93 lines
2.9 KiB
Plaintext
93 lines
2.9 KiB
Plaintext
== Files ==
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ocarina/include/
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audio.h
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ocarina/lib/
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audio.cpp
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== Depends ==
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deck library
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Audio: (lib/audio.cpp)
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This file will introduce an "audio" namespace containing all of the
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functions interacting with gstreamer. This will create a wrapper
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namespace that will be easier to work with than using raw gstreamer
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functions.
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The audio layer is meant to be an interface used by the front end to
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control most features of the backend library. This means implementing
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next track, previous track, and so on here.
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Gstreamer options passed to audio :: init() can be found by running
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`gst-inspect-1.0 --help-gst` on the command line.
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- Internal:
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Set up a message bus to look for end-of-stream and error messages so
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the next song can be played. This function should call the play
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function after loading a track and after checking the "pause after N"
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count.
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- API:
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void audio :: init(argc, argv)
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Initialize the gstreamer layer and reload the track that was
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last loaded before shutdown. Gstreamer is supposed to remove
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options from the argv array as they are processed, so pass
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pointers to argc and argv to this function.
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void audio :: quit()
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Clean up memory allocated by gstreamer.
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bool audio :: play()
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bool audio :: pause()
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Change the gstreamer state to either GST_STATE_PLAYING or
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GST_STATE_PAUSED. Return true on success and false otherwise.
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bool audio :: seek_to(long)
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Seek to a position X nanoseconds into the track. Return true
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if track is loaded and the seek isn't out of bounds. False
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otherwise.
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Seconds can be converted to nanoseconds by multiplying with
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GST_SECOND.
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void audio :: stop()
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pause()
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seek_to(0)
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bool audio :: next()
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Call the deck :: next() function to get the next trackid,
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and load that file into the gstreamer pipeline. Do not change
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the state of the pipeline (if nothing is playing yet, don't
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call play()). Return true if a track has been loaded into the
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pipeline, false otherwise.
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void audio :: previous()
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Call the playlist :: previous() function to iterate backwards
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through the recently played playlist. Load the returned trackid
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without changing the pipeline state.
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trackid audio :: current_trackid()
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Return the trackid of the currently playing song.
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unsigned int audio :: position()
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Return the number of seconds that the song has played.
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unsigned int audio :: duration()
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Return the duration of the current song in seconds.
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void audio :: pause_after(bool enabled, unsigned int N)
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Pause after N tracks. The first parameter is a bool
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representing if this feature is enabled or not (true == enabled,
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false == disabled).
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The count will only be decremented when an end-of-stream message
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is received by the gstreamer pipeline, and not when calling
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next().
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bool audio :: pause_enabled()
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Return true if pausing is enabled, and false if pausing is
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disabled.
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unsigned int audio :: pause_count()
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Return the number of tracks that will be played before
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playback pauses.
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