Guile-GNOME: GStreamer version 0.9.92, updated 10 November 2007 Wim Taymans many others This manual is for (gnome gstreamer) (version 0.9.92, updated 10 November 2007) Copyright 2000-2007 Wim Taymans and others Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 2 or any later version published by the Free Software Foundation. i Short Contents 1 Overview :::::::::::::::::::::::::::::::::::::::::::: 1 2 GstBin :::::::::::::::::::::::::::::::::::::::::::::: 2 3 GstBuffer:::::::::::::::::::::::::::::::::::::::::::: 8 4 GstBus::::::::::::::::::::::::::::::::::::::::::::: 13 5 GstCaps:::::::::::::::::::::::::::::::::::::::::::: 18 6 GstChildProxy :::::::::::::::::::::::::::::::::::::: 24 7 GstClock ::::::::::::::::::::::::::::::::::::::::::: 26 8 gstconfig ::::::::::::::::::::::::::::::::::::::::::: 33 9 GstElementFactory ::::::::::::::::::::::::::::::::::: 34 10 GstElement ::::::::::::::::::::::::::::::::::::::::: 37 11 GstGError :::::::::::::::::::::::::::::::::::::::::: 53 12 GstEvent ::::::::::::::::::::::::::::::::::::::::::: 55 13 GstFilter ::::::::::::::::::::::::::::::::::::::::::: 63 14 GstFormat :::::::::::::::::::::::::::::::::::::::::: 64 15 GstGhostPad:::::::::::::::::::::::::::::::::::::::: 66 16 GstImplementsInterface ::::::::::::::::::::::::::::::: 68 17 GstIndexFactory ::::::::::::::::::::::::::::::::::::: 69 18 GstIndex ::::::::::::::::::::::::::::::::::::::::::: 70 19 GstInfo :::::::::::::::::::::::::::::::::::::::::::: 74 20 GstIterator ::::::::::::::::::::::::::::::::::::::::: 78 21 GstMessage ::::::::::::::::::::::::::::::::::::::::: 82 22 GstMiniObject :::::::::::::::::::::::::::::::::::::: 87 23 GstObject :::::::::::::::::::::::::::::::::::::::::: 88 24 GstPadTemplate ::::::::::::::::::::::::::::::::::::: 93 25 GstPad :::::::::::::::::::::::::::::::::::::::::::: 96 26 GstParse :::::::::::::::::::::::::::::::::::::::::: 115 27 GstPipeline :::::::::::::::::::::::::::::::::::::::: 116 28 GstPluginFeature ::::::::::::::::::::::::::::::::::: 121 29 GstPlugin ::::::::::::::::::::::::::::::::::::::::: 123 30 GstQuery :::::::::::::::::::::::::::::::::::::::::: 126 31 GstRegistry :::::::::::::::::::::::::::::::::::::::: 133 32 GstSegment :::::::::::::::::::::::::::::::::::::::: 138 33 GstStructure ::::::::::::::::::::::::::::::::::::::: 143 34 GstSystemClock :::::::::::::::::::::::::::::::::::: 150 35 GstTagList :::::::::::::::::::::::::::::::::::::::: 151 ii 36 GstTagSetter ::::::::::::::::::::::::::::::::::::::: 162 37 GstTask ::::::::::::::::::::::::::::::::::::::::::: 164 38 GstTrace :::::::::::::::::::::::::::::::::::::::::: 167 39 GstTypeFindFactory::::::::::::::::::::::::::::::::: 169 40 GstTypeFind ::::::::::::::::::::::::::::::::::::::: 171 41 GstUriHandler:::::::::::::::::::::::::::::::::::::: 173 42 GstUtils ::::::::::::::::::::::::::::::::::::::::::: 176 43 GstValue :::::::::::::::::::::::::::::::::::::::::: 177 44 GstVersion ::::::::::::::::::::::::::::::::::::::::: 178 45 Gst ::::::::::::::::::::::::::::::::::::::::::::::: 179 46 GstXML :::::::::::::::::::::::::::::::::::::::::: 183 Concept Index ::::::::::::::::::::::::::::::::::::::::: 186 Function Index ::::::::::::::::::::::::::::::::::::::::: 187 Chapter 1: Overview 1 1 Overview The GStreamer wrapper for Guile is a part of Guile-GNOME. Maybe write more here at some point. Chapter 2: GstBin 2 2 GstBin Base class and element that can contain other elements 2.1 Overview <gst-bin> is an element that can contain other <gst-element>, allowing them to be man- aged as a group. Pads from the child elements can be ghosted to the bin, see <gst-ghost- pad>. This makes the bin look like any other elements and enables creation of higher-level abstraction elements. A new <gst-bin> is created with gst-bin-new. Use a <gst-pipeline> instead if you want to create a toplevel bin because a normal bin doesn't have a bus or handle clock distribution of its own. After the bin has been created you will typically add elements to it with gst-bin-add. You can remove elements with gst-bin-remove. An element can be retrieved from a bin with gst-bin-get-by-name, using the elements name. gst-bin-get-by-name-recurse-up is mainly used for internal purposes and will query the parent bins when the element is not found in the current bin. An iterator of elements in a bin can be retrieved with gst-bin-iterate-elements. Various other iterators exist to retrieve the elements in a bin. gst-object-unref is used to drop your reference to the bin. The element-added signal is fired whenever a new element is added to the bin. Likewise the element-removed signal is fired whenever an element is removed from the bin. 2.2 Notes A <gst-bin> internally intercepts every <gst-message> posted by its children and imple- ments the following default behaviour for each of them: GST MESSAGE SEGMENT START GST MESSAGE SEGMENT DONE GST MESSAGE DURATION GST MESSAGE CLOCK LOST GST MESSAGE CLOCK PROVIDE OTHERS This message is only posted by sinks in the PLAYING state. If all sinks posted the EOS message, this bin will post and EOS message upwards. just collected and never forwarded upwards. The messages are used to decide when all elements have completed playback of their segment. Is posted by <gst-bin> when all elements that posted a SEGMENT START have posted a SEGMENT DONE. Is posted by an element that detected a change in the stream duration. The default bin behaviour is to clear any cached duration values so that the next duration query will perform a full duration recalculation. The duration change is posted to the application so that it can refetch the new duration with a duration query. Chapter 2: GstBin 3 This message is posted by an element when it can no longer provide a clock. The default bin behaviour is to check if the lost clock was the one provided by the bin. If so and the bin is currently in the PLAYING state, the message is forwarded to the bin parent. This message is also generated when a clock provider is removed from the bin. If this message is received by the application, it should PAUSE the pipeline and set it back to PLAYING to force a new clock distribution. This message is generated when an element can provide a clock. This mostly happens when a new clock provider is added to the bin. The default behaviour of the bin is to mark the currently selected clock as dirty, which will perform a clock recalculation the next time the bin is asked to provide a clock. This message is never sent tot the application but is forwarded to the parent of the bin. posted upwards. A <gst-bin> implements the following default behaviour for answering to a <gst- query:> GST QUERY POSITION OTHERS If the query has been asked before with the same format and the bin is a toplevel bin (ie. has no parent), use the cached previous value. If no previous value was cached, the query is sent to all sink elements in the bin and the MAXIMUM of all values is returned. If the bin is a toplevel bin the value is cached. If no sinks are available in the bin, the query fails. The query is sent to all sink elements in the bin and the MAXIMUM of all values is returned. If no sinks are available in the bin, the query fails. the query is forwarded to all sink elements, the result of the first sink that answers the query successfully is returned. If no sink is in the bin, the query fails. A <gst-bin> will by default forward any event sent to it to all sink elements. If all the sinks return TRUE, the bin will also return TRUE, else FALSE is returned. If no sinks are in the bin, the event handler will return TRUE. Last reviewed on 2006-04-28 (0.10.6) 2.3 Usage <gst-bin> [Class] This <gobject> class defines the following properties: async-handling The bin will handle Asynchronous state changes element-added (arg0 <gst-element>) [Signal on <gst-bin>] Will be emitted after the element was added to the bin. element-removed (arg0 <gst-element>) [Signal on <gst-bin>] Will be emitted after the element was removed from the bin. gst-bin-new (name mchars) ) (ret <gst-element>) [Function] Creates a new bin with the given name. name the name of the new bin Chapter 2: GstBin 4 ret a new <gst-bin> gst-bin-add (self <gst-bin>)(element <gst-element>) ) (ret bool) [Function] add [Method] Adds the given element to the bin. Sets the element's parent, and thus takes ownership of the element. An element can only be added to one bin. If the element's pads are linked to other pads, the pads will be unlinked before the element is added to the bin. MT safe. bin a <gst-bin> element the <gst-element> to add ret TRUE if the element could be added, FALSE if the bin does not want to accept the element. gst-bin-remove (self <gst-bin>)(element <gst-element>) [Function] ) (ret bool) remove [Method] Removes the element from the bin, unparenting it as well. Unparenting the element means that the element will be dereferenced, so if the bin holds the only reference to the element, the element will be freed in the process of removing it from the bin. If you want the element to still exist after removing, you need to call gst-object-ref before removing it from the bin. If the element's pads are linked to other pads, the pads will be unlinked before the element is removed from the bin. MT safe. bin a <gst-bin> element the <gst-element> to remove ret TRUE if the element could be removed, FALSE if the bin does not want to remove the element. gst-bin-get-by-name (self <gst-bin>)(name mchars) [Function] ) (ret <gst-element>) get-by-name [Method] Gets the element with the given name from a bin. This