<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta name="Generator" content="Microsoft Word 14 (filtered medium)"> <style></style> </head> <body lang="EN-GB" link="blue" vlink="purple"> <div class="WordSection1"> Hi All.<o:p></o:p> I’m new to this list and GStreamer and would like some advice please.<o:p></o:p> I’ve been reading the GStreamer guide from http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/index.html and have written a couple of basic applications which have worked OK.<o:p></o:p> <o:p> </o:p> What I’d like to do is update my application, which currently reads a file and plays it, to give me access to a UYVY frame for each frame of the video.<o:p></o:p> <o:p> </o:p> See below for code snippets I’m using, which is mostly based on the playsink example given in chapter 20 of the guide, http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/section-components-playsink.html.<o:p></o:p> <o:p> </o:p> I’ve come across the video converter element which is able to output UYVY formatted video however I’m unsure how to link this in to my pipeline as it’s using a dynamic sink. The documentation for the videoconverter is here: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-plugins/html/gst-plugins-base-plugins-videoconvert.html<o:p></o:p> I’ve read this a number of times but am unsure how to link the extra element in and how to set the sink pad to be a UYVY format.<o:p></o:p> <o:p> </o:p> Once I’ve converted the video how do I get access to the frames? Is there a sink I can use to send the frames in to the application space or do I need to get access to the buffer? If so how?<o:p></o:p> <o:p> </o:p> Not that it should matter but I’m developing in c++ on windows.<o:p></o:p> Code:<o:p></o:p> … snip …<o:p></o:p> // Globals<o:p></o:p> GstElement *pipeline, *sink;<o:p></o:p> <o:p> </o:p> static void cb_pad_added (GstElement *dec, GstPad *pad, gpointer data)<o:p></o:p> { <o:p></o:p> GstCaps *caps;<o:p></o:p> GstStructure *str;<o:p></o:p> const gchar *name;<o:p></o:p> GstPadTemplate *templ;<o:p></o:p> GstElementClass *klass;<o:p></o:p> <o:p> </o:p> // check media type <o:p></o:p> caps = gst_pad_query_caps (pad, NULL);<o:p></o:p> str = gst_caps_get_structure (caps, 0);<o:p></o:p> name = gst_structure_get_name (str);<o:p></o:p> klass = GST_ELEMENT_GET_CLASS (sink);<o:p></o:p> if (g_str_has_prefix (name, "audio")) <o:p></o:p> {<o:p></o:p> templ = gst_element_class_get_pad_template (klass, "audio_sink");<o:p></o:p> }<o:p></o:p> else if (g_str_has_prefix (name, "video"))<o:p></o:p> {<o:p></o:p> templ = gst_element_class_get_pad_template (klass, "video_sink");<o:p></o:p> } <o:p></o:p> else if (g_str_has_prefix (name, "text"))<o:p></o:p> {<o:p></o:p> templ = gst_element_class_get_pad_template (klass, "text_sink");<o:p></o:p> }<o:p></o:p> else <o:p></o:p> { <o:p></o:p> templ = NULL;<o:p></o:p> }<o:p></o:p> if (templ)<o:p></o:p> {<o:p></o:p> GstPad *sinkpad;<o:p></o:p> sinkpad = gst_element_request_pad (sink, templ, NULL, NULL);<o:p></o:p> if (!gst_pad_is_linked (sinkpad))<o:p></o:p> {<o:p></o:p> gst_pad_link (pad, sinkpad);<o:p></o:p> }<o:p></o:p> gst_object_unref (sinkpad);<o:p></o:p> }<o:p></o:p> }<o:p></o:p> <o:p> </o:p> int main(int argc, char** argv)<o:p></o:p> {<o:p></o:p> .... snipped ....<o:p></o:p> <o:p> </o:p> // initialise gstreamer and get version information.<o:p></o:p> const gchar *nano_str;<o:p></o:p> guint major, minor, micro, nano;<o:p></o:p> gst_init(&argc, &argv);<o:p></o:p> <o:p> </o:p> // get the version of gstreamer.<o:p></o:p> gst_version(&major, &minor, &micro, &nano);<o:p></o:p> if (nano == 1)<o:p></o:p> {<o:p></o:p> nano_str = "(CVS)";<o:p></o:p> }<o:p></o:p> else if (nano == 2)<o:p></o:p> {<o:p></o:p> nano_str = "(Prerelease)";<o:p></o:p> }<o:p></o:p> else<o:p></o:p> { nano_str = "";<o:p></o:p> }<o:p></o:p> char cVersion[256];<o:p></o:p> sprintf(cVersion, "This program is linked against GStreamer %d.%d.%d %s",<o:p></o:p> major, minor, micro, nano_str);<o:p></o:p> print( cVersion );<o:p></o:p> <o:p> </o:p> GMainLoop *loop;<o:p></o:p> GstElement *dec;<o:p></o:p> GstBus *bus;<o:p></o:p> loop = g_main_loop_new (NULL, FALSE);<o:p></o:p> <o:p> </o:p> // setup <o:p></o:p> pipeline = gst_pipeline_new ("pipeline");<o:p></o:p> bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));<o:p></o:p> gst_bus_add_watch (bus, bus_call, loop);<o:p></o:p> gst_object_unref (bus);<o:p></o:p> <o:p> </o:p> dec = gst_element_factory_make ("uridecodebin", "source");<o:p></o:p> g_object_set (G_OBJECT (dec), "uri", argv[1],<o:p></o:p> NULL);<o:p></o:p> g_signal_connect (dec, "pad-added", G_CALLBACK (cb_pad_added), NULL);<o:p></o:p> <o:p> </o:p> // create audio output <o:p></o:p> sink = gst_element_factory_make ("playsink", "sink");<o:p></o:p> gst_util_set_object_arg (G_OBJECT (sink), "flags", <o:p></o:p> "soft-colorbalance+soft-volume+vis+text+audio+video");<o:p></o:p> gst_bin_add_many (GST_BIN (pipeline), dec, sink, NULL);<o:p></o:p> <o:p> </o:p> // run <o:p></o:p> gst_element_set_state (pipeline, GST_STATE_PLAYING);<o:p></o:p> g_main_loop_run (loop);<o:p></o:p> <o:p> </o:p> // cleanup <o:p></o:p> gst_element_set_state (pipeline, GST_STATE_NULL);<o:p></o:p> gst_object_unref (GST_OBJECT (pipeline));<o:p></o:p> <o:p> </o:p> print("all done.");<o:p></o:p> fclose( gLogFile );<o:p></o:p> gLogFile = NULL;<o:p></o:p> return 0;<o:p></o:p> }<o:p></o:p> … end of code. …<o:p></o:p> <o:p> </o:p> Thanks for any ideas and sorry for all the noddy questions.<o:p></o:p> Nick.<o:p></o:p> Nick Adamson<o:p></o:p> Software Engineer<o:p></o:p> <o:p> </o:p> </div> <div class="MsoNormal" style="text-align:center" align="center"> <hr size="2" width="100%" align="center"> </div> This email and any files attached are intended for the addressee and may contain information of a confidential nature. 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