Graphics, sound and multimedia • Re: TC358743 HDMI to HDMI Bridge

Hello,

i'm using a Pi5 with an TC358743 as a HDMI Bridge, i try to convert one HDMI format to another like 1080p to 720i or else.
I followed [this][viewtopic.php?p=2195617#p2195617] instructions to get the TC358743 working.

That thread is entitled "TC358743 HDMI to CSI-2 install instructions (Pi 0-4)", yet you say you're on Pi5.
Pi5 also doesn't have the H264 encoder, so the exact post you link to regarding v4l2h264enc is doubly irrelevant to Pi5.

So now to my problem:
if I use this:
src: 1080p@50hz
sink: 720p@60hz

I use gstreamer to do the job

Code:

gst-launch-1.0 v4l2src ! video/x-raw,width=1920,height=1080,format=RGB ! videoconvertscale ! capssetter caps="video/x-raw,width=1920,height=1080,format=BGR" ! kmssink sync=false

as long as I did not change the format the colors are corrected BGR->RGB shift
but if I changed the line to

Code:

gst-launch-1.0 v4l2src ! video/x-raw,width=1920,height=1080,format=RGB ! videoconvertscale ! capssetter caps="video/x-raw,width=1280,height=720,format=BGR" ! kmssink sync=false

I get the preferred resolution but the colorchange is gone.

Raspbian os is up to date

Code:

gst-launch-1.0 --versiongst-launch-1.0 version 1.22.0GStreamer 1.22.0https://tracker.debian.org/pkg/gstreamer1.0

videoconvertscale can do format conversion. By putting capssetter after videoconvertscale and not specifying what format it is you actually want on the output of videoconvertscale, it means that the negotiation can convert to BGR in videoconvertscale and therefore capssetter is doing nothing.

Put capssetter before videoconvertscale so that the format it is negotiating based on is correct, and then it should work.Note that the KMS driver can scale the video plane as part of the composition, so you shouldn't need to use the software videoconvertscale step.
In fact on my test system (it is running GStreamer 1.25) I can runand I get a 1080p test pattern rendered to what happens to be a 4k monitor for me.

Add "force-modesetting=true" to the end, and it will switch to a 1080p HDMI mode. Unfortunately it doesn't look like you can choose the mode to be used. There is an issue logged in GStreamer as https://gitlab.freedesktop.org/gstreame ... issues/776, but it hasn't been touched in the 6 years since it was created.

Statistics: Posted by 6by9 — Mon Jun 30, 2025 2:00 pm

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