[PATCH v3 0/8] Enable raw streams with software ISP

[Milan Zamazal]

This makes raw streams working again in ‘simple’ pipeline when software
ISP is enabled for the given device.  At most one raw stream and one
processed stream (possibly both at once) are supported.

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

Or for both raw and processed streams:

  cam -c1 -C8 -Ffile# \
    -s role=viewfinder,width=1920,height=1080,pixelformat=RGB888 \
    -s role=raw,width=3280,height=2464,pixelformat=SRGGB8 \

When only a raw stream is requested, there are no exposure/gain
adjustments applied.  This could be improved in future, once software
ISP gets a mechanism to gather image statistics without processing and
using them to make the adjustments, or once manual exposure controls are
added to software ISP.  In the meantime, exposure must be changed
externally.

Changes in v3:
- Significantly reworked, with both functional and clarity improvements.
  The level of guesswork and confusion is hopefully reduced enough now
  to drop the RFC prefix.
- The number of streams is set to 2 only with software ISP.
- SimpleCameraData::pipeConfig_ nullptr check patch dropped.
- PPM/raw file output patch dropped from this series.  Let’s handle this
  separately as the patch series is already complex enough.

Changes in v2:
- Completely reworked.
- Extended to be able to produce a raw stream together with a processed
  stream.

Milan Zamazal (8):
  libcamera: simple: Set the number of software ISP streams to 2
  libcamera: simple: Don't use raw output formats with conversions
  libcamera: simple: Add plain output configurations
  libcamera: simple: Identify requested stream roles
  libcamera: simple: Consider raw output configurations
  libcamera: simple: Validate raw stream configurations
  libcamera: simple: Don't enforce conversion with an added raw stream
  libcamera: simple: Make raw streams working

 src/libcamera/pipeline/simple/simple.cpp | 231 +++++++++++++++++------
 1 file changed, 173 insertions(+), 58 deletions(-)

-- 
2.48.1