Re: [PATCH 1/4] media: imx.rst: Fix the MIPI CSI-2 virtual channel

[Steve Longerbeam <slongerbeam@gmail.com>]

On 4/8/20 12:28 PM, Fabio Estevam wrote:
> Hi Steve,
>
> On Wed, Apr 8, 2020 at 4:16 PM Steve Longerbeam <slongerbeam@gmail.com> wrote:
>
>> You have to set a format at the capture interface as the last step
>> before streaming can start:
>>
>> # v4l2-ctl -d /dev/video1 --set-fmt-video=pixelformat=RGB3
> Thanks. After running this line the stream can start via --stream-mmap:
>
> # v4l2-ctl --stream-mmap -d /dev/video1
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 30.03 fps
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 30.03 fps
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 30.03 fps
>
> but it fails with Gstreamer:
>
> # gst-launch-1.0 -v v4l2src device=/dev/video1 ! kmssink
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> /GstPipeline:pipeline0/GstKMSSink:kmssink0: display-width = 1024
> /GstPipeline:pipeline0/GstKMSSink:kmssink0: display-height = 768
> ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
> Internal data stream error.
> Additional debug info:
> ../libs/gst/base/gstbasesrc.c(3072): gst_base_src_loop ():
> /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
> streaming stopped, reason not-negotiated (-4)
> ERROR: pipeline doesn't want to preroll.
> Setting pipeline to PAUSED ...
> Setting pipeline to READY ...
> Setting pipeline to NULL ...
> Freeing pipeline ...
>
> Should I change the Gstreamer pipeline?

It works for me, I'm running gstreamer version:

arm:~/scripts % gst-launch-1.0 --version
gst-launch-1.0 version 1.14.5
GStreamer 1.14.5
https://launchpad.net/distros/ubuntu/+source/gstreamer1.0

Also, I'm streaming to an HDMI monitor at 1920x1080 (passing 
connector-id=54 to kmssink).

I can't tell from your gst output whether you are having an issue with 
pixelformats or frame dimensions, but anyway here is my gst pipeline:

gst-launch-1.0 v4l2src device=/dev/video1 ! kmssink connector-id=54 
name=imx-drm sync=0 can-scale=false

It might also be the can-scale property, you might need to provide 
can-scale=false to tell kmssink that imx-drm cannot scale 800x600 to 
something else.

While streaming, I checked what pixelformat the pipeline finally settled on:

arm:~/scripts % v4l2-ctl -d1 -V
Format Video Capture:
     Width/Height      : 800/600
     Pixel Format      : 'XR24'
     Field             : None
     Bytes per Line    : 3200
     Size Image        : 1920000
     Colorspace        : sRGB
     Transfer Function : sRGB
     YCbCr/HSV Encoding: ITU-R 601
     Quantization      : Full Range
     Flags             :

Steve