/usr/share/psychtoolbox-3/PsychDemos/BasicSoundScheduleDemo.m is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
This file is owned by root:root, with mode 0o644.
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% BasicSoundScheduleDemo([wavfilenames])
%
% This demo shows two things:
%
% - How to use audio schedules in PsychPortAudio to preprogram a sequence
% of different sounds to play and how to dynamically add new sounds to the
% schedule while it is playing. This is similar to "playlists" in typical
% audio player applications like iTunes or the iPod etc.
%
% - How to create and use many prefilled audio buffers before start of a
% session. This way you can preload all needed sounds before start of an
% experiment into memory, in a format optimized for fast playback and low
% memory usage. This is similar to the concept of textures or offscreen
% windows in the domain of Screen() for the visuals.
%
%
%
% Optional arguments:
%
% wavfilenames = Name of a .wav sound file to load and play back, or a cell
% array with multiple filenames to load. Otherwise the default sound files
% provided with Psychtoolbox will be loaded.
%
% The demo first loads all soundfiles, and resamples them to identical
% samplingrate if possible. Then it plays the first second of each of them.
% Then it goes into an interactive mode: By pressing any of the F1 - F10
% keys or any letter key, you can select a specific file for playback. By
% pressing any other key you exit the interactive loop. After the
% interactive loop has finished, a subset of the soundfiles is played again
% with a different method, for about 3 repetitions. Then the demo exits.
%
% History:
% 04/09/2009 mk Written.
% Running on PTB-3? Abort otherwise.
AssertOpenGL;
% Establish mapping of keys for the interactive loop:
KbName('UnifyKeyNames');
for i=1:10
key(i) = KbName(sprintf('F%i', i)); %#ok<AGROW>
end
for i=11:11+25
key(i) = KbName(sprintf('%s', char('a' + i - 11))); %#ok<AGROW>
end
keyspace = KbName('space');
% Filenames provided?
if nargin < 1
wavfilenames = [];
end
if isempty(wavfilenames)
% No sound file provided. Load our standard sounds:
sounddir = [ PsychtoolboxRoot 'PsychDemos' filesep 'SoundFiles' filesep ];
% Ok, on MK's machine we have a special treat ;-)
if exist([PsychHomeDir 'Music/StarTrekSounds/'], 'dir')
sounddir = [ PsychHomeDir 'Music/StarTrekSounds/' ];
end
infilenames = dir( [ sounddir '*.wav' ] );
infilenames.name;
for i=1:length(infilenames)
wavfilenames{i} = [ sounddir infilenames(i).name ];
end
end
nfiles = length(wavfilenames);
% Always init to 2 channels, for the sake of simplicity:
nrchannels = 2;
% Does a function for resampling exist?
if exist('resample') %#ok<EXIST>
% Yes: Select a target sampling rate of 44100 Hz, resample if
% neccessary:
freq = 44100;
doresample = 1;
else
% No. We will choose the frequency of the wav file with the highest
% frequency for actual playback. Wav files with deviating frequencies
% will play too fast or too slow, b'cause we can't resample:
% Init freq:
freq = 0;
doresample = 0;
end
% Perform basic initialization of the sound driver:
InitializePsychSound(1);
% Read all sound files and create & fill one dynamic audiobuffer for
% each read soundfile:
buffer = [];
j = 0;
for i=1:nfiles
try
% Make sure we don't abort if we encounter an unreadable sound
% file. This is achieved by the try-catch clauses...
[audiodata, infreq] = wavread(char(wavfilenames(i)));
dontskip = 1;
catch
fprintf('Failed to read and add file %s. Skipped.\n', char(wavfilenames(i)));
dontskip = 0;
psychlasterror
psychlasterror('reset');
end
if dontskip
j = j + 1;
if doresample
% Resampling supported. Check if needed:
if infreq ~= freq
% Need to resample this to target frequency 'freq':
fprintf('Resampling from %i Hz to %i Hz... ', infreq, freq);
audiodata = resample(audiodata, freq, infreq);
end
else
% Resampling not supported by Matlab/Octave version:
% Adapt final playout frequency to maximum frequency found, and
% hope that all files match...
freq = max(infreq, freq);
end
[samplecount, ninchannels] = size(audiodata);
audiodata = repmat(transpose(audiodata), nrchannels / ninchannels, 1);
buffer(end+1) = PsychPortAudio('CreateBuffer', [], audiodata); %#ok<AGROW>
[fpath, fname] = fileparts(char(wavfilenames(j)));
fprintf('Filling audiobuffer handle %i with soundfile %s ...\n', buffer(j), fname);
end
end
% Recompute number of available sounds:
nfiles = length(buffer);
% Open the default audio device [], with default mode [] (==Only playback),
% and a required latencyclass of 1 == standard low-latency mode, as well as
% a playback frequency of 'freq' and 'nrchannels' sound output channels.
% This returns a handle 'pahandle' to the audio device:
pahandle = PsychPortAudio('Open', [], [], 1, freq, nrchannels);
% For the fun of demoing this as well, we switch PsychPortAudio to runMode
% 1, instead of the default runMode 0. This will slightly increase the cpu
% load and general system load, but provide better timing and even lower
% sound onset latencies under certain conditions. It is not really needed
% in this demo, just here to grab your attention for this feature. Type
% PsychPortAudio RunMode? for more details...
runMode = 1;
PsychPortAudio('RunMode', pahandle, runMode);
% Enable use of sound schedules: We create a schedule of default size,
% currently 128 slots by default. From now on, the driver will not play
% back the sounds stored via PsychPortAudio('FillBuffer') anymore. Instead
% you'll have to define a "playlist" or schedule via subsequent calls to
% PsychPortAudio('AddToSchedule'). Then the driver will process that
% schedule by playing all defined sounds in the schedule, one after each
% other, until the end of the schedule is reached. You can add new items to
% the schedule while the schedule is already playing.
PsychPortAudio('UseSchedule', pahandle, 1);
% Build an initial play sequence. Play each buffer once for a starter:
for i=1:nfiles
% Play buffer(i) from startSample 0.0 seconds to endSample 1.0
% seconds. Play one repetition of each soundbuffer...
PsychPortAudio('AddToSchedule', pahandle, buffer(i), 1, 0.0, 1.0, 1);
end
fprintf('\nReady. Press any key to start...\n\n\n');
% Wait for single keystroke:
KbStrokeWait;
% Start audio playback of the defined schedule. We don't spec the
% 'repetitions' parameter, as this parameter is ignored when using sound
% schedules. To repeat a schedule, you must refill it in time with new
% slots or select its size so it auto-repeats properly. Why this restriction?
% As a safety measure against programming errors. Without this, it would be
% easy to create infinite playback loops due to small programming mistakes,
% where you can't exit sond playback anymore and have to kill Matlab/Octave
% just to get your system back. This restriction may be lifted in future
% driver releases if we find a good way to implement some child-protection.
%
% Start playback immediately (0) and wait for the playback to start:
PsychPortAudio('Start', pahandle, [], 0, 1);
fprintf('Audio playback started: Press key F1 to F10 or any letter key for a sound, any other key to quit.\n');
% Stay in a little interactive loop:
notprinted = 1;
while 1
% Query current playback status:
s = PsychPortAudio('GetStatus', pahandle);
% Keyboard input?
[down, secs, keyCode] = KbCheck;
if down
% Yes. Respond to it:
kc = min(find(keyCode)); %#ok<MXFND>
kc = find(key == kc);
if ~isempty(kc)
% A key in array 'key' pressed (F1 to F10 or a letter key).
% Map it to a audio buffer handle:
kc = mod(kc - 1, nfiles) + 1;
fprintf('KEY %s pressed: Playing buffer %i\n', KbName(min(find(keyCode))), buffer(kc)); %#ok<MXFND>
KbReleaseWait;
% Engine still running on a schedule?
if s.Active == 0
% Schedule finished, engine stopped. Before adding new
% slots we first must delete the old ones, ie., reset the
% schedule:
PsychPortAudio('UseSchedule', pahandle, 2);
end
% Add new slot with playback request for user-selected buffer
% to a still running or stopped and reset empty schedule. This
% time we select one repetition of the full soundbuffer:
PsychPortAudio('AddToSchedule', pahandle, buffer(kc), 1, 0, [], 1);
% If engine has stopped, we need to restart:
if s.Active == 0
PsychPortAudio('Start', pahandle, [], 0, 1);
notprinted = 1;
end
else
% Space key pressed and engine stopped?
if keyCode(keyspace) && (s.Active == 0)
% Reset schedule to ready state, and restart sound playback of
% the whole current schedule:
PsychPortAudio('UseSchedule', pahandle, 3);
PsychPortAudio('Start', pahandle, [], 0, 1);
notprinted = 1;
KbReleaseWait;
else
% Other (unknown) key pressed: Finish interactive loop.
break;
end
end
else
% No key pressed. Give some feedback to user:
if (s.Active == 0) && (notprinted == 1)
fprintf('Audio playback paused: Press key F1 to F10 or any letter key for a sound, SPACE for replay, or any other key to quit.\n');
notprinted = 0;
end
end
% Wait a bit before next status and key query. The 'YieldSecs' option
% tells WaitSecs that this wait doesn't need to be accurate down to the
% millisecond, but allows for some lenience in timing. This slack
% allows to reduce system load:
WaitSecs('YieldSecs', 0.05);
end
% End of interactive loop.
% Stop playback: Stop immediately, but wait for stop to happen:
PsychPortAudio('Stop', pahandle, 0, 1);
% Another little demo application of audio buffers, now non-interactive:
fprintf('\n\nFillBuffer test: Using multibuffers without schedule, but as sources for streaming refill...\n');
% Disable and delete schedule: Back to standard single playbuffer operation,
% where one can only specify sounds for playback by 'FillBuffer' or
% 'RefillBuffer' commands to fill the single default playback buffer:
PsychPortAudio('UseSchedule', pahandle, 0);
% Fill playbuffer with content of buffer(1):
PsychPortAudio('FillBuffer', pahandle, buffer(1));
% Start playback in 2 seconds from now, 4 repetitions, wait for start:
PsychPortAudio('Start', pahandle, 4, GetSecs + 2, 1);
% Streaming refill with content of buffer(2). Append the content to the
% currently playing sound stream:
PsychPortAudio('FillBuffer', pahandle, buffer(2), 1);
% Streaming refill with content of buffer(4):
PsychPortAudio('FillBuffer', pahandle, buffer(4), 1);
% Wait for end of playback, then stop:
PsychPortAudio('Stop', pahandle, 1);
% Delete all dynamic audio buffers:
PsychPortAudio('DeleteBuffer');
% Close audio device, shutdown driver:
PsychPortAudio('Close');
fprintf('\n\nDone. Bye!\n\n');
return;
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