stream.time raises when the time is 0.0 (PortAudioError: Error getting stream time.. on RaspberyPI)

[RmStorm]

When I run:

 self.stream = sd.InputStream(device=self.device, channels=1, samplerate=self.fs, blocksize=self.block_size, callback=cb)
 self.stream.start()
 self.stream.time

on my laptop it works.. but when I run it on a raspbery pi I get:

│ /home/monil/repos/silo/tools/scripts/.venv/lib/python3.12/site-packages/sounddevice.py:1078 in time │
│ │
│ 1075 │ │ """ ╭───────────────────────── locals ──────────────────────────╮ │
│ 1076 │ │ time = _lib.Pa_GetStreamTime(self._ptr) │ self = <sounddevice.InputStream object at 0x7fff5eb3d040> │ │
│ 1077 │ │ if not time: │ time = 0.0 │ │
│ ❱ 1078 │ │ │ raise PortAudioError('Error getting stream time') ╰───────────────────────────────────────────────────────────╯ │
│ 1079 │ │ return time 

This probably happens because the raspberry is slow and the time is literally 0.0 which is falsy breaking this check.

I think that is the case because adding a tiny sleep(0.1) before reading the property fixes the issue..

[mgeier]

Thanks for reporting this!

the time is literally 0.0 which is falsy breaking this check.

This is intentional, because the docs state: "The stream's current time in seconds, or 0 if an error occurred."

adding a tiny sleep(0.1) before reading the property fixes the issue.

That's interesting, but it sounds like a bug in PortAudio to me.

When Pa_StartStream() returns (which we are waiting for in stream.start()), Pa_GetStreamTime() should return a non-null value.

Would you like to create an issue at https://github.com/PortAudio/portaudio/issues?

[RmStorm]

I guess it would be nice to verify a little more but I don't really have time to do that. I'm just living with the sleep now haha. A cursory glance at portaudio makes it seem plausible though. They don't verify the result !=0 before returning it I think:

https://github.com/PortAudio/portaudio/blob/19640aad8f2f79fb9cd14e20eb1410237b98377f/src/common/pa_front.c#L1610-L1617

I'll make an issue over there and see what comes of it.

[chivermetimbers]

Hi there, I've been running into a similar issue and figured I would add what I've been experiencing.

Describe the bug
Expect that Stream.time() returns the time since the streams beginning. But have had mixed results both getting a time at all and getting the correct time.

The following code raises the sounddevice.PortAudioError: Error getting stream time error:

import numpy as np
import queue

# set the amount of samples 
fs = 8000
duration = 10

sd.default.samplerate = fs
sd.default.channels = 1
sd.default.device = 0, 1

q = queue.Queue()
p = queue.Queue()

def callback(indata, frames, time, status):
 if status:
 print(status, file=sys.stderr)
 # Original audio sample
 q.put(indata.copy())
 # Magnitude spectrum of the frame
 mag_spec = np.fft.fft(indata.copy())
 p.put(mag_spec)

with open('recording.npy','wb') as f, open('magnitude_spectrum.npy','wb') as g:
 # only process 1 frame at a time in the callback function
 with sd.InputStream(callback=callback,blocksize=1) as i:
 i.start()
 print(i.time)
 
 while True:
 np.save(f,q.get())
 np.save(g,p.get())
 if i.time > duration:
 i.close()

The issue here is the line if i.time > duration, which raises the error. On the other hand, if I evaluate the if statement outside of the while loop:

with open('recording.npy','wb') as f, open('magnitude_spectrum.npy','wb') as g:
 # only process 1 frame at a time in the callback function
 with sd.InputStream(callback=callback,blocksize=1) as i:
 i.start()
 print(i.time)
 if i.time > duration:
 i.close()

this does give me a value which is much larger than is possible for the stream 1748958.021352708 which in days is about 20. I think this roughly coincides with when I first started toying around with sounddevice, so maybe there's a way to find and close an open stream that has somehow been open this long. That being said, if this is the case then why is it mixing up my input stream with one that has been open for 20 days?

To reproduce
I'm using a conda environment with the following dependencies:

cffi==2.0.0
numpy==2.4.6
pycparser==3.0
sounddevice==0.5.5

on an M1 Macbook Pro with

ProductName: macOS
ProductVersion: 15.7.3
BuildVersion: 24G419

Unfortunately I'm unable to use this sleep solution and I really require the correct time since stream onset since I intend to use this in an experimental setting.

Interestingly, I've found that when running some code very similar to the sounddevice examples:

import sounddevice as sd

fs = 8000
duration = 10

sd.default.samplerate = fs
sd.default.channels = 1
sd.default.device = 0, 1

def callback(indata, outdata, frames, time, status):
 if status:
 print(status)
 outdata[:] = indata

with sd.Stream(callback=callback):
 sd.sleep(int(duration * 1000))

I've found out that when running the vscode debugger that the time value associated with sd.Stream() in this case is the same as what I've computed in the 'working' example described above.

Maybe this gives some context and hopefully moves us closer to a solution. I would fix it myself but I have no idea where to start.

EDIT
Based on the documentation for Pa_GetStreamTime()

Pa_GetStreamTime returns valid time values for the entire life of the stream, from when the stream is opened until it is closed. Starting and stopping the stream does not affect the passage of time returned by Pa_GetStreamTime.

One would expect i.close() to reset the time.