Users may alter behaviors by supplying the "nnstreamer.ini" file or updating environmental variables.

There are three layers of configurations, with higher priority from the top:

• Environmental variables (highest priority,)
• Configuration file (if not specified, it's /etc/nnstreamer.ini)
• Hardcoded default values (lowest priority)

Note: in Tizen, you cannot specify the location of nnstreamer.ini with env-var.

For search locations, files in the locations of higher priorities are found first.

For other values, the values configured with higher priorities override those with lower priorities.

Environmental Variables

• NNSTREAMER_FILTERS: the search location for tensor-filter subplugins
• NNSTREAMER_DECODERS: the search location for tensor-decoder subplugins
• NNSTREAMER_CUSTOMFILTERS: the search location for custom tensor-filters.
  • Note that users may specify the full absolute path of a custom filter to ignore this effect.
• NNSTREAMER_CONVERTERS: the search location for tensor-converter subplugins
• NNSTREAMER_CONF: the path to .ini NNStreamer configuration file. (/etc/nnstreamer.ini if not specified)

The intention of these is to override default values of .ini files without the capability/need to update /etc/nnstreamer.ini file in run-time.

However, in many embedded devices, as in Tizen, such capabilities are prohibited for security reasons.

Configuration File (.ini, /etc/nnstreamer.ini by default)

• 
  

  [common] enable_envvar=true/false # You may disable NNStreamer's environmental variables with this. # However, with envvar, the location of nnstreamer.ini may be altered. # Thus, this is effective only NNSTREAMER_CONF envvar is disabled (__TIZEN__ disables it) enable_symlink=true/false # If this is false, subplugin files should not be sym-linked. (regular files only) [filter] filters=PATH # The search location for tensor-filter subplugins # By default, /usr/lib/nnstreamer/filters/ customfilters=PATH # The search location for custom tensor-filters. # By default, /usr/lib/nnstreamer/customfilters/ # Note that users may specify the full absolute path of a custom filter to ignore this effect. framework_priority_tflite=FW1,FW2,FW3,... # If a .tflite file is given for tensor-filter or "Single" API, # which neuural network framework should be used. # If multiple frameworks are given, NNStreamer will try # from the left. # By default, tensorflow-lite,nnfw,armnn,edgetpu [decoder] decoders=PATH # The search location for tensor-decoder subplugins # By default, /usr/lib/nnstreamer/decoders/ [converter] converters=PATH # The search location for tensor-converter subplugins # By default, /usr/lib/nnstreamer/converters/ [element-restriction] restricted-element=element1,element2,element3,... # If this is set, only the GStreamer elements in the list and NNStreamer's elements are allowed with NNStreamer "Pipeline" API. # We know that the ,ini configuration name is weird and we may update it soon. (e.g., allowed-elements) # If you do not want to restrict the usage of GStreamer elements, do not define this configuration key. [tensorflowlite] enable_nnapi=true/false # For tensorflow-lite subplugin, enable NNAPI. This can be overriden for each instance with GStreamer property values in a pipeline. [pytorch] enable_use_gpu=true/false # For pytorch subplugin, enable GPU. This can be overriden for each instance with GStreamer property values in a pipeline.

  
  

Hardcoded Default Values

• Ini file location: /etc/nnstreamer.ini
• Filter subplugin path: /usr/lib/nnstreamer/filters/
• Decoder subplugin path: /usr/lib/nnstreamer/decoders/
• Custom filter paths: /usr/lib/nnstreamer/customfilters/
  • Note that users may specify the full absolute path of a custom filter to ignore this effect.
• Converter subplugin path: /usr/lib/nnstreamer/converters/

Related Code: /gst/nnstreamer/nnstreamer_conf.{c, h}

Updated at 2020-04-07, based on commit 5ed942e6, (NNStreamer 1.5.1)