[RFC PATCH 0/1] Enable raw streams with software ISP

[Robert Mader]

Hi, thanks for the patch!

I gave this a quick try with Millipixels 
(https://source.puri.sm/Librem5/millipixels) which uses raw streams. It 
looks like the app will need manual adjustments to work with this patch 
- but that's kinda expected IIUC (Millipixels apparently doesn't request 
raw streams explicitly yet). It looks like other API changes on master / 
in 0.4 will require manual changes to the app anyway, so that shouldn't 
be a big deal.

Do I understand correctly that exposure and gain were never supported 
for raw streams yet? Because in that case the patch here *is* already 
useful for Millipixels at it would allow it to co-exist with apps 
requiring swISP without requiring hacks like this: 
https://gitlab.postmarketos.org/postmarketOS/pmaports/-/blob/master/temp/libcamera/0002-libcamera-simple-Force-disable-softwareISP-for-milli.patch

In other words: even without gain/exposure I'd be happy to have this in 
0.4, especially if that allows us to enable the swISP on all platforms 
by default.

On 22.11.24 21:13, Milan Zamazal wrote:
> This makes raw streams working again in ‘simple’ pipeline when software
> ISP is enabled for the given device.  For now, only a single raw stream
> is supported and there are no immediate plans to change that unless
> there is a request for more.
>
> An example ‘cam’ invocation requesting a raw stream rather than a debayered stream:
>
>    cam -c1 -C8 -s role=raw,width=1920,height=1080 -Ffile#.raw
>
> See the commit message for more information about the patch.
>
> The patch is RFC because I’m not sure where it is placed on the scale
> between a hack/PoC and a proper solution and because it’s not that
> useful until a control for exposure/gain adjustments is implemented.
>
> In the meantime, fixed exposure+gain can be hardwired in
> src/ipa/simple/soft_simple.cpp by changing the lines
>
>    ctrls.set(V4L2_CID_EXPOSURE, …);
>    ctrls.set(V4L2_CID_ANALOGUE_GAIN, …);
>
> to set the desired values (values used under the given conditions can be
> obtained from normal software ISP debayered output debug log).
>
> Milan Zamazal (1):
>    libcamera: simple: Fix raw output
>
>   src/libcamera/pipeline/simple/simple.cpp | 66 +++++++++++++++++++-----
>   1 file changed, 54 insertions(+), 12 deletions(-)
>