c++ - GStreamer:rtpjpegdepay/jpegdec 输出的帧颜色错误

Question

MJPEG RTSP 流服务器已使用 VLC 运行。然后我又运行了一个 VLC 以确定来自流的帧具有正确的颜色。所有颜色都是正确的。

我的任务是在没有任何解压缩的情况下在 rtpjpegdepay 插件的输出上捕获 MJPEG 帧。我已经使用以下管道创建了 C++ 应用程序:

rtspsrc -> rtpjpegdepay -> appsink 

源 URL 是使用下面的行设置的:

g_object_set(G_OBJECT(m_source), "location", url.c_str(), NULL);

每个 jpeg 帧都是用下面的方法捕获的:

g_signal_connect(m_sink, "new-sample", G_CALLBACK(captureGstBuffer), this);

但是收到的图片很奇怪(是有分隔带的路，只有颜色不对):

接下来我尝试使用另一个管道:

rtspsrc -> rtpjpegdepay -> jpegdec -> appsink

使用相同的“新样本”方法，我收到的 YUV420 图像具有与 rtpjpegdepay 相同的错误颜色。

我尝试了从 1.8.3 到 1.14.2 的不同版本的 Gstreamer

这种行为的原因可能是什么？

这是代码(YUV420):

static void OnPadAdded(GstElement *element, GstPad *pad, void *data)
{
    GstElement *rtpjpeg = GST_ELEMENT(data);
    GstPad *sinkpad;

    sinkpad = gst_element_get_static_pad(rtpjpeg, "sink");
    gst_pad_link(pad, sinkpad);
    gst_object_unref(sinkpad);
}

static int fileind = 0;

void WriteToFile(BYTE *pBuffer, DWORD dwBufSize)
{
    fileind++;

    std::stringstream ssFileName;
    ssFileName << "D:\\Temp\\file" << fileind << ".yuv";
    FILE* fp = fopen(ssFileName.str().c_str(), "wb+");
    fwrite(pBuffer, dwBufSize, 1, fp);
    fclose(fp);
}

static GstFlowReturn CaptureGstBuffer(GstElement *sink, void *data) {
    GstSample *sample;

    g_signal_emit_by_name(sink, "pull-sample", &sample);
    if (sample) {

        GstBuffer *buffer = gst_sample_get_buffer(sample);

        GstMapInfo map;
        gst_buffer_map(buffer, &map, GST_MAP_READ);

        WriteToFile((BYTE *)map.data, map.size);

        gst_buffer_unmap(buffer, &map);
        gst_sample_unref(sample);
    }

    return GST_FLOW_OK;
}

long RTSPClientDevice::StartClient()
{
   m_loop = g_main_loop_new(NULL, FALSE);

   m_pipeline = gst_pipeline_new("mjpeg-catcher");
   g_assert(m_pipeline);
   m_source = gst_element_factory_make("rtspsrc", "Source");
   g_assert(m_source);
   m_depay = gst_element_factory_make("rtpjpegdepay", "Depay");
   g_assert(m_depay);
   m_decoder = gst_element_factory_make("jpegdec", "Decoder");
   g_assert(m_decoder);
   m_sink = gst_element_factory_make("appsink", "Output");
   g_assert(m_sink);

   if (!m_pipeline || !m_source || !m_depay || !m_decoder || !m_sink) {
        return Z_ERR;
   }

   std::string url = "";
   GetClientURL(url);

   g_object_set(G_OBJECT(m_source), "location", url.c_str(), NULL);
   g_object_set(G_OBJECT (m_source), "do-rtcp", 1, NULL);
   g_object_set(G_OBJECT(m_source), "latency", 0, NULL);
   g_object_set(G_OBJECT(m_source), "probation", 1, NULL);

   m_bus = gst_pipeline_get_bus(GST_PIPELINE(m_pipeline));
   gst_bus_add_watch(m_bus, bus_call, m_loop);
   gst_object_unref(m_bus);

   gst_bin_add_many(GST_BIN(m_pipeline), m_source, m_depay, m_decoder , 
m_sink, NULL);

   if (!gst_element_link(m_source, m_depay)) {
      return Z_ERR;
   }

   if (!gst_element_link(m_depay, m_decoder)) {
      return Z_ERR;
   }

   if (!gst_element_link(m_decoder, m_sink)) {
      return Z_ERR;
   }

   if (!g_signal_connect(m_source, "pad-added", G_CALLBACK(OnPadAdded), 
   m_capsfilter))
   {
      return Z_ERR;
   }

   g_object_set(G_OBJECT(m_sink), "emit-signals", TRUE, "sync", FALSE, NULL);
   g_object_set(G_OBJECT(m_sink), "max-buffers", (guint)1, NULL);
   g_object_set(G_OBJECT(m_sink), "drop", (guint)1, NULL);
   g_object_set(G_OBJECT(m_sink), "sync", (guint)0, NULL);
   g_object_set(G_OBJECT(m_sink), "max_lateness", G_GINT64_CONSTANT(-1), NULL);
   g_object_set(G_OBJECT(m_sink), "qos", (guint)1, NULL);


   /*GstCaps *caps = gst_caps_from_string("video/x-raw,encoding-name=RGB,format=(fourcc)YUV444,width=1280,height=720");
   g_object_set(m_videoconvert, "caps", caps, NULL);
   gst_caps_unref(caps);*/

   if (g_signal_connect(m_sink, "new-sample", G_CALLBACK(CaptureGstBuffer), this) <= 0)
   {
      return Z_ERR;
   }

   gst_element_set_state(m_pipeline, GST_STATE_PLAYING);

   ControlThreadStart(); //Place for g_main_loop_run

   m_isStarted = true;

   return Z_OK;
 }

 long RTSPClientDevice::StopClient()
 {
   if(!m_isStarted)
   {
     return Z_OK;
   }

   if (g_main_loop_is_running(m_loop))
   {
       g_main_loop_quit(m_loop);
       g_main_context_wakeup(g_main_loop_get_context(m_loop));
   }

   gst_element_set_state(m_pipeline, GST_STATE_NULL);
   gst_object_unref(GST_OBJECT(m_pipeline));
   //TODO: unref plugins

   g_main_loop_unref(m_loop);

   m_isStarted = false;

   return Z_OK;
 }

已编辑:

我尝试使用以下内容:

gst-launch-1.0.exe -v rtspsrc location = rtsp://127.0.0.1:554/Streaming/Channels/101 ! rtpjpegdepay ! jpeg解析! multifilesink post-messages=true location="frame%d.jpg"

结果相同 - 颜色错误。

命令:

gst-launch-1.0.exe -v rtspsrc location = rtsp://127.0.0.1:554/Streaming/Channels/101 ! rtpjpegdepay ! multifilesink post-messages=true location="frame%d.jpg"

也产生相同的帧

我还捕获了来自 gst-launch-1.0 的日志(看不到错误 - 只有 INFO 和 DEBUG)和 wireshark 日志(也看不到任何问题)。我将尝试更深入地分析它。该 avi 是使用海康威视相机的 VLC 捕获的。

Answer 1

我曾尝试使用 VLC MJPEG 服务器进行调试。这是问题所在。我的基于 gstreamer rtpjpegdepay 插件的客户端在直接连接到 Hikvision MJPEG 流时没有任何问题。所以大概是 VLC 错误或违反任何一方的标准。