x264enc and variable rate appsrc

Nicolas Dufresne nicolas at ndufresne.ca
Tue Sep 22 14:21:25 UTC 2020


Le mardi 22 septembre 2020 à 12:34 +0100, David J a écrit :
> Thanks! I like a simple fix.... autovideosink sync=false fixed it!

sync=false might cause runner effects on stutter, just be aware, it
depends on the level of "smoothness" you are looking for.

> 
> FYI I had tried framerate 0/1 - I think this is the default if you don't set anything manually
> 
> On Tue, 22 Sep 2020 at 12:27, Gary Metalle <Gary.Metalle at rvl.co.uk> wrote:
> > Hi
> > 
> > 
> > What happens if you use a framerate of 0/1? This is the way to define a variable framerate.
> > 
> > 
> > 
> > Maybe the issue is with your decoder pipeline and the not the encoding. Have you tried setting 'sync=FALSE' for the video sink you're using?
> > 
> > From: gstreamer-devel <gstreamer-devel-bounces at lists.freedesktop.org> on behalf of David J <davywj at gmail.com>
> > Sent: 22 September 2020 12:21
> > To: Discussion of the development of and with GStreamer
> > Subject: x264enc and variable rate appsrc
> >  
> > I have created a test pipeline (see code below) using a custom appsrc that creates an h264 stream and sends over rtp.
> > 
> > I am testing it with the following command line to receive and play the video stream:
> > 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
> > 
> > The command-line inside the application looks like this:
> > 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
> > 
> > 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:
> > 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.
> > 
> > 
> > The problem is:
> > 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?
> > 
> > Provided the buffer timestamps are set, why does the framerate property have any bearing on the pipeine?
> > 
> > Here is the application code:
> > 
> > // 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;
> > }
> > 
> > 
> > _______________________________________________
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> > gstreamer-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> 
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