Gstreamer appsink接收缓冲区比CARMA板上的实时缓冲区慢得多
Gstreamer appsink receiving buffers much slower than real time on CARMA board
我对询问堆栈溢出问题相对陌生,但我会尽我所能彻底解释这个问题。
我目前正在使用Axis IP摄像头获取CARMA板的实时视频。然后,GStreamer使用RTSP客户端获取这些帧,执行RTP分付款,然后对从相机发送的h.264图像进行解码。当我在我的电脑(目前配备了i7处理器)上执行这个过程时,没有延迟时间,流会实时输出到屏幕,以30Hz的速率更新。当我切换到我正在处理的CARMA板时,问题就出现了。appsink不是实时显示,而是以比正常慢得多的速率接收缓冲区。更具体地,当CARMA板上没有发生其他处理时,它仅以平均约10Hz的速率接收缓冲器,而不是以30Hz的速率来接收缓冲器。还应该注意的是,没有帧被丢弃;接收缓冲区的appsink正在接收所有缓冲区,但不是实时的。任何关于为什么会发生这种情况的见解都将不胜感激。我已经进行了检查,以确保时间戳也不是问题(即,如果我正在或没有使用GST时间戳,appsink接收缓冲区的速率不会改变)。CARMA委员会目前正在使用ubuntu 11.04并使用GCC进行编译。以下是一些代码片段及其各自的解释。
的一些定义
#define APPSINK_CAPS "video/x-raw-yuv,format=(fourcc)I420"
#define RTSP_URI "rtsp://(ipaddress)/axis-media/media.amp?videocodec=h264"
#define RTSP_LATENCY 0
#define RTSP_BUFFER_MODE 0
#define RTSP_RTP_BLOCKSIZE 65536
GStreamer管道设置代码:
/* Initialize GStreamer */
gst_init (&argc, &argv);
/* Create the elements */
data.rtspsrc = gst_element_factory_make("rtspsrc", NULL);
data.rtph264depay = gst_element_factory_make("rtph264depay", NULL);
data.nv_omx_h264dec = gst_element_factory_make("nv_omx_h264dec", NULL);
data.appsink = gst_element_factory_make("appsink", NULL);
if (!data.rtspsrc || !data.rtph264depay || !data.nv_omx_h264dec || !data.appsink) {
g_printerr ("Not all elements could be created.n");
return -1;
}
/* Set element properties */
g_object_set( data.rtspsrc, "location", RTSP_URI,
"latency", RTSP_LATENCY,
"buffer-mode", RTSP_BUFFER_MODE,
"rtp-blocksize", RTSP_RTP_BLOCKSIZE,
NULL);
g_object_set( data.rtph264depay, "byte-stream", FALSE, NULL);
g_object_set( data.nv_omx_h264dec, "use-timestamps", TRUE, NULL);
/* Configure appsink. This plugin will allow us to access buffer data */
GstCaps *appsink_caps;
appsink_caps = gst_caps_from_string (APPSINK_CAPS);
g_object_set (data.appsink, "emit-signals", TRUE,
"caps", appsink_caps,
NULL);
g_signal_connect (data.appsink, "new-buffer", G_CALLBACK (appsink_new_buffer), &data);
gst_caps_unref (appsink_caps);
/* Create the empty pipeline */
data.pipeline = gst_pipeline_new ("test-pipeline");
if (!data.pipeline) {
g_printerr ("Pipeline could not be created.");
}
/* Build the pipeline */
/* Note that we are NOT linking the source at this point. We will do it later. */
gst_bin_add_many (GST_BIN(data.pipeline),
data.rtspsrc,
data.rtph264depay,
data.nv_omx_h264dec,
data.appsink,
NULL);
if (gst_element_link (data.rtph264depay, data.nv_omx_h264dec) != TRUE) {
g_printerr ("rtph264depay and nv_omx_h264dec could not be linked.n");
gst_object_unref (data.pipeline);
return -1;
}
if (gst_element_link (data.nv_omx_h264dec, data.appsink) != TRUE) {
g_printerr ("nv_omx_h264dec and appsink could not be linked.n");
gst_object_unref (data.pipeline);
return -1;
}
/* Connect to the pad-added signal (CALLBACK!) */
g_signal_connect (data.rtspsrc, "pad-added", G_CALLBACK (pad_added_handler), &data);
/* Add a probe to perform hashing on H.264 bytestream */
GstPad *rtph264depay_src_pad = gst_element_get_static_pad (data.rtph264depay, "src");
(gulong) gst_pad_add_buffer_probe (rtph264depay_src_pad, G_CALLBACK (hash_and_report), (gpointer)(&data));
gst_object_unref (rtph264depay_src_pad); //unreference the source pad
/* Start playing */
ret = gst_element_set_state (data.pipeline, GST_STATE_PLAYING);
if (ret == GST_STATE_CHANGE_FAILURE) {
g_printerr ("Unable to set the pipeline to the playing state.n");
gst_object_unref (data.pipeline);
return -1;
}
/* Wait until error or EOS */
bus = gst_element_get_bus (data.pipeline);
do {
msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS));
/* Parse message */
if (msg != NULL) {
GError *err;
gchar *debug_info;
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_ERROR:
gst_message_parse_error (msg, &err, &debug_info);
g_printerr ("Error received from element %s: %sn", GST_OBJECT_NAME (msg->src), err->message);
g_printerr ("Debugging information: %sn", debug_info ? debug_info : "none");
g_clear_error (&err);
g_free (debug_info);
terminate = TRUE;
break;
case GST_MESSAGE_EOS:
g_print ("End-Of-stream reached.n");
break;
case GST_MESSAGE_STATE_CHANGED:
/* We are only interested in state-changed messages from the pipeline */
if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data.pipeline)) {
GstState old_state, new_state, pending_state;
gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
g_print ("Pipeline state changed from %s to %s:n", gst_element_state_get_name (old_state), gst_element_state_get_name (new_state));
}
break;
default:
//we should not reach here because we only asked for ERRORs and EOS and State Changes
g_printerr ("Unexpected message received.n");
break;
}
gst_message_unref (msg);
}
} while (!terminate);
现在pad_added_handler:
/* This function will be called by the pad-added signal */
//Thread 1
static void pad_added_handler (GstElement *src, GstPad *new_pad, CustomData *data) {
GstPad *sink_pad = gst_element_get_static_pad (data->rtph264depay, "sink");
GstPadLinkReturn ret;
GstCaps *new_pad_caps = NULL;
GstStructure *new_pad_struct = NULL;
const gchar *new_pad_type = NULL;
g_print ("Received new pad '%s' from '%s':n", GST_PAD_NAME (new_pad), GST_ELEMENT_NAME (src));
/* Check the new pad's type */
new_pad_caps = gst_pad_get_caps (new_pad);
new_pad_struct = gst_caps_get_structure (new_pad_caps, 0);
new_pad_type = gst_structure_get_name (new_pad_struct);
if (!g_str_has_prefix (new_pad_type, "application/x-rtp")) {
g_print (" It has type '%s' which is not RTP. Ignoring.n", new_pad_type);
goto exit;
}
/* If our converter is already linked, we have nothing to do here */
if (gst_pad_is_linked (sink_pad)) {
g_print (" We are already linked. Ignoring.n");
goto exit;
}
/* Attempt the link */
ret = gst_pad_link (new_pad, sink_pad);
if (GST_PAD_LINK_FAILED (ret)) {
g_print (" Type is '%s' but link failed.n", new_pad_type);
} else {
g_print (" Link succeeded (type '%s').n", new_pad_type);
}
exit:
/* Unreference the new pad's caps, if we got them */
if (new_pad_caps != NULL)
gst_caps_unref (new_pad_caps);
/* Unreference the sink pad */
gst_object_unref (sink_pad);
}
现在是每次appsink接收缓冲区时调用的appsink。这是我认为(尽管不确定)没有实时接收缓冲区的功能,这让我相信我正在做的某种处理导致在处理另一个缓冲区之前过了太多时间:
// Called when appsink receives a buffer: Thread 1
void appsink_new_buffer (GstElement *sink, CustomData *data) {
GstBuffer *buffer;
/* Retrieve the buffer */
g_signal_emit_by_name (sink, "pull-buffer", &buffer);
if (buffer) {
(((CustomData*)data)->appsink_buffer_count)++;
//push buffer onto queue, to be processed in different thread
if (GstBufferQueue->size() > GSTBUFFERQUEUE_SIZE) {
//error message
printf ("GstBufferQueue is full!n");
//release buffer
gst_buffer_unref (buffer);
} else {
//push onto queue
GstBufferQueue->push(buffer);
//activate thread
connectionDataAvailable_GstBufferQueue.notify_all();
}
}
}
我正在使用的相机链接:
http://www.axis.com/products/cam_p1357/index.htm
希望这能有所帮助。我将继续自己调查这个问题,并在他们到来时提供更新。如果你需要任何其他信息,请告诉我,我期待着阅读你的回复!
感谢
所以问题显然不是程序(即软件设计),而是CARMA板上的硬件组件无法跟上我正在做的处理量。换句话说,CARMA上的Tegra 3处理器作为一个设备是不够的。可能的解决方案是减少我在CARMA板上进行的处理,或者升级到不同的板。我希望这能帮助人们理解小型设备上可用的有限处理,同时也能意识到处理器(特别是实现片上系统模型的Tegra 3)目前可能不具备跟上需要大型实时计算的项目或系统所需的计算能力。
简而言之,买东西要小心!尽最大努力确保您购买的产品适合项目!话虽如此,但不要害怕尝试新设备。尽管我不能做我想做的事,但我学到了比我预想的更多的东西。毕竟,计算机科学只是不断学习:p
是的,这是一篇已有九年历史的帖子。
然而,公认的答案(OP)错误地认为他们的Tegra soc没有足够的处理能力。
应该建议未来的读者,只要做一些小的更改,这项任务在嵌入式系统上是可行的。
此代码有两个问题。
- 管道没有得到优化,也没有像应该的那样使用队列。queue元素允许您在线程之间拆分基本任务。看起来应该是这样的
rtsprc->rtph264日->h264解析->队列->解码器->队列->appsink
- 我们不知道GstBufferQueue是什么,因为OP从未共享过它。然而,由于它在一个单独的线程中消耗数据,队列可能会阻止生产者线程(appsink_new_buffer)向其推送更多数据。因此,导致管道速度显著减慢,因为回调需要等待队列解锁,然后才能将缓冲区推送到队列并返回到管道
未来的读者,为了克服这个问题2,我建议使用环形缓冲区。这将允许您在不中断管道的情况下连续推送新的样本/缓冲区。
- C++字符*缓冲区的大小
- 为什么msgrcv()将垃圾字符馈送到缓冲区
- 使用动态分配的数组会导致代码分析发出虚假的C6386缓冲区溢出警告
- ostream过载时的缓冲区冲洗
- C++中的高效循环缓冲区,它将被传递给C样式数组函数参数
- Xaudio2在更改缓冲区或循环时弹出声音
- 为什么我在leetcode上收到AddressSanitizer:地址0x602000000058上的堆缓冲区溢出错误
- 如何将图像传输到c++(dll)中的缓冲区,然后在c#的缓冲区中读/写
- 如何在cpp.中使用协议缓冲区存储大缓冲区/数组(char/int)
- 多线程双缓冲区
- 从数据库实时显示QT c++中的数据
- Android P-9.0.0_r53 Logcat主缓冲区超出定义大小
- 套接字读取后,我在缓冲区中看到意外输入
- std::带有自定义缓冲区的 iostream 不允许我写入
- Qt是否能够支持小缓冲区低延迟视频应用(例如实时流)
- Gstreamer appsink接收缓冲区比CARMA板上的实时缓冲区慢得多
- 缓冲区中的实时数据存储@Visual Studio 2013 Professional C++Windows 7
- 为什么getchar像缓冲区一样工作,而不是像预期的那样实时工作?
- 实时音频,快速循环中的临时缓冲区,不同的方法
- OpenGL和C++:实时处理和绑定缓冲区