fix param dump bug by changing decoder param sep from . to _

Author: berndpfrommer

README.md

@@ -105,8 +105,8 @@ command to find out what the proper parameter path is.
    to the decoder, like ``foo:bar,foobar:baz``. Default: empty string.
 - ``decoder_measure_performance`` enables performance
    measurements. Default: false.
-- ``decoders.<codec>.<av_source_pixel_format>.<cv_bridge_target_format>.<original_ros_encoding>`` specifies the decoders to use for a given FFMPEGPacket encoding.
-  If no decoders are specified for the full encoding, a less specific parameter will be tested, i.e. ``decoders.<codec>.<av_source_pixel_format>.<cv_bridge_target_format>``, then ``decoders.<codec>.<av_source_pixel_format>``, and finally ``decoders.<codec>``.
+- ``decoders.<codec>_<av_source_pixel_format>_<cv_bridge_target_format>_<original_ros_encoding>`` specifies the decoders to use for a given FFMPEGPacket encoding.
+  If no decoders are specified for the full encoding, a less specific parameter will be tested, i.e. ``decoders.<codec>_<av_source_pixel_format>_<cv_bridge_target_format>``, then ``decoders.<codec>_<av_source_pixel_format>``, and finally ``decoders.<codec>``.
   If all parameters are found to be empty, the Subscriber plugin will try to decode with a default set of libav decoders that support the appropriate codec.
 
 All parameters are prefixed again by the image topic and the transport, just like for the publisher node.

src/ffmpeg_subscriber.cpp

@@ -122,7 +122,7 @@ std::string FFMPEGSubscriber::getDecodersFromMap(const std::string & encoding)
   for (int i = static_cast<int>(x.size()); i > 0; --i) {
     std::string p_name;
     for (int j = 0; j < i; j++) {
-      p_name += "." + x[j];
+      p_name += (j == 0 ? "." : "_") + x[j];
     }
     ParameterDefinition pdef{
       PValue(""), PDescriptor()

test/test_1.cpp

@@ -192,7 +192,7 @@ void lossless_compression_test(
   auto sub_node = std::make_shared<TestSubscriber>(ns, sub_options);
   // must use hevc, for some reason hevc_cuvid will not deliver the last frame
   sub_node->setParameterBase(parameter_base);
-  sub_node->setParameter<std::string>("decoders.hevc.gray.bgr8.mono8", decoders);
+  sub_node->setParameter<std::string>("decoders.hevc_gray_bgr8_mono8", decoders);
   sub_node->initialize();  // only after params have been set!
   exec.add_node(sub_node);
   while (pub_node->publish_next() && rclcpp::ok()) {