mixer - Pygame Documentation

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pygame.mixer

pygame module for loading and playing sounds

pygame.mixer.init - initialize the mixer module | initialize the mixer module
pygame.mixer.pre_init - preset the mixer init arguments | preset the mixer init arguments
pygame.mixer.quit - uninitialize the mixer | uninitialize the mixer
pygame.mixer.get_init - test if the mixer is initialized | test if the mixer is initialized
pygame.mixer.stop - stop playback of all sound channels | stop playback of all sound channels
pygame.mixer.pause - temporarily stop playback of all sound channels | temporarily stop playback of all sound channels
pygame.mixer.unpause - resume paused playback of sound channels | resume paused playback of sound channels
pygame.mixer.fadeout - fade out the volume on all sounds before stopping | fade out the volume on all sounds before stopping
pygame.mixer.set_num_channels - set the total number of playback channels | set the total number of playback channels
pygame.mixer.get_num_channels - get the total number of playback channels | get the total number of playback channels
pygame.mixer.set_reserved - reserve channels from being automatically used | reserve channels from being automatically used
pygame.mixer.find_channel - find an unused channel | find an unused channel
pygame.mixer.get_busy - test if any sound is being mixed | test if any sound is being mixed
pygame.mixer.Sound - Create a new Sound object from a file | Create a new Sound object from a file
pygame.mixer.Channel - Create a Channel object for controlling playback | Create a Channel object for controlling playback

This module contains classes for loading Sound objects and controlling playback. The mixer module is optional and depends on SDL_mixer. Your program should test that `pygame.mixer` is available and intialized before using it.

The mixer module has a limited number of channels for playback of sounds. Usually programs tell pygame to start playing audio and it selects an available channel automatically. The default is 8 simultaneous channels, but complex programs can get more precise control over the number of channels and their use.

All sound playback is mixed in background threads. When you begin to play a Sound object, it will return immediately while the sound continues to play. `A` single Sound object can also be actively played back multiple times.

The mixer also has a special streaming channel. This is for music playback and is accessed through the `pygame.mixer.music` module.

The mixer module must be initialized like other pygame modules, but it has some extra conditions. The `pygame.mixer.init - initialize the mixer module` function takes several optional arguments to control the playback rate and sample size. Pygame will default to reasonable values, but pygame cannot perform Sound resampling, so the mixer should be initialized to match the values of your audio resources.

`NOTE:` Not to get less laggy sound, use a smaller buffer size. The default is set to reduce the chance of scratchy sounds on some computers. You can change the default buffer by calling `pygame.mixer.pre_init` before `pygame.mixer.init` or `pygame.init` is called. For example: `pygame.mixer.pre_init(44100,-16,2`, 1024) The default size was changed from 1024 to 3072 in pygame `1.8`.

pygame.mixer.init

initialize the mixer module
`pygame.mixer.init(frequency=22050, size=-16, channels=2, buffer=4096): return None`

Initialize the mixer module for Sound loading and playback. The default arguments can be overridden to provide specific audio mixing. Keyword arguments are accepted. For backward compatibility where an argument is set zero the default value is used (possible changed by a pre_init call).

The size argument represents how many bits are used for each audio sample. If the value is negative then signed sample values will be used. Positive values mean unsigned audio samples will be used. An invalid value raises an exception.

The channels argument is used to specify whether to use mono or stereo. 1 for mono and 2 for stereo. No other values are supported (negative values are treated as 1, values greater than 2 as 2).

The buffer argument controls the number of internal samples used in the sound mixer. The default value should work for most cases. It can be lowered to reduce latency, but sound dropout may occur. It can be raised to larger values to ensure playback never skips, but it will impose latency on sound playback. The buffer size must be a power of two (if not it is rounded up to the next nearest power of 2).

Some platforms require the `pygame.mixer` module to be initialized after the display modules have initialized. The top level `pygame.init - initialize all imported pygame modules` takes care of this automatically, but cannot pass any arguments to the mixer init. To solve this, mixer has a function `pygame.mixer.pre_init - preset the mixer init arguments` to set the proper defaults before the toplevel init is used.

It is safe to call this more than once, but after the mixer is initialized you cannot change the playback arguments without first calling `pygame.mixer.quit - uninitialize the mixer`.

pygame.mixer.pre_init

preset the mixer init arguments
`pygame.mixer.pre_init(frequency=22050, size=-16, channels=2, buffersize=4096): return None`

Call pre_init to change the defaults used when the real `pygame.mixer.init - initialize the mixer module` is called. Keyword arguments are accepted. The best way to set custom mixer playback values is to call `pygame.mixer.pre_init - preset the mixer init arguments` before calling the top level `pygame.init - initialize all imported pygame modules`. For backward compatibility argument values of zero is replaced with the startup defaults.

pygame.mixer.quit

uninitialize the mixer
`pygame.mixer.quit(): return None`

This will uninitialize `pygame.mixer`. All playback will stop and any loaded Sound objects may not be compatible with the mixer if it is reinitialized later.

pygame.mixer.get_init

test if the mixer is initialized
`pygame.mixer.get_init(): return (frequency, format, channels)`

If the mixer is initialized, this returns the playback arguments it is using. If the mixer has not been initialized this returns None

pygame.mixer.stop

stop playback of all sound channels
`pygame.mixer.stop(): return None`

This will stop all playback of all active mixer channels.

pygame.mixer.pause

temporarily stop playback of all sound channels
`pygame.mixer.pause(): return None`

This will temporarily stop all playback on the active mixer channels. The playback can later be resumed with `pygame.mixer.unpause - resume paused playback of sound channels`

pygame.mixer.unpause

resume paused playback of sound channels
`pygame.mixer.unpause(): return None`

This will resume all active sound channels after they have been paused.

pygame.mixer.fadeout

fade out the volume on all sounds before stopping
`pygame.mixer.fadeout(time): return None`

This will fade out the volume on all active channels over the time argument in milliseconds. After the sound is muted the playback will stop.

pygame.mixer.set_num_channels

set the total number of playback channels
`pygame.mixer.set_num_channels(count): return None`

Sets the number of available channels for the mixer. The default value is 8. The value can be increased or decreased. If the value is decreased, sounds playing on the truncated channels are stopped.

pygame.mixer.get_num_channels

get the total number of playback channels

Returns the number of currently active playback channels.

pygame.mixer.set_reserved

reserve channels from being automatically used
`pygame.mixer.set_reserved(count): return None`

The mixer can reserve any number of channels that will not be automatically selected for playback by Sounds. If sounds are currently playing on the reserved channels they will not be stopped.

This allows the application to reserve a specific number of channels for important sounds that must not be dropped or have a guaranteed channel to play on.

pygame.mixer.find_channel

find an unused channel
`pygame.mixer.find_channel(force=False): return Channel`

This will find and return an inactive Channel object. If there are no inactive Channels this function will return None. If there are no inactive channels and the force argument is True, this will find the Channel with the longest running Sound and return it.

If the mixer has reserved channels from `pygame.mixer.set_reserved - reserve channels from being automatically used` then those channels will not be returned here.

pygame.mixer.get_busy

test if any sound is being mixed
`pygame.mixer.get_busy(): return bool`

Returns True if the mixer is busy mixing any channels. If the mixer is idle then this return False.

pygame.mixer.Sound

Create a new Sound object from a file
`pygame.mixer.Sound(filename): return Sound`
`pygame.mixer.Sound(buffer): return Sound`
`pygame.mixer.Sound(object): return Sound`

Sound.play - begin sound playback | begin sound playback
Sound.stop - stop sound playback | stop sound playback
Sound.fadeout - stop sound playback after fading out | stop sound playback after fading out
Sound.set_volume - set the playback volume for this Sound | set the playback volume for this Sound
Sound.get_volume - get the playback volume | get the playback volume
Sound.get_num_channels - count how many times this Sound is playing | count how many times this Sound is playing
Sound.get_length - get the length of the Sound | get the length of the Sound
Sound.get_buffer - acquires a buffer object for the sameples of the Sound. | acquires a buffer object for the sameples of the Sound.

Load a new sound buffer from a filename, a python file object or a readable buffer object. Limited resampling will be performed to help the sample match the initialize arguments for the mixer.

The Sound object represents actual sound sample data. Methods that change the state of the Sound object will the all instances of the Sound playback.

The Sound can be loaded from an `OGG` audio file or from an uncompressed `WAV`.

Note: The buffer will be copied internally, no data will be shared between it and the Sound object.

`pygame.mixer.Sound(buffer)` is new in pygame `1.8`

Sound.play

begin sound playback
`Sound.play(loops=0, maxtime=0, fade_ms=0): return Channel`

Begin playback of the Sound `(i.e.`, on the computer's speakers) on an available Channel. This will forcibly select a Channel, so playback may cut off a currently playing sound if necessary.

The loops argument controls how many times the sample will be repeated after being played the first time. `A` value of 5 means that the sound will be played once, then repeated five times, and so is played a total of six times. The default value (zero) means the Sound is not repeated, and so is only played once. If loops is set to -1 the Sound will loop indefinitely (though you can still call stop() to stop it).

The maxtime argument can be used to stop playback after a given number of milliseconds.

The fade_ms argument will make the sound start playing at 0 volume and fade up to full volume over the time given. The sample may end before the fade-in is complete.

This returns the Channel object for the channel that was selected.

Sound.stop

stop sound playback
`Sound.stop(): return None`

This will stop the playback of this Sound on any active Channels.

Sound.fadeout

stop sound playback after fading out
`Sound.fadeout(time): return None`

This will stop playback of the sound after fading it out over the time argument in milliseconds. The Sound will fade and stop on all actively playing channels.

Sound.set_volume

set the playback volume for this Sound
`Sound.set_volume(value): return None`

This will set the playback volume (loudness) for this Sound. This will immediately affect the Sound if it is playing. It will also affect any future playback of this Sound. The argument is a value from `0.0` to `1.0`.

Sound.get_volume

get the playback volume
`Sound.get_volume(): return value`

Return a value from `0.0` to `1.0` representing the volume for this Sound.

Sound.get_num_channels

count how many times this Sound is playing
`Sound.get_num_channels(): return count`

Return the number of active channels this sound is playing on.

Sound.get_length

get the length of the Sound
`Sound.get_length(): return seconds`

Return the length of this Sound in seconds.

Sound.get_buffer

acquires a buffer object for the sameples of the Sound.
`Sound.get_buffer(): return BufferProxy`

Return a buffer object for the Sound samples. The buffer can be used for direct access and manipulation.

New in pygame `1.8`.

pygame.mixer.Channel

Create a Channel object for controlling playback
`pygame.mixer.Channel(id): return Channel`

Channel.play - play a Sound on a specific Channel | play a Sound on a specific Channel
Channel.stop - stop playback on a Channel | stop playback on a Channel
Channel.pause - temporarily stop playback of a channel | temporarily stop playback of a channel
Channel.unpause - resume pause playback of a channel | resume pause playback of a channel
Channel.fadeout - stop playback after fading channel out | stop playback after fading channel out
Channel.set_volume - set the volume of a playing channel | set the volume of a playing channel
Channel.get_volume - get the volume of the playing channel | get the volume of the playing channel
Channel.get_busy - check if the channel is active | check if the channel is active
Channel.get_sound - get the currently playing Sound | get the currently playing Sound
Channel.queue - queue a Sound object to follow the current | queue a Sound object to follow the current
Channel.get_queue - return any Sound that is queued | return any Sound that is queued
Channel.set_endevent - have the channel send an event when playback stops | have the channel send an event when playback stops
Channel.get_endevent - get the event a channel sends when playback stops | get the event a channel sends when playback stops

Return a Channel object for one of the current channels. The id must be a value from 0 to the value of `pygame.mixer.get_num_channels - get the total number of playback channels`.

The Channel object can be used to get fine control over the playback of Sounds. `A` channel can only playback a single Sound at time. Using channels is entirely optional since pygame can manage them by default.

Channel.play

play a Sound on a specific Channel
`Channel.play(Sound, loops=0, maxtime=0, fade_ms=0): return None`

This will begin playback of a Sound on a specific Channel. If the Channel is currently playing any other Sound it will be stopped.

The loops argument has the same meaning as in `Sound.play():` it is the number of times to repeat the sound after the first time. If it is 3, the sound will be played 4 times (the first time, then three more). If loops is -1 then the playback will repeat indefinitely.

As in `Sound.play - begin sound playback`, the maxtime argument can be used to stop playback of the Sound after a given number of milliseconds.

As in `Sound.play - begin sound playback`, the fade_ms argument can be used fade in the sound.

Channel.stop

stop playback on a Channel
`Channel.stop(): return None`

Stop sound playback on a channel. After playback is stopped the channel becomes available for new Sounds to play on it.

Channel.pause

temporarily stop playback of a channel
`Channel.pause(): return None`

Temporarily stop the playback of sound on a channel. It can be resumed at a later time with `Channel.unpause - resume pause playback of a channel`

Channel.unpause

resume pause playback of a channel
`Channel.unpause(): return None`

Resume the playback on a paused channel.

Channel.fadeout

stop playback after fading channel out
`Channel.fadeout(time): return None`

Stop playback of a channel after fading out the sound over the given time argument in milliseconds.

Channel.set_volume

set the volume of a playing channel
`Channel.set_volume(value): return None`
`Channel.set_volume(left, right): return None`

Set the volume (loudness) of a playing sound. When a channel starts to play its volume value is reset. This only affects the current sound. The value argument is between `0.0` and `1.0`.

If one argument is passed, it will be the volume of both speakers. If two arguments are passed and the mixer is in stereo mode, the first argument will be the volume of the left speaker and the second will be the volume of the right speaker. (If the second argument is None, the first argument will be the volume of both `speakers.)`

If the channel is playing a Sound on which set_volume() has also been called, both calls are taken into account. For example:

        sound = pygame.mixer.Sound("s.wav")
        channel = s.play()      # Sound plays at full volume by default
        sound.set_volume(0.9)   # Now plays at 90% of full volume.
        sound.set_volume(0.6)   # Now plays at 60% (previous value replaced).
        channel.set_volume(0.5) # Now plays at 30% (0.6 * 0.5).

Channel.get_volume

get the volume of the playing channel
`Channel.get_volume(): return value`

Return the volume of the channel for the current playing sound. This does not take into account stereo separation used by `Channel.set_volume`. The Sound object also has its own volume which is mixed with the channel.

Channel.get_busy

check if the channel is active
`Channel.get_busy(): return bool`

Returns true if the channel is activily mixing sound. If the channel is idle this returns False.

Channel.get_sound

get the currently playing Sound
`Channel.get_sound(): return Sound`

Return the actual Sound object currently playing on this channel. If the channel is idle None is returned.

Channel.queue

queue a Sound object to follow the current
`Channel.queue(Sound): return None`

When a Sound is queued on a Channel, it will begin playing immediately after the current Sound is finished. Each channel can only have a single Sound queued at a time. The queued Sound will only play if the current playback finished automatically. It is cleared on any other call to `Channel.stop - stop playback on a Channel` or `Channel.play - play a Sound on a specific Channel`.

If there is no sound actively playing on the Channel then the Sound will begin playing immediately.

Channel.get_queue

return any Sound that is queued
`Channel.get_queue(): return Sound`

If a Sound is already queued on this channel it will be returned. Once the queued sound begins playback it will no longer be on the queue.

Channel.set_endevent

have the channel send an event when playback stops
`Channel.set_endevent(): return None`
`Channel.set_endevent(type): return None`

When an endevent is set for a channel, it will send an event to the pygame queue every time a sound finishes playing on that channel (not just the first time). Use `pygame.event.get - get events from the queue` to retrieve the endevent once it's sent.

Note that if you called `Sound.play(n)` or `Channel.play(sound,n)`, the end event is sent only once: after the sound has been played "n+1" times (see the documentation of `Sound.play)`.

If `Channel.stop - stop playback on a Channel` or `Channel.play - play a Sound on a specific Channel` is called while the sound was still playing, the event will be posted immediately.

The type argument will be the event id sent to the queue. This can be any valid event type, but a good choice would be a value between `pygame.locals.USEREVENT` and `pygame.locals.NUMEVENTS`. If no type argument is given then the Channel will stop sending endevents.

Channel.get_endevent

get the event a channel sends when playback stops
`Channel.get_endevent(): return type`

Returns the event type to be sent every time the Channel finishes playback of a Sound. If there is no endevent the function returns `pygame.NOEVENT`.