Intermittent dropped video frames, think I finally found the cause

Joined
Nov 6, 2015
Messages
1,400
Reaction score
566
I have been seeing intermittent dropped video frames, usually around 30 at a time, in 4K recorded video. I was using one of the 64 GB SanDisk Extreme U3/V30 cards that is both on the DJI approved list and has earned good reports on the forum so initially I assumed that it wasn't the problem, but after being unable to find any other cause I compared to the 16 GB Panasonic card that came with the P4P and lo and behold, no problem when using the Panasonic card. I then had the SanDisk card replaced under warranty with an identical unit and so far I have been completely unable to duplicate the problem, so it appears that I did have a defective SD card even though it was new. The card wasn't counterfeit since SanDisk approved the s/n and warranty RMA so it looks like I simply got a bad card, unlikely but it does happen. Something to think about if you are having intermittent video glitches... check your card against another known good unit even if you are 'sure' it is OK.
 
  • Like
Reactions: Davidnclearlaketx

alokbhargava

Premium Pilot
Joined
Sep 28, 2015
Messages
6,943
Reaction score
2,325
Location
San Francisco, CA
Joined
Nov 6, 2015
Messages
1,400
Reaction score
566
Yes, a test program can be very useful although not absolutely conclusive. Since I could clearly isolate the problem to the SanDisk card there were only two possibilities, either the card was defective or it was inadequate based on specs. The latter is not the case so the former was the most likely, and seems to have been proven out. Unfortunately I no longer have the original card but it would have been interesting to examine it with a test utility.
 

alokbhargava

Premium Pilot
Joined
Sep 28, 2015
Messages
6,943
Reaction score
2,325
Location
San Francisco, CA
I cant tell you to try it next time :)
 
Joined
Nov 6, 2015
Messages
1,400
Reaction score
566
Just for grins I tried the test utility on the SanDisk and Panasonic cards. The SanDisk performed very well but the Panasonic card seemed to have a limited write speed, even though both are U3 cards. Tests were done with the same Transcend USB3 card reader in a USB3 port.

Warning: Only 1000 of 60874 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 63.3 MByte/s
Reading speed: 71.5 MByte/s
H2testw v1.4

Warning: Only 1000 of 15272 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 9.80 MByte/s
Reading speed: 68.6 MByte/s
H2testw v1.4


Since the card reader and USB port and PC were identical for all tests it seems that either the Panasonic card is slow or there is some peculiarity with the test software.
 

alokbhargava

Premium Pilot
Joined
Sep 28, 2015
Messages
6,943
Reaction score
2,325
Location
San Francisco, CA
Great !

Writing speed of 9.8 MB/ s is too slow. Was the test correct?
 
Last edited:
Joined
Nov 6, 2015
Messages
1,400
Reaction score
566
Writing speed of 9.8 MB/ s is too slow. Was the test correct?
Can't say, other than I ran it exactly as I did for the SanDisk card. Tried a few times, always the same result. The Panasonic card (U3 rated) seems to function well in the P4P so I doubt it's really that slow, perhaps an issue with the test software, just don't know.
 

New Threads

Members online

No members online now.

Forum statistics

Threads
141,868
Messages
1,458,831
Members
103,659
Latest member
88bobby