ScottyT
Second Officer
New Zealand
Offline
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Well, I'm just a hobby technologist, but I think it is doing a LOT more than bringing in the video!
Like what? What is the tablet actually doing?
The older Analog video FPV stuff just sent a stream to the monitors (analog also) which work something like a TV screen - scan lines, etc.
Lightbridge is a digital signal which sends a large stream of raw digital data to the device - not just video that's already been processed (youtube, etc.). The video has to be processed and then rendered. This is why digital video streams on quads have more lag than analog - time and CPU and GPU power needed on both ends.
So the RC unit does nothing at all in the mix? No smarts...it leaves all processing up to the tablet? And it's a low framerate 720p feed, nothing special. And that's not the reason for the lag.
One reason - I think - that IOS works better is because there is an option in the DJI IOS app to make use of "hardware decode" in the IOS device. This may show that IOS had some addressable hardware which is probably not available on Android - Android has to use software tricks to do the same thing.
All tablets have addressable GPUs. People are turning on hardware decode where once they didn't have to - allegedly since a firmware update. These are all steps being performed because of issues with the app, to claw back resources.
As to people having to purchase high end devices - here is my opinin FWIW.
I started with a $30 Android Moto-g - which works OK. I am now using a Nexus 7 II which also works good enough for my use. So those are 2+ year old devices.
However, considering that before the P3 we had absolutely nothing to compare (in any way) to this range and video-feed quality, how can we state that an old...or even new..device should work flawlessly? isn't it like other high requirement stuff (OCR, Voice Recognition, video editing, etc.) where the technology is somewhat ahead of the hardware...or at least requires the best?
No. The bird is off, there is NOTHING to do and is thus not "High Requirement Stuff" - You can't be comparing it to a workload where CPU cycles would actually be required. People would be understandably upset if their OCR or Video editing app was cooking their devices when it was not actually performing any practical task.
The RC is providing the lightbridge and range, not the tablet. It's a low fps 720p feed, is all...when it's on. It's comparable to anything displaying 720p or higher from a digital format.
As far as high CPU use when not doing anything, I don't think that's an accurate metric. My task zapper program takes up 50% sometimes when I open it an kill tasks....the pilot app is not designed to run without the bird so it could be trying to do a lot of fruitless things.
50%...so, at what frequency step, for how long, how much does it heat up the CPU/Tablet? Describe your metric better. The DJI app has nothing to do with the bird turned OFF.
I'm not claiming that the app cannot be made more efficient. However, the question I ask is whether folks would have preferred that DJI release a less capable (lower res, lower fps, less telemetry, etc.) app to satisfy everyone? It seems the more we get, the more we want. You would have spend $3500 for the Inspire and a good tablet - now we are complaining about spending $1K and perhaps $300 for one.
No we're complaining because the app is badly coded and even high end tablets are lagging. There's no point buying a Porsche when all you need is a Mini.
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