Incorrect colours on Raspberry Pi 4, -avdec is faster than hardware decoding

[connorh315]

Receiver device running UxPlay: Raspberry Pi 4
Sender: iPad Pro (M1) | iPhone 15 Pro
OS Version: Most recent Raspberry Pi OS (64-bit) with Desktop - "Debian GNU/Linux 12 (bookworm)" - released 2024-07-04
GStreamer version - 1.22.0
UxPlay version: 1.69
Launch command: ./uxplay -p -d
Videosink: any

My Raspberry Pi 4 is not showing certain colours from the Airplay stream. It is the exact same as the issue described here: #313. The only difference is that I know it cannot be the sender device not sending the correct colours as the stream looks perfect on my Windows machine running UxPlay. As such I can only assume that it is a Linux GStreamer issue. I have tried xvimagesink, ximagesink and glimagesink and they don't make a difference. Just as some additional information, -avdec produces a smoother stream than hardware decoding on all the videosinks which is odd. I have reinstalled the Raspberry Pi OS twice now to check and used on two different Raspberry Pi 4 boards

This is not an issue with the sender device sending poor streams, as my UxPlay instance running on Windows does not have the same colour issues.

[fduncanh]

I see it.

seems OK on linux, but the red seems brown and the blue is less bright on r pi.

https://www.youtube.com/watch?v=lnrJASmgHBM

[connorh315]

There seems to be a big issue with greys as well, some greys just do not show up at all and instead are rendered as white only. I'll try and grab a screenshot in a bit.

[fduncanh]

I compared the above image on R Pi with (side by side) (1) the image shown on firefox on R Pi.
(2) the image on uxplay on R Pi, transmitted from the screen if an iPad showing it.

on RPi firefox and UxPlay seem to have identical colors so it seems to be a R Pi issue, not UxPlay ?
please do this test for yourself and report what you see.

[fduncanh]

please find a link to a greyscale image on web, that the viewing-side-by-side-on-browser-and-uxplay test can be done on.

[fduncanh]

is this a fix?

https://forums.raspberrypi.com/viewtopic.php?t=304842

EDIT: I did this but am not sure if it changes anything?

[connorh315]

I tried that one already and I don't think it made any improvements either :(

[fduncanh]

In any case since uxplay and firefox show identical colors (do you agree?) , its not a uxplay or gstreamer problem.

There should be a fix to be found out there on the web?

[connorh315]

Definitely, will close this - Once I've found a solution I'll post it here.

[connorh315]

Sorry, might've prematurely closed this, please see attached image; It shows a screenshot of the iPad screen, compared against the actual UxPlay stream:

--Photo removed--

You can see the difference is mainly with greys being off, or just converted to white?

[connorh315]

Attached here is the UxPlay stream as seen from a Windows PC, showing that the correct colours are being sent by the sender:

--Photo removed--

[fduncanh]

I see the grey issue. so that is uxplay/gstreamer.

what about the color issue?

[connorh315]

Sorry I hope that I didn't come across like it was a vibrant colour issue, I meant that the grey "colour" was showing up as white. I probably should've put a reference image there 😬