Raw image quality and bandwidth

[diegomrt]

Hi,

I'm getting an unusable image from the /tello/image_raw topic, it is 90% filled with green pixels. My laptop and the Tello drone are 50 cm away, and the WiFi link quality is perfect (70/70) with a Bit Rate of 54 Mb/s (this is the top value I get).

I guess the problem comes from the /tello/image_raw topic bandwith, that is around 62 MB/s (30 FPS). Is there any way of decreasing it?

I'm attaching a screenshot with the driver parameters and the image quality I get. Changing stream_h264_video to true or playing with the image quality parameter doesn't solve the problem.

Thanks in advance.

[craigcraigcraig]

+1 I'm seeing the same behavior. The video displayed in image_view is very slow, best way to describe is that it looks like it's moving in slow motion (in addition to the green noise).

[zhangk23]

I'm seeing similar problem except the noise is background color not green. Any idea how to resolve? Thanks a lot!

[diegomrt]

Is there any update? This issue was posted more than 2 months ago.

[anqixu]

This seems to be due to out-of-order UDP packets, and how the original TelloPy driver handles them. It might also be caused by dropped packets, but doesn't seem to be an issue in your case. See if this improves things:

https://github.com/anqixu/TelloPy/commit/6044cfe36f0c3c088af728637107dbf1ecffa5f8

P.S.: sorry for the tardy response. This is a hobby side-project, so it's hard for me to find time to work outside of my full-time employment.

[anqixu]

Oh and yes, you can decrease the video bitrate here:

https://github.com/anqixu/TelloPy/blob/develop-0.6.0/tellopy/_internal/tello.py#L288

I haven't figured out what the equivalent bitrates are, but pass a value of 1 for the lowest bitrate. values 6+ (or 0) seems to be the max bitrate, and it increases linearly in-between.