[DLStreamer Pipeline Server] WebRTC GPU pipeline fallback to software encoding when vah264enc is missing

[sajeevrajput]

Description

When running WebRTC on platforms that donot have vah264enc gstreamer plugin and the primary pipeline feeds GPU buffers, the secondary pipeline i.e. webrtc pipeline will fail complaining the element is unavailable.
As a workaround, we will fallback to use software encoder (x264enc) instead if the plugin is missing.

Fixes # (issue)
https://jira.devtools.intel.com/browse/ITEP-74078

Any Newly Introduced Dependencies

None

How Has This Been Tested?

sanity tested
CPU pipeline on Core and Xeon(Platinum 8468V)
GPU pipeline on Core and Xeon(Platinum 8468V with dGPU)

DLSPS pipeline

{
    "config": {
        "pipelines": [
            {
                "name": "pallet_defect_detection",
                "source": "gstreamer",
                "queue_maxsize": 50,
                "pipeline": "{auto_source} name=source ! parsebin ! vah264dec ! vapostproc ! video/x-raw(memory:VAMemory) ! gvadetect device=GPU pre-process-backend=va-surface-sharing model-instance-id=inst0 name=detection ! queue ! gvametaconvert add-empty-results=true name=metaconvert ! gvametapublish name=destination ! queue ! gvafpscounter ! appsink name=appsink",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "detection-properties": {
                            "element": {
                                "name": "detection",
                                "format": "element-properties"
                            }
                        }
                    }
                },
                "auto_start": false
            }
        ]
    }
}

CURL command

curl --location '<HOST_IP>:8080/pipelines/user_defined_pipelines/pallet_defect_detection' \
--header 'Content-Type: application/json' \
--data '{
    "source": {
        "uri": "file:///home/pipeline-server/resources/videos/classroom.avi",
        "type": "uri"
    },
    "destination": {
        "metadata": {
            "type": "file",
            "path": "/tmp/results8.jsonl",
            "format": "json-lines"
        },
        "frame": {
            "type": "webrtc",
            "peer-id": "pdd"
        }
    },
    "parameters": {
        "detection-properties": {
            "model": "/home/pipeline-server/resources/models/geti/pallet_defect_detection/deployment/Detection/model/model.xml",
            "device": "GPU"
        }
    }
}'

Checklist:

• I agree to use the APACHE-2.0 license for my code changes.
• I have not introduced any 3rd party components incompatible with APACHE-2.0.
• I have not included any company confidential information, trade secret, password or security token.
• I have performed a self-review of my code.

[rrajore]

LGTM