Video Stream Freezes at random Photo Capture
- Phone: iPhone 11pro, iOS 14.7.1.
- Dronelink iOS client 2.4.3 (159), kernel 2.4.1.
- Mavic Air 2, f/w 01.01.0610 (4/15/2021)
At a random point in the mission, the live video sometimes freezes immediately after taking a photo (i.e., live video is frozen, showing photo just taken). This doesn't happen every time the mission is run; rather sometimes the entire mission completes with live video working fine. It has happened in multiple missions, so it isn't specific to one mission. It does not happen at the same photo -- sometimes on the first, sometimes on the second, etc., and sometimes the entire mission completes without a video freeze.
When the live video freezes, the mission continues normally, proceeding to additional destinations, taking additional photos (complete with shutter sound effect), and completing successfully -- still showing the same frozen photo instead of live video. The other indicators in the client (i.e., altitude, speed, etc.) continue to be updated normally; it is only the live video feed that is frozen.
The component taking the photo consists of:
- Camera Stop Capture
- Camera Mode: Photo
- Camera Photo Type: Smart
- Camera Start Capture
- Camera Stop Capture
It isn't related to a specific mission, and the missions are in a private repository. It most recently happened on the first photo taken in the following mission: https://app.dronelink.com/sw108w/mission/muTjU86GmXY2HNJCO6mG
Comments
8 comments
Does it happen on a different mobile device?
Haven't tested on another mobile device. Are you suggesting that an iPhone 11pro (A13 cpu) isn't powerful enough for Dronelink?
I do have an IpadPro-11 gen2 with A12Z chip which (maybe? I think?) is slightly faster than the A13, but at 11" it doesn't fit the Mavic Air 2 controller. I can look at 3d printing a mount extension or something I guess.
I'm wondering if the problem might be related to the length of time a "Smart" photo takes -- which can vary a bit, but generally takes longer than a "single" photo. It is normal (in DJI Fly also) to see a short ~1s freeze when a photo is taken before resuming the live feed. If that requires any code action when the capture is complete (like an explicit "return to live feed"), then perhaps that is happening before the capture is complete, and failing to restart the live feed?
I've changed all the "Smart" photos to "Single" in that mission, and will run it a few more times to see if that makes a difference. The problem is intermittent, so I may need to run it several times to "prove" or "disprove" any difference from the photo type. If I can figure out a way to mount it, I will also give the iPad Pro 11 a try.
No
Likely
After changing all the photos from "Smart" to "Single", I've run the mission twice. That really isn't enough to be conclusive since the problem was intermittent, so I'll run it a few more times -- but at least in those 2 missions, no freeze occurred. I'll run it a few more times and report back with results.
After changing the captures in the mission (there are 10 captures in a ~7 minute mission) to "Single" mode, I have run the mission (8) times now. No video freezes.
The problem when set to "Smart" was intermittent, and sometimes the mission would complete without any freeze. But I'd usually get the video freeze at least every 3rd time the mission was run. Therefore, running it with "Single" (8) times and having zero problems leads me to conclude the freeze is related to taking "Smart" photos.
The "Single" photo mode executes quickly: The video pauses, the shutter sound is heard, the capture button animates for less than a second, then video feed resumes. The "Smart" photo mode varies from 1 second to nearly 3 seconds, I guess depending on what process the firmware decides to use for that particular scene and lighting. Perhaps the long delay isn't always playing well with Dronelink?
Here is DJI's explanation of what "Smart" does, which presumably is why it can take 2-3 seconds while a "Single" mode photo takes less than 1 second. I'm assuming that's all done in firmware, since the final photo is stored on the drone's SD.
The video preview is from the DJI UXSDK, so it sounds like they have a bug wrt smart photos. Will report it to them.
Thanks, Jim.
Does DJI use that same UXSDK for DJI Fly? I ask because I've been using DJI Fly for over a year, and have never seen a video freeze there. But maybe they use something other than the published SDK?
I pretty sure they have a completely different code base.
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