04-26-2019 10:21 PM
I don't have enough knowledge to be able to answer the how and why of limitations with devices and SD cards. However, awhile back I started outlining some of the info I came across regarding SD cards. I might put this in long form or make a video about it, but for now, here is what I've got.
When you put an SD card in your camera it becomes a part of the camera
Figuring out the differences in SD cards and why it matters
Write Speed vs advertised Read Speed
Knowing what information they are giving you and what they aren’t telling you.
Why speed matters
“Recording video require a constant minimum write speed to avoid 'frame drop' during recording for a smooth playback”
If constant write speed is not maintained, freezing and overheating can occur as the processor gets overloaded
Currently there are 3 different Speeds Classes, the same but different
Speed Class 10, U1 and v10 all equal a minimum of 10 MB/s write
Speed Class (Class 10)
2, 4, 6, 10MB/sec
U speed Class U1 and U3
U 1 - Good for HD video 720p, U-3 for =>1080p and faster fps
BUT THERE IS ALSO UHS!! Often described along with U speed class but this is confusing as there is UHS-I, UHS-II, and UHSIII
UHS isn’t the speed rating but the transfer bus being used
Cards are usually designated with UHS-I, UHS-II, or UHS-III to designated what interface is used ***Most cards on the GoPro recommended list are UHS-I. While UHS-II and UHS-II are designed to be backward compatible and can utilize the UHS-1 interface, it’s probably best to choose UHS-I as this most likely will give the best compatibility
V speed Class/Video Speed Class
All about Sustained performance
V or Video Speed Class supports "Suspend/Resume" function that can stop and retrieve sequential write. By using the function, it is possible to improve memory usage
Video write speed is different
Example: SanDisk Extreme v30 32GB has listed write speed of 90 MB/s; however, when you read the fine print it states, “Video Speed Class 30 (V30), sustained video capture rate of 30MB/s”.
Conclusion: When comparing cards, Read Speed and Write Speed don’t tell you enough. You need to know the Sustained Video Capture Rate.
Clarifying MBs vs Mbs
Mbs = Megabits per second
MBs = Mega Bytes per second
1Megabyte = 8 Megabits
60 Megabits = 7.5 Megabytes (HERO5 Black)
78 Megabits = 9.75 Megabytes (HERO7 Black**in HEVC)
So why do we need so much write Speed?
bit rate and data rate are two terms used interchangeably
Data rate is the amount of data in bits per second of footage, measured per second and expressed as bits per second
But… Bit rate is the number of bits per second of footage, measured per frame or field, also expressed as bits per second.
Data does not just flow through the lens and land on the SD card, the information is processed and then written to the card.
Mb/s is what you will SEE when watching the video and is representative of the data per second of the video, this is not necessarily indicative of the amount of data being written at any given time. The camera processor is receiving data, computing it and then spitting it out to the SD card.
SD association recommends roughly between 30MB/s – 60MB/s for 4K recording.
SLC, MLC, & TLC (the closely guarded secret)
SLC (Single Layer Cell)
Endurance of SLC Flash is 10x more than MLC
Can operate in an industrial temperature range
Example (Panasonic SC)
MLC (Multi-Layer Cell)
More cost effective
Increased sensitivity required to differentiate between the levels
Extreme temperatures cause more leakage in the cells causing the sensors to read the wrong level
Examples (Panasonic KC, Samsung Pro/Evo Plus and SanDisk Extreme)
TLC (Triple-Layer Cell)
Far less dependable
More prone to error
Sensitive to extreme temperatures
Examples (Panasonic LF & MF, Samsung Evo and SanDisk Ultra)
Proper care and keeping the connectors clean
By repeating deletion and write of files, data area is gradually fragmented and it influences write speed. Generally, write speed to a fragmented area is slower than sequential write speed due to flash memory characteristics
How to Format
In your computer
Full vs Quick
Left Over Files (LVR Thm)
Folders and camera data files
In the Camera
See “recommended” SD card list
SanDisk Extreme v30
SanDisk Extreme Plus
SanDisk Extreme Pro
Samsung Evo Plus
Samsung Evo Select (not listed but the same card as Samsung Evo Plus)
These are Tested cards (not a list of the ONLY cards that you can use)
Why only use a recommended SD card?
Prevent frequent “issues”
Freezing during recording
Lock-up while in menus
Unusual Battery drain
Helps to identify manufacturer issues vs SD card issues
99% of issues are SD card related
Allows GoPro Support Team to rule card out
Recommended SD cards can have issues
Always try a second SD card if possible
Full format in your computer (checks for errors) followed by format in camera (creates proper tables)
Choosing the right storage capacity
Battery life and needed storage capacity
Cards that I use and why
A word about SanDisk
Most frequently sited card with people reporting issues
Most Popular brand, so could account for frequency
GoPro Board member also on SanDisk Board
Chairman, SanDisk - January 1, 2011 to May 12, 2016
Director at GoPro, February 2011 to June 6, 2017
My history with SanDisk and camera issues
HERO3 Silver (with SanDisk Ultra)
Camera not turning on
**Switched to Lexar 633X and issues went away
HERO5 Session (with SanDisk Extreme)
**Switched to Samsung Pro UHS-1 and Lexar 1000x and issues went away
HERO5 Black (SanDisk Extreme/Pro/Pro Plus)
GoPro Community reported issues
**Only used Samsung Pro, Pro Plus and Lexar 1000x and had no issues
HERO6 Black (SanDisk Extreme v30)
Initial issues with Samsung Pro Plus and Lexar 1000x
Firmware update fixed issues but I has purchased SanDisk Extreme v30 during this time to test it out
Finally a working card!
HERO7 Black & White (SanDisk Extreme v30)
1 of 5 (20%) causing freezing & Unusual Battery drain
Son’s HERO7 White Freezing in menus and Stopping recording after 1 minute of recording
Put in HERO3+ Black and got SD ERR notification
HERO7 Black & White (Samsung Evo Select)
Reports (on forum) of camera temperature lower when this card is used
No issues experienced personally
04-27-2019 03:18 AM
Short and sweet to the Point. never put all your Eggs in one Basket. use the 128 gb card and dump off or get a spare then one big card. 256gb card is hte max if it does not work gopro has a reason why not us????
05-09-2019 12:08 PM
Well, I'm using 512 card.
Playing with the cards, is not my target.
Just want to use it all the day long, just supplying more power.
And... changing the card, while riding a motorcycle, isn't too easy.
05-10-2019 12:14 AM
What are you doing with half a Terabyte of media? Since 3 hours of recording is equal to a little less than 128GB, a 512 GB card is going to record more than 12 hours of video. Who has time to watch and edit that much footage? If it's just for safety recording, try looping mode. If you want the footage for creating videos, maybe try recording only important moments (again, you could just set the camera to something like 5 min looping and each time something you want to keep has happened, stop recording and start a new recording). If access to the camera shutter is difficult or not possible, get a Smart Remote and either mount the remote to a convenient location, or just strap it to your wrist.