Hello. I am new here - testing to see if I can send a message
Seemed to work :-)  Is it ok to ask end-user questions regarding v4l2-ctl here?
rus190: I think so, of course most of the chat here is about development, just ask
Ok, thanks. I am attempting to rotate my webcam feed, but "rotate" and vertical_flip are not present in the list of controls for my webcam in v4l2-ctl. The webcam is a Logitech Brio. I have a number of other Logitech webcams, and none of them have this control available. I assume that is a limitation of the webcam that I can do nothing about. Is that true?
I think it's pretty rare that cams offer a flip function
rus190: but for badly mounted cams (e.g. cams mounted up-side-down on laptops) there is some quirks possible in uvc driver
I am able to flip using guvcview but the change only applies while using that app, it does not affect other apps - for my use-case, Google Meet
UVC is copying the frame to reconstruct the image from variable chunk, so it can do vertial flip while at it
but now I'm speaking over my hat, I don't know what is really being done
pinchartl would know, but he might be too busy or asleep
Sure thing. Thank you. I will ask again during his waking hours. I'm on the other side of the earth :-)
For me this is Australia
I'm in New Zealand
close by, actually I should check the globe again, perhaps New Zeland is more proper other side of the world
so it's thurday for you already ?
Yep, let me know if you would like to know what happens tomorrow!
lol
the uvcvideo driver doesn't process frames in software
so if the camera doesn't expose h/v flips, rotation won't be possible
lots of cameras could actually support doing so, but expose it through an extension unit
and those are undocumented
Ok, thanks. Is there a different approach you could recommend?
it's an external camera, right ?
Yes
As mentioned above, I can flip in guvcview, but the change doesn't apply to other apps using the webcam.
Interestingly, the wikipedia article for guvcview says:
Through the Linux UVC driver, Guvcview offers extension controls, vendor-specific controls included in the UVC specifications, which are dynamically loaded into the driver. At present only webcam-maker Logitech has provided the specifications for their UVC webcam extension controls and as a result Logitech camera extension controls are included.
it may be that the webcam exposes that then
pinchartl: well, you do process as you memcpy that data, and while doing it, if you switch to a line-by-line copy approach, you can implement vflip without any new overhead
(we also need line by line copy to support import of padded buffers, e.g. with non-standard stride)
ndufresne: URBs are not line-aligned, it would add quite a bit of complexity
probably doable
but vflip alone isn't great without hflip
rus190: there's a tool call uvcdynctrl that can add mappings between extension units and V4L2 controls to the driver
after that, h/v flip would be available as V4L2 controls
and this gives me a great idea
who wants to submit a patch to libcamera to support XU controls ? :-)
pinchartl: I see uvcdynctrl has the --addctrl=vid option. Any idea what vid is there?
I notice that when I turn v_flip on and off, the config file for guvcview (~/.config/guvcview2/video0) changes the "video_fx" config line from "0x2" to "0x0". That is probably a guvcview-specific config value though
rus190: it's getting too late for me I'm afraid, I need to go
if you're around tomorrow we can continue the discussion
otherwise, could you drop me an e-mail and CC the linux-media mailing list ?
What is a good time for you tomorrow, and what timezone?
I'm in UTC+2
I think e-mail may be easier
ok
paulk-leonov: what is the status of v5 "Allwinner MIPI CSI-2 support for A31/V3s/A83T"? Is it waiting for more acks? Can the phy patches be merged through the media subsystem or is an ack from the phy subsystem maintainer needed (whoever that is)?
hverkuil: thanks for the PR!
I think Mauro did some important fixes to the rst documents, and so perhaps you'd like me to rebase on top of that?
and we could address gnurou comment about the "seg" -> "segment" field name, which could make sense (no strong opinions here).
ezequielg: if you want a respin, then that's fine by me. I do prefer segment over seg, I missed that change.
yeah, it makes sense. Guess I was too aggressive there.
I'll reject the PR and wait for a rebased version. (not sure which rst fixes you are referring to, though).
"media: docs: uAPI: fix table output in LaTeX/PDF format"
hverkuil: I'll send a new series based on master, if that works.
which master? media_tree master?
ezequielg: media_tree master works.
cool.
ezequielg: do you think you can post a new series today?
I'm working on it.
Just checking that the changes are taking into account Mauro's rst changes.
hverkuil: sent!
ezequielg: posted PR
coolio.
fyi, VP9 work is progressing very nicely.
from Adrian, right?
ezequielg: last vp9 patches I see were from November last year, correct?
yes, last one is very old, we have a new team taking care now, which you may know as he worked with mchehab on DVB virtual driver, and Andrzej are working on it
Daniele and Andrezej, sorry wasn't clear
good to know that Daniel is joining the efforts ;-)
(:
Ah, Collabora picked up yet another media volunteer :-)  This seems to be a fruitful subsystem for new employees!
that's the goal ! more folks involved, more knowledge
(it's also admittedly overwhelming work)
robertfoss: ping
robertfoss_: ping
robertfoss: robertfoss_: what is the status of "[PATCH v6 00/22] Add support for the SDM845 Camera Subsystem"? It looks like the sdm660 clock driver it depends on has been accepted for 5.13. Is anything blocking merging this series for 5.13 in the media tree?
hverkuil: i think one patch in v6 lacks an r-b, and saw big changes in v6
robertfoss: OK, then I'll wait for that. Just ping me when you think it is ready to be merged.
I looked over the series quickly and it looked OK to me, but a lot of it is low-level SoC code, so due to lack of knowledge of the SoC I just have to assume that you know what you are doing :-)
hverkuil: ack.
yeah, it's pretty hard to wrap your head around even with the documentation :p