Yi 4k custom bitrate mod and telnet.

hirsti99

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Thanks very much for this, I've tried it out myself and can't get past 90 Mbps, but I only have a class 10 card. There is a difference between the standard 60 and the increased 90. Nice Work.
 

valdi99

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Great job, irugentoo, it works like a charm! On factory bitrates image quality was rather crap...
 

Ar1

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Thank you irungentoo for sharing your work. I have tried the bitrate mod up to 120Mbps (closer to 116Mbps according to mediainfo). I'm using a Sandisk Extreme U3 V30 64GB (http://a.co/eBJ7kKy). I tried recording for about 15 minutes and had no issues. Maybe the camera got a little bit hot, but not sure it was hotter than usual (need to do a bit more testing).

I also tried the 4700x2000 recording for the 4K ultra 24 fps (I prefer 24 fps when possible). I can now crop to 16:9 with more vertical room for better composition and have more of the image after applying lens correction. The only downside to 4700x2000 is that the recorded clips can't be played in the camera.

I have a few questions:

- do you have the addresses for modifying the captured resolution for other modes? I'm interested in the 1080p ultra 120 fps. It should be possible to do 2000x1350 in that mode. Have you tried it?

- Also is it possible to change the 30 fps of existing modes to default to 24 fps instead?

Thank you again for your awesome work!
 
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irungentoo

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I have the addresses to change the output resolutions and output framerates for all the modes. On their own they are pretty useless though, the only real use is to change the output resolutions to better match the input resolution (in the case of the 4k ultra mode the input resolution seems to be 4000x3000 but setting the output resolution to something above 4000x2700 like 4000x2800 crashes the camera).

This should set the 1080 90p ultra mode to 2000x1500, tell me if it works, if it's stable I'll put in on my github:

#set 1080p ultra 90p to 2000x1500
writel 0xA0621B4C 0x05DC07D0


Right now I can only change the output framerate, not the input framerate. If the output framerate is lowered it crashes the camera, if the output framerate is raised it just makes the video playback at a higher framerate.
 

Mighty777

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Is it possible to set 4K mode (NOT the Ultra) to 4000x2700 at 25fps? That would be awesome in post-production when correcting for less distortion (which usually crops a lot of visible area....)
 
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irungentoo

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It's probably possible to increase the framerate of the 4k ultra resolution to 25 if I can figure out how to change the input modes. I can increase the output resolution of the normal 4k mode but it just upscales the 3840x2160 source image to what I put.
 

Mighty777

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It's probably possible to increase the framerate of the 4k ultra resolution to 25 if I can figure out how to change the input modes. I can increase the output resolution of the normal 4k mode but it just upscales the 3840x2160 source image to what I put.

Thanks for trying. It is a pity...the 4000x3000 resolution (which is available in the Yi 4k+) would have helped when correcting for lens distortion, but having that resolution (or close to) available only in the Ultra mode (which, for my taste, it is with a far too wide FOV, for anything else than extreme sport...) is not that helpful to me :-(
Congrats for your effort, much appreciated (the bitrate hack is awesome!)
 

hirsti99

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Hi irungentoo, Yi have released a new firmware version 1.4.14 which is available on their support site.
The bitrate hack no longer works, I suspect the memory addresses have changed.
 

hirsti99

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Yes I have tried it and all the new features.

Here is the changelog:
 

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Pablo Guerrero

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Do you have the chinese or the US version? The EN_US and ES_Es download seems to download the chinese one.
 

hirsti99

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I downloaded the EN_US one and it installed ok
 

Pablo Guerrero

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Thanks, it's the same I've downloaded. But opening it with an hex editor I've seen the last bytes says zh-cn instead of en-us, so I was worried. Maybe now it's the same firmware for all camera versions.
 

Mighty777

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...from the changelog it does not seem worth upgrading...especially until somebody has found a way to restore the bitrate hack on this new firmware...I have now got used to the 4K at 120fps.....
 
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irungentoo

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Bitrate and other mods are updated to firmware 1.4.14, let me know if something broke.
 

hirsti99

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Thank You irungentoo, that works brilliantly :D
 

Ar1

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Thank you!!! BTW, I have settled for 3840x2880 in 4K ultra 24 fps ("writel 0xA0637AD4 0x0B400F00"), instead of 4000x2700, 3840x2880 has proper 4:3 aspect ratio so it is easier to do lens correction and it still has some additional vertical resolution for cropping/panning during editing. I can also mix with 1080p 120 fps when needing slow motion (5x in 24 fps) and render all in 24 fps without stutter. One interesting observation, using 120 Mbps, the frame bitrate per mega pixel is about the same for 4K30, 4K24 and 1080p120 (120 Mbps / (resolution_in_MP * frame_rate)):

4K30: 0.48 Mbps / MP
4K24 (3840x2880): 0.45 Mbps / MP
1080p120: 0.48 Mbps / MP

The quality of a captured frame cropped from 3840x2880 (4k24 4:3 mod) to 3840x2160 is virtually the same as the 4K30 frame which is confirmed by my tests.
 

Mighty777

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c
Thank you!!! BTW, I have settled for 3840x2880 in 4K ultra 24 fps ("writel 0xA0637AD4 0x0B400F00"), instead of 4000x2700, 3840x2880 has proper 4:3 aspect ratio so it is easier to do lens correction and it still has some additional vertical resolution for cropping/panning during editing. I can also mix with 1080p 120 fps when needing slow motion (5x in 24 fps) and render all in 24 fps without stutter. One interesting observation, using 120 Mbps, the frame bitrate per mega pixel is about the same for 4K30, 4K24 and 1080p120 (120 Mbps / (resolution_in_MP * frame_rate)):

4K30: 0.48 Mbps / MP
4K24 (3840x2880): 0.45 Mbps / MP
1080p120: 0.48 Mbps / MP

The quality of a captured frame cropped from 3840x2880 (4k24 4:3 mod) to 3840x2160 is virtually the same as the 4K30 frame which is confirmed by my tests.

Cool. Any solution to set such expanded resolution in the normal 4K mode (i.e. with the Wide FOV and not with the UltraWide FOV, as happens in the 4K Ultra mode?
 
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