--- a/gst_plugins_base/gst/playback/README Tue Aug 31 15:30:33 2010 +0300
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,91 +0,0 @@
-decodebin:
-
- A bin with a sinkpad that decodes the data into raw formats. It works by sending
- the input data through a typefind element and then recursively autoplugs elements
- from the registry until a raw format is obtained. It will then create a new ghostpad
- on itself to signal the app of the new pad.
-
- Decodebin will also remove pads when they are removed from the stream.
-
- TODO
- - reuse of decoderbin, cleanup in READY state
- - threading after demuxing?
- - new_media events should be handled.
- - caching of elements.
- - abstract more elements, pads (typefind, ...);
-
- The autoplugging happens as follows:
-
- 1) typefind is added internally to the bin.
- 2) the have_type signal is connected to typefind.
- 3) in the have_type callback the close_pad_link function is called
- 4) close_pad_link checks the type on the pad, if it is raw, a ghostpad
- is created and autoplugging for that pad stops.
- 5) if the type of the pad is not raw, a list of possible elements that
- can connect to this type is generated in find_compatibles.
- 6) try_to_link_1 with the element list is called. The function will loop
- over the element list and will try to connect one of the elements to
- the pad. If the link works, a call is made to close_link.
- 7) close_link loops over all the source pads of the element and
- recursively calls 4) for any ALWAYS pad. For elements with
- a SOMETIMES pad, a structure is set up and is passed to the callback
- of the new_pad signal.
- 8) in the new_pad callback, 4) is called to try to autoplug the
- new pad.
-
-
-playbasebin:
-
- A bin with an uri property. It will find the right source element from the registry
- and connect a decoderbin to it. When going to the PAUSED state, it will iterate the
- decoderbin and listen for new pad signals from it. It will connect a queue to each
- new pad and will iterate the decoderbin until one of the queues is filled. It is
- assumed that by that time all the streams will be found so that when leaving the
- PAUSED state, one can query the number of streams in the media file with the given
- uri.
-
- Playbasebin internally groups related streams together in a GstPlayBaseGroup. This
- is particulary important for chained oggs. Initially, a new group is created in
- the 'building' state. All new streams will be added to the building group until
- no-more-pads is signaled or one of the preroll queues overflows. When this happens,
- the group is commited to a list of groups ready for playback. PlaybaseBin will then
- attach a padprobe to each stream to figure out when it finished. It will remove
- the current group and install the next playable group, then.
-
- Before going to the PLAYING state, it is possible to connect a custom element to
- each of the streams. To do that, you have to add the element to the bin and then
- connect the pad(s) from the stream(s). You do not have to add the elements in
- a thread, the bin will take care of then when it's needed. You are allowed to use
- threads inside the elements, of course.
- The bin tries to be smart and doesn't add a queue when there is only one possible
- stream.
-
-
- TODO
- - reuse, cleanup in ready state
- - when the first pad is closed, it's possible that another dynamic element is
- added somewhere so that we need a queue for the first pad as well.
-
-
-playbin:
-
- Extends playbasebin, sets up default audiosink and videosink for first audio/video
- stream detected. implements seeking and querying on the configured sinks.
-
- It also waits for new notifications from playbasebin about any new groups that are
- becomming active. It then disconnects the sinks and reconnects them to the new
- pads in the group.
-
- TODO
- - reuse, refcounting, cleanup in READY state
- - be smarter about replugging the sinks instead of removing them and readding them.
- - Do not crap out when the audio device is in use.
-
-
-general
-
- TODO
- - playlist support. maybe use a playlist bin that streams the contents of the
- playlist on a pad, interleaved with new_media events. Also add a tuner
- interface while we're at it.
-