Random hangs using USB audio (ALSA)

[clickworkorange]

My python-omxplayer-wrapper implementation randomly hangs, and audio somtimes lags severely behind video. This tends to happen more frequently when the Pi (A+) has been left alone for a little while (a couple of minutes), with OMXPlayer in the paused state. Rapid repeated triggering of the GPIO typically does not provoke the issue. I'm using a USB soundcard (detected as USB HID v1.10 Device [USB AUDIO ]) via ALSA and the snd-usb-audio driver. The issue seems to go away if I unplug the soundcard and instantiate OMXPlayer without the -o alsa argument. The Python code looks like this:

import os
import RPi.GPIO as GPIO
from omxplayer import OMXPlayer

os.system("echo 1 | sudo tee /sys/class/backlight/rpi_backlight/bl_power")

player = OMXPlayer("movie.mp4", args=['--no-osd', '--loop', '--aspect-mode', 'stretch', '-o', 'alsa', '--vol', '-600'], pause=True)

def play_pause(pin):
    if(GPIO.input(pin) == 0):
        os.system("echo 0 | sudo tee /sys/class/backlight/rpi_backlight/bl_power")
        player.play()
    else:
        player.set_position(0)
        player.pause()
        os.system("echo 1 | sudo tee /sys/class/backlight/rpi_backlight/bl_power")

GPIO.setmode(GPIO.BOARD)
GPIO.setup(37, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.add_event_detect(37, GPIO.BOTH, bouncetime=500)
GPIO.add_event_callback(37, play_pause)

try:
    while True:
        pass

except KeyboardInterrupt:
    player.quit()
    GPIO.cleanup()
    os.system("echo 0 | sudo tee /sys/class/backlight/rpi_backlight/bl_power")

"movie.mp4" is a ~1.2mbit 800x480 H.264 video with 128kbit 44.1kHz MP3 audio.

Environment details

Distributor ID: Raspbian Description: Raspbian GNU/Linux 9.3 (stretch) Release: 9.3 Codename: stretch

Software	Version
python-omxplayer-wrapper	0.2.5
python-dbus	1.2.4-1
python-evento	1.0.1
python-decorator	4.2.1
python-RPi.GPIO	0.6.3
python	2.7.13
omxplayer	5a25a57

[jaco01]

I have hangs as well if I use '-o' or '--adev' arguments Regardless of value of arguments (hdmi, both, local, alsa). Additionally, omxplayer won't exit player.sync if using audio output arguments

[willprice]

audio somtimes lags severely behind video

That sounds like an issue with omxplayer, not this library. Can you replicate the issue with omxplayer on the command line or does it only appear when using this library?

[rbckman]

ok, I can confirm that this happens, raspberry pi will hang (zombify the process), nothing else will work but to restart the pi to shut it down, but as Will is pointing out this is probably a fault in omxplayer in it self.. I'm bypassing this problem by playing the audio file separately with aplay, works quite well.