Linux/AM5728: Video streaming from USB camera fails

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Hello,

I would recommend you to check the multimedia user guide for capture pipelines:
processors.wiki.ti.com/.../Processor_Training:_Multimedia
I would recommend you to set the format in the capsfilter(refer the guide).
Yo could try to add vpe element and set the capsfilter after it also.
If you try kmssink instead of waylandsink is it working(first stop weston)?
Hope this helps.

BR
Margarita

If you try kmssink instead of waylandsink is it working(first stop weston)?
Hope this helps.

i tried this but it giving same error.

$gst-launch-1.0 v4l2src device=/dev/video1 num-buffers=1000 io-mode=4 ! video/x-raw, format=YUY2, width=320, height=240 ! vpe num-input-buffers=8 ! queue ! kmssink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
[ 667.301303] contiguous chunk is too small 4096/153600 b
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data flow error.
Additional debug info:
../../../../gstreamer-1.8.3/libs/gst/base/gstbasesrc.c(2948): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming task paused, reason error (-5)
Execution ended after 0:00:01.270090268
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...
root@am57xx-evm:~#

also how to set capsfilter will you please help about how to set capsfilter??

thanks & regards

Vijay Patil

Hello,

For USB capture, please check this thread:
e2e.ti.com/.../2023362
You could add --gst-debug=v4l2src:5 for more debug prints.

BR
Margarita

I gone through the thread:
e2e.ti.com/.../2023362
------------------------------------------------------------------------------------------------------------------------------------
Root caused the issue to be with usb/uvc driver. The usb/uvc driver was using vmalloc to allocate the video buffers and hence large allocated buffers were not contiguous. VPE driver need contiguous buffers to work on and hence the handshake was failing. I modified the usb/uvc driver to work in dma-contiguous mode and with that change, below gstreamer pipeline works great. Attached patch of the changes done to usb/uvc driver.

gst-launch-1.0 v4l2src device=/dev/video1 num-buffers=1000 io-mode=4 ! 'video/x-raw, format=(string)YUY2, width=(int)1280, height=(int)720' ! queue ! vpe ! queue ! kmssink

usb_capture.txt

--------------------------------------------------------------------------------------------------------------------------------------

As mentioned, i have question,

how to change usb/uvc driver on AM5728-evm to work dma-contigeous mode and what is the process??
what changes i need to do on evm to open camera or video streaming??
Please tell the process.

Thanks & Regards.

Vijay Patil

Vijay,

You will need to apply the patch usb_capture.txt as shared in this e2e post to get the USB camera working. You may need to manually apply the patch as the kernel version may be different -

hi manisha,

i understand that i need to apply patch.

but where i apply the patch and how will i do this? will you tell the process.

it will helpful to me because i am new for am5728 sitara processor.

Thanks & Regards

Vijay Patil

Hello,

I would recommend you to apply the patch manually. As Manisha said the kernel version are different.
1. Open patch for example you see +....uvc_driver.c.
2.Open this file. In it you should add +#include <media/videobuf2-dma-contig.h> after #include <asm/unaligned.h>.
You should add these lines :
+ dev->alloc_ctx = vb2_dma_contig_init_ctx(&intf->dev);
+ intf->dev.coherent_dma_mask = DMA_BIT_MASK(32);
before /* Initialize controls. */
if (uvc_ctrl_init_device(dev) < 0)
and save the edited file.
Then open uvc_queue.c make the changes as you see it in the patch.
Same for other files.

Then you should recompile the patched source(kernel, modules etc) and cp them to the SD card.

I would recommend you to search over the internet for linux commands how patch could be apply.

Hope this helps.

BR
Margarita

Still it giving same error:

$gst-launch-1.0 v4l2src device="/dev/video0" ! video/x-raw , width=640, height=480 ! waylandsink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
[destroyed object]: error 0: invalid format 0x56595559

thanks and regard

Vijay Patil

Hello,

The pipeline that you are using seems not correct.
/dev/video0 does not seems right.
Please could you verify that this is the correct note for your camera (execute v4l2-ctl --list-devices).
I would recommend you to check this guide for capture pipelines:
processors.wiki.ti.com/.../Processor_Training:_Multimedia

BR
Margarita

its a mistake i entered the following command still it gives error:

$gst-launch-1.0 v4l2src device="/dev/video1" ! video/x-raw , width=640, height=480 ! waylandsink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
[destroyed object]: error 0: invalid format 0x56595559

thanks and regard

Vijay Patil

Hello,

Please refer the above link with capture pipelines.
Did you verify this is the correct device note?
This does not to be full console log. Verify the format, resolution in the caps filter is it correct.
You could add --gst-debug also for more debug prints.
I would recommend you to tr with yavta also. Here is the link:
processors.wiki.ti.com/.../Linux_Core_VIP_User's_Guide

Hope this helps.

BR
Margarita

Hello Vijay Patil,

I am closing this thread, please feel free to reopen it again.

BR
Margarita