On 7/12/19 5:38 PM, André Almeida wrote: > 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. The compliance test doesn't support such devices at the moment. I think a new option (or options) are needed to tell the compliance test that the capture and output video devices together constitute an m2m device. Regards, Hans > > 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 >>>>
