Splitmuxsink creates files with wrong timestamp

Question

I am trying to create a simple rolling recorder with gstreamer using splitmuxsink.

std::string getTime() {
 std::time_t t = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
 std::tm ltime;
 localtime_r(&t, &ltime);
 std::ostringstream s;
 s << std::put_time(&ltime, "%H-%M-%S");
 return s.str();
}
gchararray cb_splitmuxsink_format_location(GstElement*, guint fragmentId, gpointer) {
 std::string name = std::string("segment-") + getTime() + ".mkv";
 LOG4CPLUS_INFO(log4cplus::Logger::getInstance(""), "Creating file " << name);
 return g_strdup(name.c_str());
}
int main(int argc, char** argv) {
 gst_init(&argc, &argv);
 log4cplus::initialize();
 log4cplus::BasicConfigurator::doConfigure();
 auto logger = log4cplus::Logger::getInstance("main");
 auto* pipeline = gst_parse_launch("rtspsrc location=rtsp://127.0.0.1:8554/test latency=0 ! \
 rtph264depay ! h264parse ! queue ! splitmuxsink name=\"splitmuxsink\" location=./segment%02d.mkv \
 max-size-bytes=6000000 muxer=matroskamux \
 muxer-properties=\"properties, streamable=true\"", NULL);
 if (!pipeline) {
 LOG4CPLUS_FATAL(logger, "Failed to create elements");
 return 1;
 }
 GstElement* splitmuxsink = gst_bin_get_by_name(GST_BIN(pipeline), "splitmuxsink");
 g_signal_connect(splitmuxsink, "format-location", G_CALLBACK(cb_splitmuxsink_format_location), NULL);
 GstStateChangeReturn ret = gst_element_set_state(pipeline, GST_STATE_PLAYING);
 if (ret == GST_STATE_CHANGE_FAILURE) {
 LOG4CPLUS_FATAL(logger, "Failed to start pipeline");
 return 1;
 }
 signal(SIGINT, intHandler);
 while (running) {
 }
 gst_element_set_state(pipeline, GST_STATE_NULL);
 gst_deinit();
 return 0;
}

I have an incoming stream with the time written on the video.
This will first create a segment-00-47-17.mkv which starts at the right time. But then I get a segment-00-47-47 which actually starts at 00-47-37, and every following segment is marked 10 seconds later.
I would point that the creation time of those files is also the one in their names and not the one in the video. Also increasing the segment durations with max-size-time still causes the same 10 seconds delay after the first split.

Does anyone know about this behaviour and on how to fix it?

• Alan Birtles: I'd guess some of the video is cached in memory before creating the file, I doubt there's much you can do about that

Answer 1

You are creating these timestamps yourself. You are just using the current system time. That does not take into account initial buffer times from starting the streams start playing. You are timestamping the files when the files are opened and not take any considerations of the stream. You should probably determine the stream time from the current running pipeline or timestamp of the last sample that has reached the sink.