Hello, On 7/10/19 4:33 AM, Hans Verkuil wrote: > On 7/10/19 12:19 AM, Helen Koike wrote: >> 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? > If you set up the pipeline like this: > > Video Output -> Scaler -> Video Capture If the capture will stall if there's no frame from the video output, how can I add support for this kind of pipeline at test-media? It would be required to send frames to the output device while running `v4l2-compliance` at the capture device to make testing possible. Thanks, André > Then this is a mem2mem device (except with two separate video devices) and > framerate doesn't apply anymore. And video capture will just stall if there > is no video output frame provided. > > It's how e.g. omap3isp works. > > Regards, > > Hans > >> 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 >>>
