I’m using the discoverer component to extract some info from a set of incoming streams, precisely I want to textract the codec in which the streaming comes to apply the proper pipeline.

My current code looks like this:

GError* error = nullptr;
std::string pipeline_str;
std::string stream_caps_str;
std::vector<std::string> stream_split_str;
                
if (Utils::String::stringContainsText(source_video, "&"))
{
    stream_split_str = Utils::String::split(source_video, "&", false);

    if (Utils::String::stringContainsText(stream_split_str[0], "?"))
    {
        std::vector<std::string> temp_str_vector = Utils::String::split(stream_split_str[0], "?", false);
        source_video = temp_str_vector[0] + "?" + stream_split_str[1] + " ";
    }
    else
        source_video = stream_split_str[0];
}
                
//This code obtains information from the incoming stream
GstDiscoverer* discoverer = gst_discoverer_new(3 * GST_SECOND, &error);
GstDiscovererInfo* discoverer_info = gst_discoverer_discover_uri(discoverer, source_video.c_str(), &error);
GstDiscovererStreamInfo* stream_info = gst_discoverer_info_get_stream_info(discoverer_info);

if(stream_info != NULL)
    stream_caps_str = gst_caps_to_string(gst_discoverer_stream_info_get_caps(stream_info));

PRINTF("CAPS INFO: %s\n", stream_caps_str.c_str());

//This part of the code sets the type of the pipeline for the incoming source stream, depending if it's rtsp or http
if (Utils::String::stringContainsText(source_video, "rtsp"))
    pipeline_str = "rtspsrc location=" + source_video + "latency=0";
else if (Utils::String::stringContainsText(source_video, "http"))
    pipeline_str = "souphttpsrc location=" + source_video;
else
    PRINTF("URL Source type not matching our system!\n");

pipeline_str += " is-live=true ! queue ";
                
//This switch sets the correct codec for encoding and decoding and if it's done in the GPU/CPU
//If there's no decoder set or the caps fail, it let's the program choose a codec automatically

switch (id_decoder)
{
    case STREAM_GST_CPU:
        if (Utils::String::stringContainsText(stream_caps_str, "H264"))
            pipeline_str += "! rtph264depay ! h264parse ! avdec_h264";
        else if (Utils::String::stringContainsText(stream_caps_str, "H265"))
            pipeline_str += "! rtph265depay ! h265parse ! avdec_h265"; 
        else if(Utils::String::stringContainsText(stream_caps_str, "JPEG"))
            pipeline_str += "! rtpjpegdepay ! jpegparse ! avdec_mjpeg";
        else
            pipeline_str += "! parsebin ! decodebin";
        break;
    case STREAM_GST_GPU:
        if (Utils::String::stringContainsText(stream_caps_str, "H264"))
            pipeline_str += "! rtph264depay ! h264parse ! nvh264dec";
        else if (Utils::String::stringContainsText(stream_caps_str, "H265"))
            pipeline_str += "! rtph265depay ! h265parse ! nvh265dec"; 
        else if (Utils::String::stringContainsText(stream_caps_str, "JPEG"))
            pipeline_str += "! rtpjpegdepay ! jpegparse ! nvjpegdec"; 
        else
            pipeline_str += " ! multipartdemux ! jpegparse ! nvjpegdec";

            pipeline_str += " ! cudaupload ! cudaconvert ! cudascale ! cudadownload";
        break;
        default:
            pipeline_str += "! parsebin ! decodebin";
            logNeuralAndPrint("ERROR: No se puede asignar ninguna pipeline especifica, se devuelve una pipeline generica.\n.");
        break;
}

pipeline_str += " ! videoconvert ! video/x-raw, format=BGR ";

pipeline_str += "! queue ! appsink name=stream sync=false";

GstElement* temp_pipeline = gst_parse_launch(pipeline_str.c_str(), &error);

My problem is that, to properly obtain the codec that the streaming is sending, I rely on the GstDiscovererStreamInfo* stream_info object, which for some streamings is null (EDIT: if it's NULL, it doesn't initialize the stream_caps_str variable, and then it defualts to a geenric pipeline), as they fail to get the infro using the Discoverer component.

These leads to that streaming to either, not fully complete the pipeline and not work at all, or start to be rendered using the default pipeline, which leads to some big visual artifacts and glitches.

For context, the URLs that fails follows the following pattern:

http://user:password@IP/mjpg/3/video.mjpg?resolution=854x480

While some other URLs with a similar layout work properly, the main difference is that those are rtsp,

I’ve also tried to use this IP in the CMD with the gst-discoverer-1.0 command, and it also fails to obtain the info through there, therefore my question is:

Does anyone know why these URLs fail ? If so, how should I solve it ?