# SDHC card question



## HossHuge (May 24, 2011)

I have a 1080p (24Mbps) video camera and I use a Transcent 8GB class 6 SDHC card with it.  I notice micro stuttering when I record longer videos.

Does this mean I need a faster card?


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## VulkanBros (May 24, 2011)

Is there higher classes than 6 in SDHC cards?


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## Sasqui (May 24, 2011)

HossHuge said:


> I have a 1080p (24Mbps) video camera and I use a Transcent 8GB class 6 SDHC card with it.  I notice micro stuttering when I record longer videos.
> 
> Does this mean I need a faster card?



Typically 1080p video is recording at ~2-3MB/s, which is well within even Class 2 capability.  Though some of that depends on the final format being written.  Perhaps a buffer issue with the camera...

Do you have a different card you can try?

Edit:  I found this:  http://www.t2iforum.com/video-speci...ss-4-and-class-6-not-working-for-1080p-video/

"...Tried shooting video in 1920x1080 in 30fps and 24fps and 1280x720 on both my kingston 4gb class 4 and transcend 4gb class 6... 

all my videos are very choppy even after formatting both cards and shooting on a freshly formatted card... If I had to guess the kingston class 4 is too slow and the transcend class 6 is too cheap of a brand. ..."

So perhaps even the Class 6 cannot handle it in real-life (forget theoretical bandwidth!)


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## 95Viper (May 24, 2011)

VulkanBros said:


> Is there higher classes than 6 in SDHC cards?



Uh-Huh... goes up to class 10, so far.

_______________________________________________________________________________

Some info that will help from over at the SD Association:

SDHC Memory Cards

There are two kinds of Speed Class, "Speed Class" and "UHS Speed Class.

Frequently Asked Questions

SD Formatter 3.0 for SD/SDHC/SDXC

SD Formatter 3.0 for SD/SDHC/SDXC User Manual
_______________________________________________________________________________

@Newegg: Class 10 Secure Digital High-Capacity (SDHC) Flash Card

Don't get one that says fast, my not be necessarily so, research it out.


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## jsfitz54 (May 24, 2011)

I like the *Patriot brand SDHC Class 10* cards and have 2 x 8GB cards and a couple of smaller Patriot ones, Class 6.

Also have Class 6: Crucial, Sandisk, Kingston and OCZ...never had one fail yet.

What brand did your camera come with? ie, sample card?  Only as a guide as to what the Vid Cam company gives a passing grade for card(s).

I would think a Camera or Vid Camera review site might offer you better info on the newer Class 10 cards.


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## HossHuge (May 25, 2011)

Sasqui said:


> Do you have a different card you can try?
> So perhaps even the Class 6 cannot handle it in real-life (forget theoretical bandwidth!)



I've tried two class6 cards and both have the same issue.



95Viper said:


> SD Formatter 3.0 for SD/SDHC/SDXC
> 
> Don't get one that says fast, my not be necessarily so, research it out.



I've been using the SD card formatter for awhile now but I didn't know they had an up-date...thanks!

The one constant I've read in the research I've done this week is that no one knows if their device is able to use the faster cards properly..... 



jsfitz54 said:


> What brand did your camera come with? ie, sample card?  Only as a guide as to what the Vid Cam company gives a passing grade for card(s).


It never came with a card .  The store I bought it at gave me a Silicon Power 8gb class6 card with it.


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## yogurt_21 (May 25, 2011)

1080p bit rate is dependant on the capture speed in fps of your camera. typically this is 15fps.

http://web.forret.com/tools/megapixel.asp?width=1920&height=1080

most home video cameras capture in jpg90 which equates to 5.5MBps at 1080p. Likly your sd cards are overrated and aren't hitting full speed hence the stuttering, that or your camera does 1080p HQ which is 30fps for which you need a 100x or better rated card. The classes are useless for judging sd card speed. Try and find the actual bit rate. For instance I have some older 2GB 133x kingston sd cards, 133x = 160Mbps = 20MBps. I also have a 200x 16GB card for my video camera, 200x = 240Mbps = 30MBps. 

http://en.wikipedia.org/wiki/Secure_Digital

so find the x rating, multiply it by 1.2 and that gives you megabits per second, then divide by 8 for megabytes per second. 

I have a standard class 6 card for my 14mp camera that also did 720p video. The videos would be stuttery at playback. Come to find out my camera does 720p at 30fps. So I popped in the above mentioned 2GB card and no worries. 


.....tldr = your card is too slow, buy a 100x or better SDHC card


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## HossHuge (May 25, 2011)

I decided to do my own tests with a 701MB video file.

They're all Class 6 cards.

Apacer 4GB - 1.13 sec_________ avg about 9.6 MB/sec
Silicon Power 8GB -  1.11 sec____avg about 9.9 MB/sec
Transcent 8GB - 57 sec_________ avg about 12.3 MB/sec

Panasonic 2GB Class 4 card - 1.30 sec__avg about 7.8 MB/sec

They all easily go over their class distinction.   

I've decided to pick up a 16GB class 10 card and use the Transcent as a back up.

Thanks All....


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## Sasqui (May 25, 2011)

HossHuge said:


> I decided to do my own tests with a 701MB video file.
> 
> They're all Class 6 cards.
> 
> ...



Hey Hoss, if you happen to remember, post an update when you try the new card.  

Cheers.


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## HossHuge (May 27, 2011)

I picked up a SanDisk 16GB Extreme today and I noticed that it is smoother.  I also noticed that it seems the focusing of the video camera is faster for some reason.  

I did the same test as before and the ScanDisk did it in 43 secs at 16.3 MB/sec.

I though it would be much faster but I'm not sure if there is some sort of limitation on the card reader.


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## Mussels (May 27, 2011)

HossHuge said:


> I picked up a SanDisk 16GB Extreme today and I noticed that it is smoother.  I also noticed that it seems the focusing of the video camera is faster for some reason.
> 
> I did the same test as before and the ScanDisk did it in 43 secs at 16.3 MB/sec.
> 
> I though it would be much faster but I'm not sure if there is some sort of limitation on the card reader.



AFAIK the class ratings on the cards is more about their minimum speed - and i think they suffer the same problems as SSD's, in that they need to use buffer/cache and write in big lumps.

so even if you're only needing say, 3MB/s of bandwidth, getting 10MB/s gives you far more room to get past those little annoying stutters leaving enough room for it to catch up.


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