# Canon 6D video "hiccups"



## Skywise (Jan 19, 2016)

I've noticed when taking longer videos with my 6D (greater than 5 minutes) that the recorded video stutters occasionally (audio stays fine) as if the write buffer is full or the bandwidth at that particular point in the video went too high. 

I'm using a class 10 San Disk Pro 128gb memory card (although I've seen this on all the memory cards I've used) and I format it before each use and the card wasn't even 1/4 full.

Does anyone else see this? I usually see it with night videos (fireworks, shows) with lots of activity at the time so I'm leaning towards a buffer overflow issue but I'm wondering if it's not a problem specific to my camera.


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## ajfotofilmagem (Jan 19, 2016)

You are shooting in mode IPB, or ALL-i?
ALL-i recording requires a card with minimum sustained bit rate of 20 MB per second.

I believe the UHS-I U1 cards are not fast enough for that. I use UHS-I U3 card for this type of recording.


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## Skywise (Jan 20, 2016)

Thanks - 

Running IPB 1920 30fps

It's a SanDisk Extreme Pro 128gb 95mbps and is marked as U3. (I got it around spring of last year - Before that I had a U1 Patriot EP 128gb but upgraded to the San Disk because of the hiccuping thinking the Patriot might not be fast enough)


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## Mt Spokane Photography (Jan 20, 2016)

Make sure you low level format the card. A regular format does nothing except erase entries in the Fat Tables, the card still has the remnants of files written to it previously, and is likely full. 

The card has to be erased block by block as part of the write process, and that will make it very slow. A low level format erases the card memory cells, so it will regain new and rated speed.

People get fooled all the time by the specifications for SD cards without knowing the gotchas.


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## Skywise (Jan 20, 2016)

Should I do the low level format after every shoot? I thought the basic format would be enough.


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## ajfotofilmagem (Jan 22, 2016)

Skywise said:


> Should I do the low level format after every shoot? I thought the basic format would be enough.


As Mt Spokane said, SD cards have a write speed specified for the condition of "brand new".

With normal formatting, the data remains on the card, and need to be effectively erased during recording of the images. It needs to do a low level format every time, to restore the specified recording speed.


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## Mt Spokane Photography (Jan 22, 2016)

Skywise said:


> Should I do the low level format after every shoot? I thought the basic format would be enough.



Buy a very large card. Why would you format it? Is it too full to do another shoot. If so, do a low level format. If it has plenty of space left, don't format it, use it until remaining space is limited and do a low level format. That keeps it out of the overwrite mode.

A in camera format makes the files invisible to you, but they are still there. That's why file recovery software works, it merely asks you to provide a name for the files and copies them to your computer.

The card itself has a controller internally that tries to give equal use to all memory cells, so additional files are usually written to the blank cells before overwriting existing ones, but its sporadic, so you see hiccups' as it decides to overwrite cells and slows way down.

That's why pros prefer CF cards, you don't see that happening, and don't need to low level format to regain your speed.


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