[00:39] <shibboleth> bttv-related question: i've noticed /dev/videoN and /dev/vbiN
[00:39] <shibboleth> please correct me if i'm wrong: will the vbi device mirror what's being captured from the sister video device?
[00:49] <shibboleth> also: anyone own(ed) a LMLBT4/card=118 and have any advice re stability?
[01:55] <HZun> Is V4L2 used on "modern systems"? I thought everything modern was digital and not analog. Is it just a legacy API?
[02:14] <pinchartl> HZun: V4L2 is not analog only
[02:15] <pinchartl> it handles USB webcams, digital TV capture cards, embedded cameras, video codecs, ...
[02:20] <HZun> hmm ok. I just find it confusing that https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/dev-capture.html states "Video capture devices sample an analog video signal", and other places in the documentation i kinda got the impression that v4l2 was analog-only.
[02:21] <HZun> something went wrong with that output.
[02:21] <pinchartl> some parts of the documentation are very old
[02:21] <pinchartl> and haven't been updated for a while
[02:22] <HZun> ok. good to know :)
[02:22] <pinchartl> are you considering using V4L2 for any particular project ?
[02:23] <HZun> not for a particular project. just wanted to learn a little bit about it in order to see how it compares to drm/kms.
[02:24] <HZun> since v4l2 also have an output API.
[02:24] <pinchartl> it has a much broader scope :-)
[02:24] <pinchartl> the output API competes a bit with DRM/KMS
[02:25] <pinchartl> it predates it
[02:25] <pinchartl> nowadays the V4L2 output API is mostly used for memory to memory devices (such as video codecs) to handle the interface from memory to the hardware
[02:26] <pinchartl> we still support the output API to a display connector, but no new driver have implemented that for quite some time as far as I know
[02:27] <HZun> what is "new" here? 1 year? 10 years?
[02:34] <HZun> like just approximately.
[02:34] <HZun> or have you heard of any non-vga output drivers? (such as DVI/HDMI/DP TMDS).
[02:37] <pinchartl> I would say about 10 years, yes
[02:37] <pinchartl> drivers/media/platform/omap/ supports DVI and HDMI output
[02:40] <HZun> ok. you said it is mostly being used for m2m devices. Is some newer other API being used for input devices (such as cameras)?
[02:41] <HZun> and how does v4l2 encoding/decoding compare to stuff like VA-API/VDPAU/NVDEC (if you know of those). like why would i use v4l2 and not those other APIs?
[02:45] <pinchartl> those codec APIs are userspace APIs
[02:45] <pinchartl> I believe there are VA-API implementations on top of V4L2 codec drivers
[02:45] <pinchartl> (but I'm not a codec expert)
[02:45] <pinchartl> as for newer APIs for cameras, not really
[02:46] <pinchartl> we're considering options to move forward though, as embedded cameras increasingly have needs that are not completely fullfilled by V4L2
[02:46] <pinchartl> but V4L2 evolves constantly with new features
[02:49] <HZun> ok. thanks a lot for the help. one last question. can you recommend a well-supported device to purchase if a want to play around with some v4l2 code.? or is there a list of well-supported devices somewhere?
[02:50] <pinchartl> for capture, output, or codecs ?
[02:52] <HZun> preferable something that can do it all, if it exist. since it is just to get a feel for the API by trying to use it on a small toy project.
[02:52] <pinchartl> I don't think that exists :-)
[02:52] <pinchartl> I would recommend getting a USB webcam
[02:53] <pinchartl> pretty much any USB webcam is compatible with UVC today, and supported by the uvcvideo driver
[02:53] <pinchartl> the webcam integrated in your laptop (if any) likely works with that driver
[02:53] <pinchartl> otherwise you don't even need hardware
[02:53] <pinchartl> you can use the vivid driver
[02:53] <pinchartl> it creates virtual V4L2 capture and output devices
[02:53] <pinchartl> so you can play with them from userspace without needing actual hardware
[02:54] <HZun> seems perfect for what i need :) I'll check it out.
[02:54] <HZun> thanks for the help :)
[02:56] <pinchartl> you're welcoem
[12:34] <kamel_b> Hello, Im getting stuck using kernel 5.4 + imx-media, I don't have /dev/media0 showing, it seems the issue comes from the video-mux not being able to probe the mux chip, any clue about it ?
[14:50] <ndufresne> pinchartl: you could have proposed vivid, vimc, vim2m, they do everything for toying purpose
[14:53] <pinchartl> ndufresne: it was late I didn't want to start explaining vimc :-)
[14:53] <ndufresne> understandable
[16:44] <jernej> paulk-leonov: Can you please check https://patchwork.linuxtv.org/cover/60729/ ?
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[19:29] <shibboleth> i've recently inherited the responsibility for some systems that involve bttv capture cards. anyone present who wouldn't mind me picking their brain/institutional knowledge?
[23:29] *** cazzacarna has left