How to manage delayed playbacks
Active DJ Studio allows setting up a list of sound files whose playback can be programmed to start after a given delay through a set of methods of the DelayedPlayback COM object.
Each sound file (item) can be added to the list of delayed playbacks in 2 different ways:
|•||by setting a specific amount of delay through the DelayedPlayback.ListAddItem or DelayedPlayback.ListAddItemEx methods|
|•||by setting a specific date and time through the DelayedPlayback.ListAddItemByDate or DelayedPlayback.ListAddItemByDateEx methods|
in both cases mentioned methods will return back a unique identifier that will be then used in order to access the item itself at a later stage.
The number of items inside the list can be enumerated through the DelayedPlayback.ListGetCount method.
If time positioning and duration of a certain item should overlap with the time positioning and duration of an existing item, you could decide if accepting or denying its insertion inside the list through the DelayedPlayback.AllowOverlapping property: if overlapping shouldn't be allowed, an ERR_DELAYED_PLAYBACK_OVERLAP error would be generated in case of overlapping. Note that, in case of overlapping, the playing song would be immediately stopped without any kind of fade-out when an overlapped song should be started.
As already mentioned, each item is identified through its unique identifier: this identifier is passed as a parameter for accessing the following item's related features:
|•||Get its duration through the DelayedPlayback.ItemGetDuration method|
|•||Start an immediate playback of the item through the DelayedPlayback.ItemPlayNow method with the option to keep it or remove it from the list|
|•||Set the effective range that will be played through the DelayedPlayback.ItemSetRange method: this range can be obtained through the DelayedPlayback.ItemGetRange method|
|•||Change or update the item's playback delay through the DelayedPlayback.ItemResetDelay method|
|•||Set the number of loops that will be performed on the given item through the DelayedPlayback.ItemSetLoopCount method: the number of loops can be obtained through the DelayedPlayback.ItemGetLoopCount method|
|•||Set the fade-in and fade-out time applied to start and end of playback through the DelayedPlayback.ItemSetFadeTime method: current fade-in and fade-out time can be obtained through the DelayedPlayback.ItemGetFadeTime method|
Delayed playbacks are mainly intended for usage with regular audio files so encrypted audio files and video clips are not supported directly. A possible trick for using encrypted audio files and video clips with delayed playback would be the following:
|•||Call DelayedPlayback.ListAddItem passing the index of the involved player and an empty pathname: this will force the player to start playback of its actual contents.|
As you may understand, with this trick there would be no possibility to add more than one single file to the list of delayed playbacks for the involved player.