<div dir="ltr"><div>I have created a test pipeline (see code below) using a custom appsrc that creates an h264 stream and sends over rtp.</div><div> </div><div>I am testing it with the following command line to receive and play the video stream:</div><div>gst-launch-1.0 -v udpsrc port=5000 caps = "application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! rtph264depay ! decodebin ! videoconvert ! autovideosink</div><div> </div><div>The command-line inside the application looks like this:</div><div>appsrc name=MyAppSrc ! video/x-raw,width=640,height=360,framerate=10/1 ! videoconvert ! identity name=ident ! x264enc zerolatency=true speed-preset=superfast ! rtph264pay ! udpsink host=127.0.0.1 port=5000</div><div> </div><div>At the moment the appsrc is generating frames at precisely 10fps and I set the buffer timestamps correctly. However, unless I also specify the framerate (in the caps string following the appsrc) as 10/1 the client viewer constantly complains of:</div><div>WARNING: from element /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstD3D11VideoSinkBin:autovideosink0-actual-sink-d3d11video/GstD3D11VideoSink:d3d11videosink0: A lot of buffers are being dropped. Additional debug info: ../libs/gst/base/gstbasesink.c(3134): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstD3D11VideoSinkBin:autovideosink0-actual-sink-d3d11video/GstD3D11VideoSink:d3d11videosink0: There may be a timestamping problem, or this computer is too slow.</div><div> </div><div> </div><div>The problem is:</div><div>In the real application, the appsrc will produce frames at a variable rate - between about 2 and 20 fps. How can I get this to work if I'm required to set a fixed framerate?</div><div> </div><div>Provided the buffer timestamps are set, why does the framerate property have any bearing on the pipeine?</div><div> </div><div>Here is the application code:</div><div> </div><div>// NativeBasicPipeline.cpp : This file contains the 'main' function. Program execution begins and ends there. // #include <gst/gst.h> #include <gst/app/gstappsrc.h> GTimer* timer; GstAppSrc* appSrc; guint sourceid = 0; int width = 1; int colour = 255; bool read_data() { static GstClockTime time = 0; static guint64 offset = 0; GstFlowReturn ret; auto ms = g_timer_elapsed(timer, NULL); if (ms > 1.0 / 10.0) { auto size = 640 * 3 * 360; gpointer copy = g_malloc(size); memset(copy, colour % 255, size); colour += 10; GstBuffer* buffer = gst_buffer_new_wrapped(copy, size); //GST_BUFFER_TIMESTAMP(buffer) = pts; GST_BUFFER_PTS(buffer) = time; GST_BUFFER_DTS(buffer) = time; GST_BUFFER_DURATION(buffer) = 100 * GST_MSECOND; GST_BUFFER_OFFSET(buffer) = offset++; GST_BUFFER_OFFSET_END(buffer) = offset; time += 100 * GST_MSECOND; g_signal_emit_by_name(appSrc, "push-buffer", buffer, &ret); //ret = gst_app_src_push_buffer(appSrc, buffer); gst_buffer_unref(buffer); g_timer_start(timer); return TRUE; } return TRUE; } void start_feed(GstElement* pipeline, guint size, void* unused) { if (sourceid == 0) { sourceid = g_idle_add((GSourceFunc)read_data, 0); } } void stop_feed(GstElement* pipeline, void* unused) { if (sourceid != 0) { g_source_remove(sourceid); sourceid = 0; } } static gboolean print_field(GQuark field, const GValue* value, gpointer pfx) { gchar* str = gst_value_serialize(value); g_print("%s %15s: %s\n", (gchar*)pfx, g_quark_to_string(field), str); g_free(str); return TRUE; } static void print_caps(const GstCaps* caps, const gchar* pfx) { guint i; g_return_if_fail(caps != NULL); if (gst_caps_is_any(caps)) { g_print("%sANY\n", pfx); return; } if (gst_caps_is_empty(caps)) { g_print("%sEMPTY\n", pfx); return; } for (i = 0; i < gst_caps_get_size(caps); i++) { GstStructure* structure = gst_caps_get_structure(caps, i); g_print("%s%s\n", pfx, gst_structure_get_name(structure)); gst_structure_foreach(structure, print_field, (gpointer)pfx); } } void handoff(GstElement* pipeline, GstBuffer* buffer, void* unused) { static int count = 0; static GstBuffer* buffers[50]; //auto ident = gst_bin_get_by_name(GST_BIN(pipeline), "ident"); auto pads = GST_ELEMENT_PADS(pipeline); auto pad0 = GST_PAD(pads->data); auto pad1 = GST_PAD(pads->next->data); auto caps = gst_pad_get_current_caps(pad1); print_caps(caps, ""); if (count < 50) { GstBuffer* copy = gst_buffer_copy(buffer); buffers[count] = copy; ++count; } else { count = 100; } } int main() { GstElement* pipeline; GstBus* bus; GstMessage* msg; timer = g_timer_new(); /* Initialize GStreamer */ gst_init(0, 0); /* Build the pipeline */ GError* err = 0; //auto udpPipe = "videotestsrc pattern=smpte ! video/x-raw,width=640,height=360,framerate=10/1 ! videoscale ! videoconvert ! identity name=ident ! x264enc zerolatency=true speed-preset=superfast ! rtph264pay ! udpsink host=127.0.0.1 port=5000"; //auto videoPipe = "videotestsrc pattern=smpte ! video/x-raw,width=640,height=360,framerate=10/1 ! videoscale ! videoconvert ! autovideosink"; auto appSrcPipe = "appsrc name=MyAppSrc ! video/x-raw,width=640,height=360 ! videoconvert ! identity name=ident ! x264enc zerolatency=true speed-preset=superfast ! rtph264pay ! udpsink host=127.0.0.1 port=5000"; //auto appSrcPipeVideo = "appsrc name=MyAppSrc ! videoscale ! videoconvert ! autovideosink"; pipeline = gst_parse_launch (appSrcPipe, &err); appSrc = (GstAppSrc*)gst_bin_get_by_name(GST_BIN(pipeline), "MyAppSrc"); g_object_set(G_OBJECT(appSrc), "format", GST_FORMAT_TIME, NULL); g_signal_connect(appSrc, "need-data", G_CALLBACK(start_feed), 0); g_signal_connect(appSrc, "enough-data", G_CALLBACK(stop_feed), 0); auto caps = gst_caps_new_simple("video/x-raw", "format", G_TYPE_STRING, "RGB", "bpp", G_TYPE_INT, 24, "depth", G_TYPE_INT, 24, "width", G_TYPE_INT, 640, "height", G_TYPE_INT, 360, NULL); gst_app_src_set_caps((GstAppSrc*)appSrc, caps); //GstPad* pad = gst_element_get_static_pad(appSrc, "src"); //auto ident = gst_bin_get_by_name(GST_BIN(pipeline), "ident"); //g_signal_connect(ident, "handoff", G_CALLBACK(handoff), 0); /* Start playing */ gst_element_set_state(pipeline, GST_STATE_PLAYING); auto main_loop = g_main_loop_new(NULL, FALSE); g_main_loop_run(main_loop); /* Wait until error or EOS */ bus = gst_element_get_bus(pipeline); msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_ERROR | GST_MESSAGE_EOS)); /* Free resources */ if (msg != NULL) gst_message_unref(msg); gst_object_unref(bus); gst_element_set_state(pipeline, GST_STATE_NULL); gst_object_unref(pipeline); return 0; } </div></div>