hour and 31 minutes to end (about 3 minutes). I use two microphones, 1st chanel from camera and second is audio-technica ATR25 and distorsion appears on both chanels!!!At home, I am testing camera without any problem, sound is as usually. Has anyone had a similar problem or anyone know something about that? Here is link on youtube, distortion start from 6. second:
 
Your video is set to "private" so I can't listen to your sample.

I have to ask, though... why are you trusting your audio to "visible problems" during production? Sound is not a visual aspect of the medium, so why are you trusting your eyes and not your ears? Were you not wearing headphones and actively listening while you were recording? That's the only way to detect audio problems and keep them from being surprises in post-production.

Distortion and other problems can happen in places before the camera's inputs. If the incoming signal is already damaged, your sound is going to be messed up no matter what the meters say.

Also, what's your complete signal chain? Are the mics connected straight to the camera, or are there any other pieces in the chain (external preamp, mixer) between the mics and the camera?
 
Sorry! Now is "public"! I mean no problems with SD card or audio level. Yes, my mistake is that I don´t use headphones. But, if you are listen sample, I don´t know what will I do if I hear that "noise"!
 
That's not distortion. That's data corruption... like the camera had a clocking error. Not sure what to tell you with that, except for future events run a second recorder as a backup.
 
Thanks Alex! And I thought it was something with the camera. I guess that is associated with a long, continuous recording.
 
The whole day trying to repeat the mistake and I can not repeat it. Camera recorded 5 hours straight and everything is fine! The worst is that I do not know if it will be repeated on the job!
 
Does it sound the same when playing the original clip directly off the SD card using a plain viewer program, or could this have been caused when transferring media or importing the data into your NLE?

What camera is that, BTW?

- Greg
 
I suppose the obvious question is to check that playback in the camera is also showing the same fault - to determine if the data error was created during transfer to your editor, or created in the camera. So there's a tiny bit of hope. Not a lot, but a small chance.
 
Unfortunately, I tried to play back on the camera and sound is the same. Error was created in the camera and recorded on SD card. Camera is HMC151, 2 years old, with 450 work hours.
 
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That's very annoying isn't it - I guess this will be tricky, because the fault hasn't been fixed, it's just temporarily absent - and even sending it for service can't guarantee it can be fixed unless they can make the fault appear. How about trying temperature changes - put it somewhere warm or cold and see if you can make it happen again?
 
I'm not sure that the problem is of high ambient temperature, in the theater was about 22 degrees Celsius. That is too low for any kind of overheat! It is more likely that a bug that can but not necessarily repeating, like in any computer. From now on I will, just in case, wear headphones.
 
Could be a SD card problem, too -- in which case you wouldn't have heard it during recording even if you had been monitoring with headphones. Just on general principle, I think I would retire that card.

- Greg
 
I do not believe that the problem with the SD card because then the image was corrupt too. Unfortunately, during the recording did not use headphones so I do not know whether it was heard on headphones. The same SD card I, the day after, all recorded and there was no problem!
 
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