Re: [PATCH v2 15/16] media: i2c: ov9282: Add support for 8bit readout

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Am Donnerstag, 3. November 2022, 10:53:49 CET schrieb Kieran Bingham:
> Quoting Alexander Stein (2022-11-03 08:49:48)
> 
> > Hi Kieran,
> > 
> > Am Dienstag, 1. November 2022, 21:37:09 CET schrieb Kieran Bingham:
> > > Hi Alex,
> > > 
> > > Quoting Dave Stevenson (2022-11-01 18:20:47)
> > > 
> > > > Hi Alexander
> > > > 
> > > > On Tue, 1 Nov 2022 at 15:04, Alexander Stein
> > > > 
> > > > <alexander.stein@ew.tq-group.com> wrote:
> > > > > Hi Dave,
> > > > > 
> > > > > thanks for the fast reply.
> > > > > 
> > > > > Am Dienstag, 1. November 2022, 14:47:16 CET schrieb Dave Stevenson:
> > > > > > Hi Alexander
> > > > > > 
> > > > > > On Tue, 1 Nov 2022 at 11:59, Alexander Stein
> > > 
> > > <snip>
> > > 
> > > > > > > Using this series I was able to do some camera playback on LVDS
> > > > > > > display on
> > > > > > > imx8mm based platform (TQMa8MxML). My command was
> > > > > > > 'gst-launch-1.0
> > > > > > > v4l2src
> > > > > > > device=/dev/video0 ! video/x-
> > > > > > > raw,format=GRAY8,bpp=8,width=1280,height=720,framerate=30/1 !
> > > > > > > videoconvert
> > > > > > > ! waylandsink'
> > > > > > > But due to SW colorspace conversion this is awfully slow.
> > > > > > > Using a testsink I get about 72FPS on 1280x720 for GREY. Is this
> > > > > > > to
> > > > > > > be
> > > > > > > expected?
> > > > > > > I used 'gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-
> > > > > > > raw,format=GRAY8,bpp=8,width=1280,height=720,framerate=30/1 !
> > > > > > > fpsdisplaysink video-sink="testsink" text-overlay=false
> > > > > > > silent=false
> > > > > > > sync=false -v' for that.
> > > > > > 
> > > > > > AFAIK v4l2src doesn't map from a caps framerate=30/1 to the
> > > > > > relevant
> > > > > > V4L2_CID_VBLANK and V4L2_CID_HBLANK controls used by raw sensors
> > > > > > for
> > > > > > frame rate control (see docs at [1]). The sensor will therefore
> > > > > > stream
> > > > > > at whatever rate the controls get left at.
> > > > > 
> > > > > Yes I noticed the framerate caps has no effect. But I lack some kind
> > > > > of
> > > > > reference system to decide what should work and what not.
> > > > 
> > > > As per the docs link, raw sensors will be using the HBLANK and VBLANK
> > > > controls, not VIDIOC_S_PARM.
> > > > I don't know whether the GStreamer folks wish to add support to
> > > > v4l2src to set those - libcamerasrc is going to be the more normal
> > > > user of these sensors, but that generally means needing an ISP of some
> > > > form. With just v4l2src you've got no AE / AGC control loops, so it is
> > > > only of use in controlled lighting conditions.
> > > > 
> > > > I don't know the full details of the imx8 range, but believe the
> > > > libcamera folk were working with one of the imx8 platforms.
> > > 
> > > We have the i.MX8MP working with the ISP available on that variant. I
> > > think we can also anticipate some support for other i.MX8 ranges with a
> > > GPU based 'ISP' in the (nearish) future, but I don't know what the
> > > timescales will be yet.
> > 
> > You are referring to (mainly) Paul Elder's patches to rkisp1, right? I
> > noticed them, but didn't get a chance for testing.
> 
> Yes, that's right - but you can only test those on an i.MX8MP not an
> i.MX8MM as I understand it.

Yes, i.MX8MM does not have an ISP. Let's see if I get the chance to try on 
i.MX8MP.

> > I noticed that using 'glupload ! glcolorconvert ! glcolorscale !
> > glcolorconvert ! gldownload' in a gstreamer Pipeline for converting
> > Y8/GREY to RGBA doesn't work, because mesa rejects creating appropriate
> > EGL buffers due to lack of some hardware features.
> 
> I haven't looked into the gstreamer EGL side of things I'm afraid.

No worries, I noticed that GPU on i.MX8MM, BTW the only one in i.MX8M series, 
does not support OpenGLES3 which might be the cause I'm stuck here. But I do 
not want to dig in that rabbit hole even further :)

Best regards
Alexander