topic Re: Sometimes first few seconds of audio doesn't play in i.MX Processors

Sometimes first few seconds of audio doesn't play

harry_cheng — Mon, 23 Dec 2019 19:08:15 GMT

I have a board based on i.MX 6Quad SABRE, running "imx6qsabresd 3.14.28-1.0.0_ga+g91cf351". Recently I'm trying to play mp3 or wav audio files with HDMI monitor, and I found sometimes the beginning of the audio are cut off. I tried gst-launch-1.0 and aplay, both have this behavior. It happens randomly, and the lost part could be anywhere below 3 seconds.

Based on some posts, it looks similar issue happens to PC and windows, too. Mostly it's related to power saving. With alsa, "options snd-hda-intel power_save=0" fixes the issue for some platforms. I was hoping there is a similar configuration for imx but I couldn't find any.

I did find an easy "workaround": If I keep playing anything such as silence with "gst-launch-1.0 audiotestsrc wave=silence ! autoaudiosink", the real audio files work perfectly. But it uses 5% to 10% of CPU, which I don't want to waste.

A configuration would be an elegant solution. Otherwise I might need a patch on alsa-lib or the kernel.

Thanks. Any suggestion is appreciated.

Re: Sometimes first few seconds of audio doesn't play

igorpadykov — Tue, 24 Dec 2019 02:47:29 GMT

Hi Harry

one can try with nxp imx-gst1.0 gstreamer plugins described in Linux Guide included in

Linux 3.14.28 BSP & Multimedia Codecs Documentation

and with more new nxp kernels described on

i.MX Software and Development Tools | NXP

Best regards
igor
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Re: Sometimes first few seconds of audio doesn't play

harry_cheng — Tue, 24 Dec 2019 18:41:23 GMT

Igor,
Thank you for your answer.

I got an error from pulsesink: "error: Failed to connect: Connection refused". So I'm still trying to fix it.

However, I am not really confident it will work. It looks pulsesink still uses alsa as backend, and I suspect the issue is with alsa or even lower level, because I have the same issue when playing raw audio:
gst-launch-1.0 filesrc location=/home/root/somefile.mp3 ! mad ! filesink location=/home/root/decoded.audio
aplay -f s32 -r 44100 -c 2 decoded.audio

Thanks.