Xiaomi console access

Andy_S

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#61
well, i heard this:
wifi off: low pitch, low volume "rumbling" - direct memory access (image data being processed & stored into RAM), every ~5second two high pitch higher volume "squeaks" - writing to SD card

wifi on: same as before, this time the rumbling sounds more like scratching. Tiny "clicks" in background is wifi. broadcasting SSID.

moving: well, by moving i meant more rapid moving to "hear" if something is loose inside camera, but i doubt that.

From what i heard i can tell, that xiaomi didn't do proper job for filtering (capacitors) power lines to the ambarella chip (or whatever manages audio). Its caused by "cheap circuitry" in power source that isn't stable enough and the fact that there aren't enough capacitors properly placed near the processing chip. You can commonly hear these sounds in cheap soundcards mostly in laptops or older computers. But then this camera was never intended as a hifi audio source, its audio is just an addition to the picture. If you want hifi audio solution, you need to grab something different.

If you meant these rumbling / squeaking sounds as them "clicks", then i am affraid no shielding will most probably help you since they are caused internally... Note, that these sounds intensify with WiFi on, which means increased power consumption = bigger load on the power souce = bigger unstability = more pronounced noise.

Oh and this noise also induces into the image sensor as well, luckily there is huge ammount of software post-processing involved for picture, not so much for sound
 
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#62
looks like you've been working with this kind of stuffs for a very long time that you have associated those sounds to the actual process. Amazing! :D

Yes that's what I am hearing... The scratch sound if you may call it and the clicks. I don't really want a hifi audio but I don't want to hear them also. Those sounds decreases as they blend with the backgroud audio till you can't hear them anynore. But with people who has sensitive hearing it's a different story, it's annoying...
 

Andy_S

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#63
Maybe it will be possible to filter it out by adding some more capacitors on the power lines, but without schematics its a very risky job.
 
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#68
it does work (rawtodng and then open the dng in photoshop). the end result is just a bit **** (wrong colours and exposure, overblown highlights turn magenta). It doesn't seem to have much more dynamic range than a jpeg.

I am not sure it's a real bayer RAW file, might just be YUV.
 

nutsey

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#69
(wrong colours and exposure, overblown highlights turn magenta). It doesn't seem to have much more dynamic range than a jpeg.
That's exactly what our camera receives from the sensor - pure RGGB data without any header or calibration info. And it explains the amount of post-processing applied.

I am not sure it's a real bayer RAW file, might just be YUV.
Please don't confuse a camera RAW file of common format (NEF, ORF, DNG...) with pure RAW sensor data.
 

zachnfine

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#70
Has anyone yet managed or tried to do the following after telnetting in to the Yi:

  1. Manually set the shutter speed
  2. Manually set the aperture
  3. Manually set the ISO/gain
  4. Manually set the white balance
  5. Trigger the camera to start recording

I read through the list of autoexec commands that were posted to github and am super-intrigued. I don't know if those commands are only available to be added to an autoexec file read by the camera at startup or if they can possibly be used in a telnet session.

My Yi's on order, so I look forward to trying to take manual control of the thing's functions over telnet.
 

Andy_S

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#71
they are executed by ambarela before launching busybox to which you are telnetting into...
 

zachnfine

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#74
that is unknown yet, but don't bet your money on it...
Well, I bet the cost of the Xiaomi Yi on it. I guess worst-case I'll still have a decent little action cam to play with.

With any luck, they left something accessible from the shell that can adjust camera settings. I'm holding out hope.
 

Andy_S

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#75
well, i am also waiting on my camera(s) and when they will arrive, i will put them under HEAVY hacking ;)
 

zachnfine

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#76
well, i am also waiting on my camera(s) and when they will arrive, i will put them under HEAVY hacking ;)
I don't suppose Xiaomi has posted any source code for modifications to busybox –if they've made any they may be available. I believe busybox is GPL'd.
 

Andy_S

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#77
they are using some of their daemons, for example network_service_daemon (or whats the name) taking care of ports 7878 and 8787 & communicating with amba. That would be my best bet for finding anything useful for you.
 

zachnfine

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#78
What I'm really hoping for is to be able to set manual exposure and trigger a recording over a network connection. The ability to do manual exposure (shutter speed, aperture, and ISO) and manual white balance would be just great.
 

Andy_S

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#79
trigger a recording - thats what my app does.
anything fancier - well, that would be just guessing.
 

zachnfine

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#80
I wonder if it's possible to get a serial connection going, and if so get to the ambsh console prompt, and then run the kind of commands that would otherwise be in an autoexec.ash file? Might be a way to try a bunch of commands.

This looks interesting, as regards serial console access:
http://spritesmods.com/?art=zx3hack&page=3
 

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