Think I've been a bit of a noob (memory card question)

Jotun

Jotun

Jotun

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Hi guys,

I've recently bought a HD video camera which has been working OK, it's just when in a car the audio crackles quite a bit. I was just having another look at the advert and realised that the advert starts "SDHC class 6", but the card I have in it is a class 4. Is this likely to be the cause of the audio problems?

If so I'll happily buy another memory card, I just don't want to waste money if its a problem with the camera which I will end up returning...

Here's the advert in question:


And here's a short clip with the crackling present:
http://s55.photobucket.com/albums/g137/robeccleston/naff sound/?action=view&current=Movie_0007.flv
(Excuse the lame video)

Thanks :)
 
The class of the memory card basically defines how 'fast' the card is to read/write. The smaller than class number, the faster. So in your case of using a class 4 card for a class 6 minimum system isn't going to contribute to the audio problem.

I'd say it's the vibration from the car movement? Just a thought.
 
Either way, hardware won't have a minimum system, surely. It will have a maximum system , i.e class 6 is the fastest it can write, so a class 4 card will work in it, as it can write at class 4, so that is what i kinda thought Mr Jones was getting at.

Seeing as the crackling corresponds to the acceleration of the car, i would hazard a guess, at it being the fact the camera maybe be HD, but clearly has poor audio quality, and struggles with low end noise.
 
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Thanks for the replies guys, I did think it might have been the vibration too at first but I get the same outside the car, here is a clip from behind (about 10 ft away), where it isn't as noticeable but I can still hear it slightly.

If it's down to the memory card speed being too slow, should the problem go away if I try recording at a lower resolution?

The only other thing I could think it might be would be electrical interference from the engine, but I'm pretty sure I've seen clips from other users of the same camera which is taken in car without the same problem. And similarly I don't have this problem taking videos on a compact camera so I think it's unlikely.
 
asim18 said:
Yes definately.

What bitrate are the original videos?
Click to expand...

According to quicktime, 12.63Mbps. If I'm not mistaken, Class 4 should write data at 4 MB/s which is 32Mbps?

So I wouldn't expect that to cause the problem, just looking at those figures. But then on the other hand I've found than in an SLR the maximum write speed to a compact flash card will drop as the card fills up, although I don't know how relevant that is here :p
 
Jotun said:
Thanks for the replies guys, I did think it might have been the vibration too at first but I get the same outside the car, here is a clip from behind (about 10 ft away), where it isn't as noticeable but I can still hear it slightly.

If it's down to the memory card speed being too slow, should the problem go away if I try recording at a lower resolution?

The only other thing I could think it might be would be electrical interference from the engine, but I'm pretty sure I've seen clips from other users of the same camera which is taken in car without the same problem. And similarly I don't have this problem taking videos on a compact camera so I think it's unlikely.
Click to expand...

One thought that went through my head was that it could be affected by the electrical interference of the engine, like a stereo would be, like if u ran amp cables to close to car internal electricals, but i dismissed it as being to far from a strong source. Having listened to the vid again, its not that loud, but what sound could u get or what could u get inside a car you wouldn't outside. Could the very confined space and air pressure inside the car cause the audio to become worse when dealing with low bass.
 
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ChroniC said:
One thought that went through my head was that it could be affected by the electrical interference of the engine, like a stereo would be, like if u ran amp cables to close to car internal electricals, but i dismissed it as being to far from a strong source. Having listened to the vid again, its not that loud, but what sound could u get or what could u get inside a car you wouldn't outside. Could the very confined space and air pressure inside the car cause the audio to become worse when dealing with low bass.
Click to expand...

Thanks for the reply, I was wondering this but I had the same issue in my old car and yet I'm sure I've seen a clip by someone else with the same camera in another car without the problem which leads me to think it's more likely to be my camera.

Hopefully giving it a go at 720p will answer the problem as there will be a lower bit rate so if it is fine then its the card, if there's still a problem then it's the camera or interference.
 
Do you have an external mic you can borrow off someone to test with the camera? Sounds to me like the internal mic is just having problems with that particular noise range, as ChroniC said.
 
It's a cheap camera so no option for an external mic :(

I could take it apart and solder one in I'm sure but that'd invalidate the warranty probabaly :p

I've given it at go at 720p and I still have the same problem - Video here.

The other thing that's confusing me is that I also took a video of a car we made at university, and the audio on that is fine clicky. It was a lot louder than my car in my drive. I had the same problem in my old Astra when I took a video from the interior.

I guess it looks like its just down to the microphone then?

It's kind of annoying as I'm heading off tomorrow to a Japanese car show where there will be lots of cars including a convoy of ~230 MR2s which I was hoping to get some footage of. I suppose I'll have to just dub some music over the whole thing :D
 
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