Gstreamer strange issue with multiple video sources

Technical Support
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1

Hello

We are experiencing a strange issue with gstreamer 1.0: We have a custom board where is plugged the Apalis imx6Q. On this custom board, we have 2 video sources capabilities: one HD-SDI input (gs1661) and one analog input (adv7280).

After flashing the whole images (run update from uboot) on the apalis with the device tree reflecting these 2 video inputs, we can’t launch a gstreamer capture on any of our video source: the message *(gst-plugin-scanner:634): GStreamer-CRITICAL *: passed ‘0’ as denominator for `GstFraction’ is looping. Even if we launch gst-inspect this message is looping!

The workaround is to reboot with a device tree with only one video source (video source choices no matters). Then we can launch correctly a video capture. Then we boot again with the device tree with the 2 video source and everything work fine: we can capture the 2 video sources

2

hi @axel

Could you provide the version of the hardware and software of your module?

the message (gst-plugin-scanner:634): GStreamer-CRITICAL : passed ‘0’ as denominator for `GstFraction’ is looping. Even if we launch gst-inspect this message is looping!

Which commands did you use exactly?

The workaround is to reboot with a device tree with only one video source (video source choices no matters). Then we can launch correctly a video capture. Then we boot again with the device tree with the 2 video source and everything work fine: we can capture the 2 video sources

Did you do a soft reboot or powercycle?
Can you share a dmesg log when doing power cycle and soft reboot?

Best regards, Jaski

3

hello jaski

Our module is the Apalis imx6Q 2GB IT V1.1B

We build our software based on angstrom-lxde-image. The issue is observed on both 2.7b4 and the last release 2.8b5

The issue occurs after flashing our whole image with a device tree describing our 2 video source capabilities:

 v4l2_cap_0 { //adv7280
        compatible = "fsl,imx6q-v4l2-capture";
        ipu_id = <0>;
        csi_id = <0>;
        mclk_source = <0>;
        status = "okay";
    };
    v4l2_cap_1 { // gs1661a
        compatible = "fsl,imx6q-v4l2-capture";
        ipu_id = <1>;
        csi_id = <1>;
        mclk_source = <0>;
        status = "okay";
    };

In this case, we can’t launch any gstreamer commands, even commands which do not involved our video inputs. For example we can’t display a picture:
gst-launch-1.0 filesrc location=/home/root/NoHDSDI.jpg ! jpegdec ! imagefreeze ! imxg2dvideosink -e
And as I said we can’t even launch gst-inspect

The only workaround we found at this time is to build a new device tree with only one video source described (no matter which one)

v4l2_cap_0 { //adv7280
        compatible = "fsl,imx6q-v4l2-capture";
        ipu_id = <0>;
        csi_id = <0>; 
        mclk_source = <0>;
        status = "disabled";
    };
    v4l2_cap_1 { // gs1661a
        compatible = "fsl,imx6q-v4l2-capture";
        ipu_id = <1>;
        csi_id = <1>;
        mclk_source = <0>;
        status = "okay";
    };

This new dtb is directly paste into embedded flash (/media/mmcblk0p1/) from linux.

We reboot with Linux reboot command (no hard reboot) and then gstreamer works fine.

We paste then the original dtb with our 2 video inputs and after a Linux reboot gstreamer works fine

The dmesg log before workaround and after shows only that one input source is missing

4

This is very strange. Could you provide the changes to the devicetree files and the dmesg log?

What is the output of v4l2-ctl --list-devices?
And what is the output of v4l2-ctl -d /dev/video* where for * you put the number which got from the list devices command?