Hi André, Thanks for the patches. On 7/2/19 12:47 PM, André Almeida wrote: > Hello, > > This patch adds a V4L2 output device on vimc, that comply with V4L2 API > for video output. If there is an output device and a capture device at the > same pipeline, one can get a video loopback pipeline feeding frames at > the output and then seeing them at the capture. It's possible to insert > vimc submodules at the pipeline to modify the image (e.g. a scaler). > > If one starts a streaming at the capture, with the output off, the > capture will display a noisy frame. If one starts a streaming at the > output with the capture off, the output will just consume the buffers, > without sending them to the pipeline. If both output and capture are > streaming, the loopback will happen. I understand why it is done like this in vivid, but I was wondering, if we have a pipeline like: output -> capture Shouldn't streaming from the capture just stalls if there is no frame available in the output (i.e. streaming in the output is off) ? But then I'm not sure what the framerate in the capture would mean. Hans, what do you think? Thanks, Helen > > The patches 1 and 2 provide some ground to create the output > device. The patch 3 creates the device and modify how the vimc-streamer > was dealing with the s_stream callback on other vimc modules, to make > simpler implementing this callback at vimc-output. Patch 4 change the > behavior of the pipeline in order to be closer to a real life hardware. > Patches 5-7 updates the default pipeline and the documentation to > include the new output device. > > This is the result of v4l2-compliance after this patch series: > $ v4l2-compliance -m0 -s50 > Grand Total for vimc device /dev/media0: 476, Succeeded: 476, Failed: 0, > Warnings: 0 > > A git tree up to date with media-master and with this changes can be found > at: https://gitlab.collabora.com/tonyk/linux/tree/vimc/output > > In order to test it, one can follow these instructions: > > 1 - Configure the pipeline (requires v4l-utils): > > $ media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]' > $ media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]' > $ media-ctl -d platform:vimc -V '"Sensor B":0[fmt:SBGGR8_1X8/640x480]' > $ media-ctl -d platform:vimc -V '"Debayer B":0[fmt:SBGGR8_1X8/640x480]' > $ v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440 > $ v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81 > $ v4l2-ctl -z platform:vimc -d "Raw Capture 1" -v pixelformat=BA81 > $ v4l2-ctl -z platform:vimc -e "RGB/YUV Input" -v width=640,height=480 > > 2 - Use a userspace application: > 2.a gst-launch (requires gstreamer and gst-plugins-good): > > Feed frames into the output and grab from the capture (rescaled for > convenience): > > $ gst-launch-1.0 videotestsrc pattern=ball ! \ > video/x-raw,width=640,height=480,format=RGB \ > ! v4l2sink device=/dev/video2 v4l2src device=/dev/video3 ! \ > video/x-raw,width=1920,height=1440,format=RGB ! videoscale ! \ > video/x-raw,width=640,height=480 ! videoconvert ! ximagesink > > 2.b qv4l2 (requires v4l-utils): > > Open the output device: > > $ qv4l2 -d2 > > Open the capture device: > > $ qv4l2 -d3 > > Start the streaming at both, at any order. You can change the frame > content at "Test Pattern Generator" -> "Test Pattern" on the output. > > Thanks, > André > > André Almeida (7): > media: vimc: Create video module > media: vimc: video: Add write file operation > media: vimc: Create a V4L2 output device > media: vimc: Send null buffer through the pipeline > media: vimc: core: Add output device on the pipeline > media: vimc.dot: Update default topology diagram > media: vimc.rst: Add output device > > Documentation/media/v4l-drivers/vimc.dot | 4 +- > Documentation/media/v4l-drivers/vimc.rst | 12 +- > drivers/media/platform/vimc/Makefile | 4 +- > drivers/media/platform/vimc/vimc-capture.c | 356 +++---------------- > drivers/media/platform/vimc/vimc-common.h | 5 +- > drivers/media/platform/vimc/vimc-core.c | 7 +- > drivers/media/platform/vimc/vimc-debayer.c | 14 +- > drivers/media/platform/vimc/vimc-output.c | 362 ++++++++++++++++++++ > drivers/media/platform/vimc/vimc-scaler.c | 13 +- > drivers/media/platform/vimc/vimc-sensor.c | 10 +- > drivers/media/platform/vimc/vimc-streamer.c | 24 +- > drivers/media/platform/vimc/vimc-video.c | 273 +++++++++++++++ > drivers/media/platform/vimc/vimc-video.h | 130 +++++++ > 13 files changed, 849 insertions(+), 365 deletions(-) > create mode 100644 drivers/media/platform/vimc/vimc-output.c > create mode 100644 drivers/media/platform/vimc/vimc-video.c > create mode 100644 drivers/media/platform/vimc/vimc-video.h >
