playrec

R2026b

Play and record simultaneously

Since R2025a

Syntax

playrec(as,audioOut)

playrec(as,audioOut,numSamples)

playrec(as)

recordedAudio = playrec(___)

Description

playrec(as,audioOut) plays and records audio simultaneously. Calling playrec starts a new recording and deletes any recorded data that was not previously read.

The default recording length is size(audioOut,1). If you have pre-buffered audio data in the playback queue, the recording length is size(audioOut,1) plus the length of audio data in the playback queue.

playrec(as,audioOut,numSamples) specifies the number of samples to record.

playrec(as) plays queued audio and records simultaneously. The default recording length is the length of data in the playback queue. The function errors if no audio data is in the playback queue. Add audio data to the playback queue using write while playback is paused on as.

recordedAudio = playrec(___) returns the recorded audio data. With this syntax, the function blocks MATLAB^® execution until recording completes.

Examples

Play and Record Audio Simultaneously with audiostreamer

You can play and record audio simultaneously on a full-duplex device using audiostreamer. In this example, you use a full-duplex device to measure an impulse response. Create an audiostreamer object in "full-duplex" mode with a sample rate of 48,000 Hz and one output channel.

as = audiostreamer("full-duplex",48e3, ...
    Driver="ASIO", ...
    Player="Focusrite USB ASIO", ...
    PlayerChannels=1, ...
    Recorder="Focusrite USB ASIO");

Create a sweeptone excitation signal. The excitation signal has a two-second exponential swept sine followed by one second of silence. Call playrec to play the excitation signal while recording simultaneously. Calling playrec with the output argument blocks MATLAB until the recording is finished.

x = sweeptone(2,1,as.SampleRate);
y = playrec(as,x,size(x,1));

Use impzest to compute the impulse response from the excitation and recorded response. Plot the impulse response.

ir = impzest(x,y);
t = (1:size(ir,1))/as.SampleRate;
plot(t,ir)
xlabel("Time (s)")

Input Arguments

as — audiostreamer object

audiostreamer

The audiostreamer object used to play and record the audio.

audioOut — Audio data

column vector | matrix

Audio data to play on the device, specified as a column vector or matrix where the columns correspond to independent audio channels.

Data Types: single | double

numSamples — Number of samples to record

positive integer

Number of audio samples to record, specified as a positive integer.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output Arguments

recordedAudio — Recorded audio data

matrix

Recorded audio data, returned as a matrix where columns correspond to individual audio channels. The number of recorded samples depends on the input parameters and state of the playback queue:

Call to playrec function	State of playback queue of as	Number of samples in recordedAudio
playrec(as,audioIn)	Playback buffer is empty	size(audioOut,1)
playrec(as,audioIn)	Playback buffer has audio data	size(audioOut,1) plus the length of audio data in the playback queue
playrec(as)	Playback buffer has audio data	Length of audio data in the playback queue
playrec(as,audioIn,numSamples)	Playback buffer is empty or has audio data	numSamples

Version History

Introduced in R2025a