vvas_xfilter - vvas_xfilter - 6.3 English - XD056

The vvas_xfilter is an infrastructure plug-in that extends the functionality of GstBaseTransform. This plug-in includes one input pad and one output pad, and it can efficiently operate with various types of acceleration software libraries, including the hard-kernel and software (user-space) acceleration libraries. The following figure illustrates this capability.

This plug-in can operate in the following three modes:

• Passthrough: Useful when the acceleration software library does not need to alter the input buffer.

• In-place: Useful when the acceleration software library needs to alter the input buffer.

• Transform: In this mode, for each input buffer, a new output buffer is produced.

You must set the mode using the JSON file. For information related to the kernels-config property, refer to JSON File Schema.

The vvas_xfilter plug-in can receive a configuration file as an input through the plug-in property named kernel-config. This configuration file, written in a JSON format, includes kernel-specific information required for the plug-in to function. Upon initialization, the vvas_xfilter plug-in parses the JSON file and completes the following actions:

• Locates the VVAS acceleration software library within the designated path and loads the shared library.

• Determines the acceleration software library type and prepares the acceleration software library handle (VVASKernel) to be used by the core APIs.

Input and Output

The vvas_xfilter accepts the buffers with the following color formats on input GstPad and output GstPad.

• GRAY8

• NV12

• BGR

• RGB

• YUY2

• r210

• v308

• GRAY10_LE32

• ABGR

• ARGB

The formats listed are the AMD IP supported color formats. To add other color formats, update the vvas_xfilter: <vvas>/vvas-gst-plugins/sys/filter/gstvvas_xfilter.c plugin as per the supported video formats of vvas_kernel.h : <vvas>/vvas-utils/utils/vvas/vvas_kernel.h#L76.

Control Parameters and Plug-in Properties

The following table lists the GObject properties exposed by the vvas_xfilter.

Signals

JSON Format for vvas_xfilter Plug-in

The following table provides the JSON keys accepted by the GStreamer vvas_xfilter plug-in.

The information in the following table is specific to the kernel chosen.

For insight into the implementation details, refer to the vvas_xfilter source code located at <vvas>/vvas-gst-plugins/sys/filter/.

Example JSON Configuration Files

JSON File for a Soft Library

The following JSON file is an example JSON file that can used with vvas_xfilter to control the xstub Soft kernel (software-kernel). The acceleration software library, libvvas_xstub.so, has three operation modes inplace, passthrough and transform and can be configured accordingly using json.

{
  "xclbin-location":"/run/media/mmcblk0p1/x_plus_ml.xclbin",
  "vvas-library-repo": "/usr/lib",
  "element-mode":"inplace",
  "kernel" :
  {
     "library-name":"libvvas_xstub.so",
      "config": {
        "kernel-lib-type" : "soft-lib",
        "element-mode" : "inplace",
        "src-stride-align" : 1,
        "src-height-align" : 1,
        "sink-stride-align" : 1,
        "sink-height-align" : 1,
        "debug-level" : 4
    }
  }
}

For how to develop acceleration software libraries that can be invoked through the vvas_xfilter plugin, refer to Acceleration-Software-Library-Development.

Dynamic Configuration of the Kernel

If you want to update the kernel configuration in runtime, make use of the dynamic-config property of vvas_xfilter. Set the configuration as a JSON format string to the dynamic-config property from a Gstreamer application in runtime as follows. Modify this JSON string as per your kernels and acceleration software library.

CONFIG_JSON_STRING = "{\"crop-x\": 20, \"crop-y\": 20, \"height\": 200, \"width\": 200 }"

g_object_set (vvas_xfilter, "dynamic-config", <CONFIG_JSON_STRING>  ,NULL);

The current user configuration string is passed to the acceleration library in the JSON format without any modification, where you can access it and update the kernel configuration in runtime.