我尝试编写的应用程序根据网络上的视频服务器获取视频流，并在winforms窗口中显示（后来我希望在WPF中托管相同类型的控件）。我正在使用gstreamer-sharp，因为我的应用程序基于c＃.net。
我成功地根据this answer中的代码示例运行了videotestsrc，并且能够使用VideoOverlayAdapter和一组winForms面板创建窗口中所需的testvideosrc的多个实例。
当我开始让rtspsrc做同样的事情时，我自然遇到了一些我想要过去的障碍，我班上的代码就在下面。
我没有在初始化代码中链接rtspsrc，而是相信我需要将rtspsrc的新pad链接到下一个元素（在本例中为rtph264depay），这就是我遇到麻烦的地方。
PadAdded事件似乎有时会在启动程序的几秒钟内被解雇，有时根本不会被解雇？服务器可以使用gstreamer-sharp版本的基本教程（第1部分），并具有良好的延迟（容易小于300毫秒，但我需要在应用程序运行后进行玻璃到玻璃测试）。
一旦PadAdded事件最终触发，我在尝试将新打击垫链接到rtph264depay接收器垫时会获得NOFORMAT状态。
我还注意到我似乎没有得到准备窗口处理总线同步消息，我将像gstVideoOverlay示例中那样设置视频覆盖适配器（所以我不会输出到我需要的窗口句柄如果垫连接成功）。
我一直无法找到这个特殊问题（rtspsrc pad没有链接到rtph264depay接收器），因为类似的问题似乎是关于将其他元素链接在一起。
根据调试消息，初始化代码中其余元素的初始链接是成功的。
最终目标是将帧放入OpenCV / Emgu并进行一些分析和基本覆盖工作。
对此的任何帮助将不胜感激。
非常感谢！
/// <summary>
/// class to create a gstreamer pipeline based on an rtsp stream at the provided URL
/// </summary>
class gstPipeline2
{
// elements for the pipeline
private Element rtspsrc, rtph264depay, decoder, videoConv, videoSink;
private System.Threading.Thread mainGLibThread;
private GLib.MainLoop mainLoop;
// the window handle (passed in)
private IntPtr windowHandle;
// our pipeline
private Pipeline currentPipeline = null;
/// <summary>
/// Create a new gstreamer pipeline rendering the stream at URL into the provided window handle
/// </summary>
/// <param name="WindowHandle">The handle of the window to render to </param>
/// <param name="Url">The url of the video stream</param>
public gstPipeline2(IntPtr WindowHandle, string Url)
{
windowHandle = WindowHandle; // get the handle and save it locally
// initialise the gstreamer library and associated threads (for diagnostics)
Gst.Application.Init();
mainLoop = new GLib.MainLoop();
mainGLibThread = new System.Threading.Thread(mainLoop.Run);
mainGLibThread.Start();
// create each element now for the pipeline
// starting with the rtspsrc
rtspsrc = ElementFactory.Make("rtspsrc", "udpsrc0"); // create an rtsp source
rtspsrc["location"] = Url; // and set its location (the source of the data)
rtph264depay = ElementFactory.Make("rtph264depay", "rtph264depay0");
decoder = ElementFactory.Make("avdec_h264", "decoder0");
videoConv = ElementFactory.Make("videoconvert", "videoconvert0");
videoSink = ElementFactory.Make("autovideosink", "sink0"); // and finally the sink to render the video (redirected to the required window handle below in Bus_SyncMessage() )
// create our pipeline which links all the elements together into a valid data flow
currentPipeline = new Pipeline("pipeline");
currentPipeline.Add(rtspsrc, rtph264depay, decoder, videoConv, videoSink); // add the required elements into it
// link the various bits together in the correct order
if(!rtph264depay.Link(decoder))
System.Diagnostics.Debug.WriteLine("rtph264depay could not be linked to decoder (bad)");
else
System.Diagnostics.Debug.WriteLine("rtph264depay linked to decoder (good)");
if (!decoder.Link(videoConv))
System.Diagnostics.Debug.WriteLine("decoder could not be linked to videoconvert (bad)");
else
System.Diagnostics.Debug.WriteLine("decoder linked to videoconvert (good)");
if (!videoConv.Link(videoSink))
System.Diagnostics.Debug.WriteLine("videoconvert could not be linked to autovideosink (bad)");
else
System.Diagnostics.Debug.WriteLine("videoconvert linked to autovideosink (good)");
rtspsrc.PadAdded += Rtspsrc_PadAdded; // subscribe to the PadAdded event so we can link new pads (sources of data?) to the depayloader when they arrive
// subscribe to the messaging system of the bus and pipeline so we can minotr status as we go
Bus bus = currentPipeline.Bus;
bus.AddSignalWatch();
bus.Message += Bus_Message;
bus.EnableSyncMessageEmission();
bus.SyncMessage += Bus_SyncMessage;
// finally set the state of the pipeline running so we can get data
var setStateReturn = currentPipeline.SetState(State.Null);
System.Diagnostics.Debug.WriteLine("SetStateNULL returned: " + setStateReturn.ToString());
setStateReturn = currentPipeline.SetState(State.Ready);
System.Diagnostics.Debug.WriteLine("SetStateReady returned: " + setStateReturn.ToString());
setStateReturn = currentPipeline.SetState(State.Playing);
System.Diagnostics.Debug.WriteLine("SetStatePlaying returned: " + setStateReturn.ToString());
}
private void Rtspsrc_PadAdded(object o, PadAddedArgs args)
{
System.Diagnostics.Debug.WriteLine("Rtspsrc_PadAdded: called with new pad named: " + args.NewPad.Name);
// a pad has been added to the source so we need to link it to the rest of the pipeline to ultimately display it onscreen
Pad sinkPad = rtph264depay.GetStaticPad("sink"); // get the sink pad for the one we have recieved so we can link to the depayloader element
System.Diagnostics.Debug.WriteLine("Rtspsrc_PadAdded: rtps264depay sink pad returned: " + sinkPad.Name);
PadLinkReturn ret = args.NewPad.Link(sinkPad);
System.Diagnostics.Debug.WriteLine("Rtspsrc_PadAdded: link attempt returned: " + ret.ToString());
}
public void killProcess()
{
mainLoop.Quit();
}
private void Bus_SyncMessage(object o, SyncMessageArgs args)
{
if (Gst.Video.Global.IsVideoOverlayPrepareWindowHandleMessage(args.Message))
{
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Message prepare window handle received by: " + args.Message.Src.Name + " " + args.Message.Src.GetType().ToString());
if (args.Message.Src != null)
{
// these checks were in the testvideosrc example and failed, args.Message.Src is always Gst.Element???
if (args.Message.Src is Gst.Video.VideoSink)
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is VideoSink");
else
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is NOT VideoSink");
if (args.Message.Src is Gst.Bin)
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is Bin");
else
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is NOT Bin");
try
{
args.Message.Src["force-aspect-ratio"] = true;
}
catch (PropertyNotFoundException) { }
try
{
Gst.Video.VideoOverlayAdapter adapter = new VideoOverlayAdapter(args.Message.Src.Handle);
adapter.WindowHandle = windowHandle;
adapter.HandleEvents(true);
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Handle passed to adapter: " + windowHandle.ToString());
}
catch (Exception ex) { System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Exception Thrown (overlay stage): " + ex.Message); }
}
}
else
{
string info;
IntPtr prt;
args.Message.ParseInfo(out prt, out info);
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: " + args.Message.Type.ToString() + " - " + info);
}
}
private void Bus_Message(object o, MessageArgs args)
{
var msg = args.Message;
//System.Diagnostics.Debug.WriteLine("HandleMessage received msg of type: {0}", msg.Type);
switch (msg.Type)
{
case MessageType.Error:
//
GLib.GException err;
string debug;
System.Diagnostics.Debug.WriteLine("Bus_Message: Error received: " + msg.ToString());
break;
case MessageType.StreamStatus:
Gst.StreamStatusType status;
Element theOwner;
msg.ParseStreamStatus(out status, out theOwner);
System.Diagnostics.Debug.WriteLine("Bus_Message: Case SteamingStatus: status is: " + status + " ; Owner is: " + theOwner.Name);
break;
case MessageType.StateChanged:
State oldState, newState, pendingState;
msg.ParseStateChanged(out oldState, out newState, out pendingState);
if (newState == State.Paused)
args.RetVal = false;
System.Diagnostics.Debug.WriteLine("Bus_Message: Pipeline state changed from {0} to {1}: ; Pending: {2}", Element.StateGetName(oldState), Element.StateGetName(newState), Element.StateGetName(pendingState));
break;
case MessageType.Element:
System.Diagnostics.Debug.WriteLine("Bus_Message: Element message: {0}", args.Message.ToString());
break;
default:
System.Diagnostics.Debug.WriteLine("Bus_Message: HandleMessage received msg of type: {0}", msg.Type);
break;
}
args.RetVal = true;
}
}
答案 0 :(得分：0)
好的，我设法解决了我遇到的问题。
第一个问题（添加的垫没有被一致地调用）似乎是通过构建x64而不是任何cpu或x86来修复的。我怀疑我的gstreamer库的安装没有正确完成。
第二个问题（连接新垫时为NOFORMAT）需要更多工作。最后，我遵循了Florian的建议，并查看了使用uridecodebin作为源，并将新垫直接链接到autovideosink ....中间没有元素。
我现在添加了一个一致的新pad，每次都会发送准备窗口处理总线同步消息。我有四个独立的IP流，现在有四个winforms面板具有良好的延迟（仍然是测试玻璃到玻璃）。
为了确保延迟（有点）调整，我必须深入研究uridecodebin的源设置信号，并假设源是rtspsrc类型，然后设置它的“延迟”属性。下面的代码没有验证源类型，所以YMMV，你可能会在这里得到一个例外。
请参阅以下适用于我的课程的源代码（编译为x64）。
希望这对那里的任何人都有所帮助。
现在进入appsink !! ：）
/// <summary>
/// class to create a gstreamer pipeline based on an rtsp stream at the provided URL
/// </summary>
class gstPipeline2
{
// elements for the pipeline
private Element uriDecodeBin, videoSink;
private System.Threading.Thread mainGLibThread;
private GLib.MainLoop mainLoop;
// the window handle (passed in)
private IntPtr windowHandle;
// our pipeline
private Pipeline currentPipeline = null;
/// <summary>
/// Create a new gstreamer pipeline rendering the stream at URL into the provided window handle
/// </summary>
/// <param name="WindowHandle">The handle of the window to render to </param>
/// <param name="Url">The url of the video stream</param>
public gstPipeline2(string Url, IntPtr WindowHandle)
{
windowHandle = WindowHandle; // get the handle and save it locally
// initialise the gstreamer library and associated threads (for diagnostics)
Gst.Application.Init();
mainLoop = new GLib.MainLoop();
mainGLibThread = new System.Threading.Thread(mainLoop.Run);
mainGLibThread.Start();
// create each element now for the pipeline
uriDecodeBin = ElementFactory.Make("uridecodebin", "uriDecodeBin0"); // create an uridecodebin (which handles most of the work for us!!)
uriDecodeBin["uri"] = Url; // and set its location (the source of the data)
videoSink = ElementFactory.Make("autovideosink", "sink0"); // and finally the sink to render the video (redirected to the required window handle below in Bus_SyncMessage() )
// create our pipeline which links all the elements together into a valid data flow
currentPipeline = new Pipeline("pipeline");
currentPipeline.Add(uriDecodeBin, videoSink); // add the required elements into it
uriDecodeBin.PadAdded += uriDecodeBin_PadAdded; // subscribe to the PadAdded event so we can link new pads (sources of data?) to the depayloader when they arrive
uriDecodeBin.Connect("source-setup", SourceSetup); // subscribe to the "source-setup" signal, not quite done in the usual C# eventing way but treat it as essentially the same
// subscribe to the messaging system of the bus and pipeline so we can monitor status as we go
Bus bus = currentPipeline.Bus;
bus.AddSignalWatch();
bus.Message += Bus_Message;
bus.EnableSyncMessageEmission();
bus.SyncMessage += Bus_SyncMessage;
// finally set the state of the pipeline running so we can get data
var setStateReturn = currentPipeline.SetState(State.Null);
System.Diagnostics.Debug.WriteLine("SetStateNULL returned: " + setStateReturn.ToString());
setStateReturn = currentPipeline.SetState(State.Ready);
System.Diagnostics.Debug.WriteLine("SetStateReady returned: " + setStateReturn.ToString());
setStateReturn = currentPipeline.SetState(State.Playing);
System.Diagnostics.Debug.WriteLine("SetStatePlaying returned: " + setStateReturn.ToString());
}
private void uriDecodeBin_PadAdded(object o, PadAddedArgs args)
{
System.Diagnostics.Debug.WriteLine("uriDecodeBin_PadAdded: called with new pad named: " + args.NewPad.Name);
// a pad has been added to the source so we need to link it to the rest of the pipeline to ultimately display it onscreen
Pad sinkPad = videoSink.GetStaticPad("sink"); // get the pad for the one we have recieved so we can link to the depayloader element
System.Diagnostics.Debug.WriteLine("uriDecodeBin_PadAdded: queue pad returned: " + sinkPad.Name);
PadLinkReturn ret = args.NewPad.Link(sinkPad);
System.Diagnostics.Debug.WriteLine("uriDecodeBin_PadAdded: link attempt returned: " + ret.ToString());
}
void SourceSetup(object sender, GLib.SignalArgs args)
{
// we need to delve into the source portion of the uridecodebin to modify the "latency" property, need to add some validation here to ensure this is an rtspsrc
var source = (Element)args.Args[0];
System.Diagnostics.Debug.WriteLine("SourceSetup: source is named: " + source.Name + ", and is of type: " + source.NativeType.ToString());
source["latency"] = 0; // this COULD throw an exception if the source is not rtspsrc or similar with a "latency" property
}
public void killProcess()
{
mainLoop.Quit();
}
private void Bus_SyncMessage(object o, SyncMessageArgs args)
{
if (Gst.Video.Global.IsVideoOverlayPrepareWindowHandleMessage(args.Message))
{
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Message prepare window handle received by: " + args.Message.Src.Name + " " + args.Message.Src.GetType().ToString());
if (args.Message.Src != null)
{
// these checks were in the testvideosrc example and failed, args.Message.Src is always Gst.Element???
if (args.Message.Src is Gst.Video.VideoSink)
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is VideoSink");
else
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is NOT VideoSink");
if (args.Message.Src is Gst.Bin)
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is Bin");
else
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: source is NOT Bin");
try
{
args.Message.Src["force-aspect-ratio"] = true;
}
catch (PropertyNotFoundException) { }
try
{
Gst.Video.VideoOverlayAdapter adapter = new VideoOverlayAdapter(args.Message.Src.Handle);
adapter.WindowHandle = windowHandle;
adapter.HandleEvents(true);
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Handle passed to adapter: " + windowHandle.ToString());
}
catch (Exception ex) { System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: Exception Thrown (overlay stage): " + ex.Message); }
}
}
else
{
string info;
IntPtr prt;
args.Message.ParseInfo(out prt, out info);
System.Diagnostics.Debug.WriteLine("Bus_SyncMessage: " + args.Message.Type.ToString() + " - " + info);
}
}
private void Bus_Message(object o, MessageArgs args)
{
var msg = args.Message;
//System.Diagnostics.Debug.WriteLine("HandleMessage received msg of type: {0}", msg.Type);
switch (msg.Type)
{
case MessageType.Error:
//
GLib.GException err;
string debug;
System.Diagnostics.Debug.WriteLine("Bus_Message: Error received: " + msg.ToString());
break;
case MessageType.StreamStatus:
Gst.StreamStatusType status;
Element theOwner;
msg.ParseStreamStatus(out status, out theOwner);
System.Diagnostics.Debug.WriteLine("Bus_Message: Case SteamingStatus: status is: " + status + " ; Owner is: " + theOwner.Name);
break;
case MessageType.StateChanged:
State oldState, newState, pendingState;
msg.ParseStateChanged(out oldState, out newState, out pendingState);
if (newState == State.Paused)
args.RetVal = false;
System.Diagnostics.Debug.WriteLine("Bus_Message: Pipeline state changed from {0} to {1}: ; Pending: {2}", Element.StateGetName(oldState), Element.StateGetName(newState), Element.StateGetName(pendingState));
break;
case MessageType.Element:
System.Diagnostics.Debug.WriteLine("Bus_Message: Element message: {0}", args.Message.ToString());
break;
default:
System.Diagnostics.Debug.WriteLine("Bus_Message: HandleMessage received msg of type: {0}", msg.Type);
break;
}
args.RetVal = true;
}
}