Audio frames are dropped during on-ongoing record session "retire_capture_urb"

[shaycohen]

When recording an on-going Audio session, using on-board audio device, kernel log shows: "retire_capture_urb: NN callbacks suppressed" During this time-frame, the produced audio file is missing frames.

Reproduced on TinkerOS versions 2.0.7 and 2.0.8 Kernel versions: 4.4.103+ and 4.4.132+

[jamess-huang]

Can you give us a detail configuration and the duplicate step (including the recording command/APP)

[shaycohen]

Hi @jamess-huang , Thanks for the prompt reply. I've attached alsa.conf (as alsa.conf.log in order to comply to GitHub's allowed extensions policy) alsa.conf.log

The recording code snippet is the following (Python3 code):

` import time, redis class Record(): def init(self): self.r = redis.StrictRedis(unix_socket_path="/var/run/redis/redis.sock")

def record_callback(self, in_data, frame_count, time_info, status):
    self.r.xadd("DATA", { b'timestamp': time_info['input_buffer_adc_time'], 'pcm': in_data }, maxlen=2000)
    return in_data, self.paContinue

def record(self):
    import pyaudio
    self.paContinue = pyaudio.paContinue
    audio = pyaudio.PyAudio()
    audioFormat = 8
    channels = 1
    rate = 44100
    index = 1
    chunk = 4096
    self.r.set('START_TS', int(time.time()))
    device=audio.get_device_info_by_host_api_device_index(0,index)
    self.r.set('RECORDER_NAME',device.get('name'))
    stream = audio.open( format=audioFormat, channels=channels, rate=rate, input=1,
    input_device_index=index, frames_per_buffer=chunk, stream_callback=self.record_callback)
    self.r.set("AUDIO_LATENCY", stream.get_input_latency())
    stream.start_stream()
    while True:
        time.sleep(10)
    stream.stop_stream()
    stream.close()
    audio.terminate()
    return

rec = Record() rec.record() `

[jamess-huang]

Sorry to ask this: Did you try to use the same python code on Raspberry Pi or another SBC board ? Just make sure that there is no issue in this python code.

[shaycohen]

I've setup a test environment on an RPi 3B+, using an external / USB audio device (as the RPi onboard does not have a capture interface). Kernel version: 4.19.25-v7+ This device does not seem to have any callback drops nor missing audio chunks on the recorded data.

[rotemtim]

Hi I've just encountered the same problem with tinkerOS 2.0.8, there are a lot of audio chunks drops. @james-huang did you find any resolution to this problem?

[shaycohen]

Hi @jamess-huang Will you please post a short update / ETA about this ? Thank you very much for your support, Shay

[topdjgod]

@shaycohen Could you help to try below sample code to check if it can reproduce? We use below sample code can't reproduce your issue.

import pyaudio import wave

CHUNK = 4096 FORMAT = 8 CHANNELS = 1 RATE = 44100 RECORD_SECONDS = 60 WAVE_OUTPUT_FILENAME = "output.wav" p = pyaudio.PyAudio() stream = p.open(format=FORMAT,channels=CHANNELS,rate=RATE,input=True,frames_per_buffer=CHUNK) print("recording") frames = [] for i in range(0,int(RATE/CHUNKRECORD_SECONDS)): data = stream.read(CHUNK) frames.append(data) print("*done recording") stream.stop_stream() stream.close() p.terminate() wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb') wf.setnchannels(CHANNELS) wf.setsampwidth(p.get_sample_size(FORMAT)) wf.setframerate(RATE) wf.writeframes(b"".join(frames)) wf.close()

@anyone Do you have a simple way to reproduce the problem?

[shaycohen]

@topdjgod Thank you for your support. The proposed code does not use a callback method for capturing audio, thus no callbacks would ever be missed. This method of reading (sequential stream.read) is not good enough when you need to know the exact time stamp of the captured data (normally provided by the audio driver to the callback function as an argument).

Will you please try to reproduce with the code sample I have posted above ?

[topdjgod]

@shaycohen recording_redis.zip Use your sample code as attached file with redis 5.0.4 to test, but still not reproduce it. Could you help to try the attached sample code again?

ps. redis 5.0.4 default the position of redis.sock is in /tmp