Audio and Video Puzzles
These puzzles are used to load and play back audio and video files, as well as to synthesize MIDI sounds.
- Puzzles Reference
Loads an audio file using a specified URL. The audio is played via the HTML5 Audio tag or WebAudio API depending on the chosen type: music or sound/midi respectively. This puzzle also adds the loaded audio to a memory cache so that any subsequent uses of this puzzle with the same URL do not load the same sound file again. Using .mp3 format is recommended as it is supported by most web browsers.
Audio files take some time to load, so they are not available immediately. That's why simply using this puzzle inside the play puzzle may not work and the audio may not start playing.
In order to be sure that audio in your application works properly it's recommended to load audio files beforehand, for example, in the init tab which is executed before a Verge3D application is initialized. You can also use the connector puzzle to organize a bunch of "load sound" puzzles in a bit more convenient way:
After that using the preloaded audio files either in the main or user-created tabs won't cause any issues, since the audio is already cached after the first use of the "load sound" puzzle, hence it doesn't need to be downloaded again:
In general, audio playback initiated programmatically (as in the case of puzzles) will most likely be blocked by a browser. This happens due to autoplay policies that restrict how audio can be played automatically on a web page. The purpose of such restrictions is to stop web pages from making spontaneous noises or playing audio when it's not desired, thus improving overall user experience.
Although, such policies can be implemented differently in various browsers and also can have various conditions for allowing / not allowing autoplay, the general rule for playing audio is to wait for the user to interact with your web page.
In cases where such interaction is already implied by the application's logic, for example, playing a sound on click (be it either a 3d-object or an HTML button), those restrictions are not what you should worry about. But, let's say that you want your application to have some background music that starts playing when the app is loaded. Since that can not always be done in an automatic way, a good solution would be to make a "launch" button for starting the app when it's loaded and ready. Clicking it counts as a user interaction and allows to start audio playback.
"music" vs "sound" vs "midi" audio type
This puzzle allows you to choose which API to use for loading and playing audio files.
- music (default, HTML5 Audio tag) - should be used most of the time; suits better for long audio files, e.g. background music
sound (WebAudio API) - suits better for short audio files, e.g.
small sound effects; it's recommended to use this type only in the
- short looped (see the play puzzle and its loop option) sound effects - "sound" makes looped audio seamless, while with "music" you have a noticeable delay
- sound effects that should be played immediately, e.g. on user interaction, experience a delay on Safari - "sound" fixes this issue
- midi (WebAudio API + GM Synth) - special type of sound that used to play Standard MIDI files (with *.mid extension). Compared to music stored in *.mp3, MIDI files are really lightweight and have minimum impact on app loading time. The downside of using MIDI — somewhat reduced quality of soundtrack.
Web Audio API which is utilized by the sound and midi types is supported in most
modern browsers. However, if you need your audio to work in browsers with
no Web Audio support (e.g. Internet Explorer 11) you have to use the
If it's necessary to use the sound/music type in browsers where it is available and also support Internet Explorer 11 at the same time, then the recommended solution is to use the feature available puzzle with the Web Audio API option selected to check if the API is available or not and load audio with the music or the sound type depending on that. You can do that for both preloading and playing audio in a way shown below:
Creates an HTML5 video element and loads a sound file using a specified URL. This puzzle also adds the created video element to a memory cache so that any subsequent uses of this puzzle with the same URL do not load the same sound file again. Using .mp4 format is recommended as it is supported by most web browsers.
The load video puzzle does not create any visible elements on your scene. To make it visible, assign video texture to your materials using the replace texture puzzle.
Starts audio or video playback. The loop checkbox repeats playback if enabled.
Due to browser restrictions (preventing malicious websites from playing noisy sounds and videos) you should not execute this puzzle to play your assets automatically (upon scene loading). Instead, you should do this in some user-generated event. Use when clicked or event to handle such events.
There is one exception to this rule. Browsers allow playing muted videos automatically. See the mute puzzle.
Pauses audio or video playback.
Stops audio or video playback. Using this puzzle is equivalent to using the pause puzzle, followed by the rewind puzzle.
Makes the audio or video asset to play from the start.
set playback time
Set audio/video current playback time in seconds.
Setting playback time is not supported for sound (WebAudio) assets.
get playback time
Get audio/video current playback time in seconds.
Getting playback time is not supported for sound (WebAudio) assets.
set playback rate
Set audio/video playback rate. Specify value <1 to slow down playback, 1 for normal speed, and >1 to increase playback speed.
Setting playback rate is not supported for midi assets.
Sets the sound volume. Input volume is clamped to the 0.0-1.0 range. This puzzle also works for videos with embedded audio track.
Checks if a sound or video is being played back.
Mute a sound or video.
Apart from controlling audio volume, you can use this puzzle to start video playback automatically. This is possible, because web browsers allow playing muted videos without user interaction.
Unmute a sound or video.
Play sound using the built-in General MIDI-compatible software synthesizer (based on the TinySynth library). Various instruments and effects supported.
- note on
- Start to play note using the given synth channel with sound intensity specified as velocity (0-127). Use the at time value to specify playback starting time in seconds.
- note off
- Stop to play given note.
- set instrument
- Set channel instrument from the given list.
- set volume
- Set channel volume.
- set pan
- Set channel pan level.
- stop sounds
- Stop all sounds on the given channel.
To play drums, specify Drums as channel number and use the drum number to select instrument.
Return note number. Use it to pass notes to the 1-9 channel of the synth sound puzzle.
Octave numbers are specified using the scientific pitch notation, for example C 4 means middle C tone.
Return drum number. Use it to pass notes to the Drums channel of the synth sound puzzle.
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