Link nvosd to nvv4l2h264enc

Accelerated Computing Intelligent Video Analytics DeepStream SDK
1

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU)
• DeepStream Version
6.2
• JetPack Version (valid for Jetson only)
• TensorRT Version
• NVIDIA GPU Driver Version (valid for GPU only)
• Issue Type( questions, new requirements, bugs)
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)

I want to connect the nvdosd to nvv4l2h264enc , but shows and error

Elements could not be linked. Exiting.

I have checked the sink and src ok nvv4l2h264enc and nvosd using gst-inspect.
It shows the src of the nvosd is

SRC template: ‘src’
Availability: Always
Capabilities:
video/x-raw(memory:NVMM)
format: { (string)NV12, (string)RGBA }
width: [ 1, 2147483647 ]
height: [ 1, 2147483647 ]
framerate: [ 0/1, 2147483647/1 ]

and the nvv4l2h264enc

SINK template: ‘sink’
Availability: Always
Capabilities:
video/x-raw(memory:NVMM)
width: [ 1, 2147483647 ]
height: [ 1, 2147483647 ]
format: { (string)I420, (string)NV12, (string)P010_10LE, (string)NV24 }
framerate: [ 0/1, 2147483647/1 ]

The nvdsosd src caps can work with NV12 and RGBA and the nvv4l2h264enc sink can NV12 as well beside many format. But they cannot be linked. However if I add the nvvideoconvert between them it works.

why it worked if I add the nvvideoconvert. although it has the same caps as the nvv4l2h264enc

3

Hi @nomeis,

You need to understand how caps work in GStreamer. Even if there is a caps intersection between the elements, the caps event comes from the upstream elements. The source is the first one to fixate caps; then, the second element negotiates caps with the third using transform_caps, get_caps, and fixate_caps. By the time you get to nvv4l2h264enc, the pipeline has already negotiated RGBA as a format, which is not supported by the encoder. You can add a capsfilter to try and force a particular set of caps at a certain point in the pipeline, but I think you will still need the converter because nvinfer will force RGBA.

4

Whether the plugins are connected depends on the format of your actual stream. For example, if the video format from nvdsosd is RGBA, it cannot link the nvv4l2h264enc.

5

I have added a filter between nvdsosd and nvv4l2h264enc to make it NV12 which should be accepted by nvv4l2h264enc

GstElement * filter1 = gst_element_factory_make (“capsfilter”, “filter1”);
GstCaps *caps1 = gst_caps_from_string (“video/x-raw(memory:NVMM), format=NV12”);
g_object_set (G_OBJECT (filter1), “caps”, caps1, NULL);
gst_caps_unref (caps1);

Still I get the same error

6

It won’t work if you add capsfilter to the nvdsosd . The nvdsosd plugin cannot convert the format of the stream.