gstrplaybinをカスタムビデオシンクにリンクするvideoconvertとシンクしてgstreamerをリンクしない

Question

パイプラインからgstreamerアプリケーションを作成しようとしています：gst-launch-1.0 playbin uri = rtsp：// video-sink = "videoconvert！video/x-raw、width = 720、高さ= 480！ximagesink "

リンク要素にエラーが発生しました。私のコードを投稿する：

#include <gst/gst.h> 

int main(int argc, char *argv[]) { 
    GstElement *source, *videosink, *pipeline, *videoconvert; 
    GstCaps *capsFilter; 
    GstBus *bus; 
    GstMessage *msg; 
    GstPad *pad; 
    gboolean link_ok; 

    /* Initialize GStreamer */ 
    gst_init (&argc, &argv); 


    /* Create Elements */ 
    pipeline = gst_pipeline_new("my-pipeline"); 
    source = gst_element_factory_make ("playbin", "source"); 
    videoconvert = gst_element_factory_make("videoconvert", "convert"); 
    videosink = gst_element_factory_make("ximagesink", "autovideosink"); 

    /* set property value */ 
    g_object_set (source, "uri", "rtsp:<file location>", NULL); 

    if (!pipeline || !source || !videoconvert || !videosink) 
    { 
      g_printerr ("Not all elements could be created.\n"); 
      return; 
    } 


    gst_bin_add_many (GST_BIN(pipeline), videoconvert, videosink, NULL); 
    capsFilter = gst_caps_new_simple("video/x-raw", 
        "width", G_TYPE_INT, 176, 
        "height", G_TYPE_INT, 144, 
        NULL); 
    link_ok = gst_element_link_filtered(videoconvert,videosink, capsFilter); 
    gst_caps_unref (capsFilter); 

    if (!link_ok) { 
      g_warning ("Failed to link element1 and element2!"); 
    } 
    if (gst_element_link_many(videoconvert, videosink, NULL) != TRUE) { 
      g_print ("Failed to link some elements .....1 !\n"); 
      gst_object_unref (pipeline); 
      return -1; 
    } 


     /* Start playing */ 
    gst_element_set_state (source, GST_STATE_PLAYING); 

    /* Wait until error or EOS */ 
    bus = gst_element_get_bus (source); 
    msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, 
GST_MESSAGE_ERROR | GST_MESSAGE_EOS); 

Answer 1

playbin要素が沈むSRCからの完全なパイプラインを与えることに留意すべきであるので、シンクもののないパイプラインが完全に再生されました：

gst-launch-1.0 playbin uri=rtsp://127.0.0.1:8551/test 

正しいパイプラインをそのあなたが作成したいことは次である：

gst-launch-1.0 playbin uri=rtsp://127.0.0.1:8551/test video-sink="videoconvert ! video/x-raw,width=320,height=240 ! ximagesink" 

のGStreamerアプリケーションにこれを埋め込むためには、すべての要素をリンクする必要はありません。代わりに、カスタムビデオ出力ビンを作成し、playbinのvideo-sinkプロパティに設定する必要があります。つまり、ビンを作成して必要な要素をリンクし、playbinにvideo-sinkプロパティを使用するよう指示することです。また、ビンのGhostPadを作成し、ビン内の最初の要素のシンクパッドにポイントする必要があります。

これが結果です：

#include <gst/gst.h> 

int main(int argc, char *argv[]) { 
    GstElement *source, *videosink, *pipeline, *videoconvert, *customoutput; 
    GstCaps *capsFilter; 
    GstBus *bus; 
    GstMessage *msg; 
    GstPad *pad; 
    gboolean add_ok; 
    gboolean link_ok; 
    GstStateChangeReturn ret; 
    GMainLoop *loop; 

    /* Initialize GStreamer */ 
    gst_init (&argc, &argv); 
    loop = g_main_loop_new (NULL, FALSE); 


    /* Create Elements */ 
    pipeline = gst_pipeline_new("my-pipeline"); 
    source = gst_element_factory_make ("playbin", "source"); 
    videoconvert = gst_element_factory_make("videoconvert", "videoconvert"); 
    capsFilter = gst_caps_new_simple("video/x-raw", 
        "width", G_TYPE_INT, 320, 
        "height", G_TYPE_INT, 240, 
        NULL); 
    videosink = gst_element_factory_make("ximagesink", "videosink"); 
    customoutput = gst_bin_new("customoutput"); 

    // It is possible to create the bin like this 
    // Ghost pads on the bin for unlinked source or sink pads within the bin can automatically be created 
    // customoutput = gst_parse_bin_from_description ("videoconvert ! video/x-raw,width=320 ! ximagesink", TRUE, NULL); 
    gst_bin_add_many (GST_BIN (customoutput), videoconvert, videosink, NULL); 

    link_ok = gst_element_link_filtered(videoconvert,videosink, capsFilter); 
    gst_caps_unref (capsFilter); 
    if (!link_ok) { 
      g_warning ("Failed to link element1 and element2!"); 
    } 

    GstPad *sinkpad,*ghost_sinkpad; 
    sinkpad = gst_element_get_static_pad (videoconvert, "sink"); 
    ghost_sinkpad = gst_ghost_pad_new ("sink", sinkpad); 
    gst_pad_set_active (ghost_sinkpad, TRUE); 
    gst_element_add_pad (customoutput, ghost_sinkpad); 

    /* set property value */ 
    g_object_set (source, "video-sink", customoutput, NULL); 
    g_object_set (source, "uri", "rtsp://127.0.0.1:8551/test", NULL); 

    if (!pipeline || !source || !videoconvert || !capsFilter || !videosink || !customoutput) 
    { 
      g_printerr ("Not all elements could be created.\n"); 
      return -1; 
    } 

    gst_bin_add_many (GST_BIN(pipeline), source,NULL); 

    // Start playing */ 
    ret = gst_element_set_state (pipeline, GST_STATE_PLAYING); 
    g_print ("Running...\n"); 
    g_main_loop_run (loop); 
    if (ret == GST_STATE_CHANGE_FAILURE) { 
     g_printerr ("Unable to set the pipeline to the playing state.\n"); 
     gst_object_unref (pipeline); 
     return -1; 
    } 
    /* Wait until error or EOS */ 
    //bus = gst_element_get_bus (pipeline); 
    //msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE,GST_MESSAGE_ERROR | GST_MESSAGE_EOS); 

     /* Free resources */ 
    gst_object_unref (bus); 
    gst_element_set_state (pipeline, GST_STATE_NULL); 
    gst_object_unref (pipeline); 
    g_main_loop_unref (loop); 

    return 0; 
}