[SOLVED] Clocking / Timing issues with DAC Pro’s internal clock

Since yesterday I’m a proud owner of a brand new HifiBerry DAC+ Pro / RasPi 3B+
After initial setup with the current max2play image, I tried with the stable 7.9.1 release of squeezebox.
Most things worked as expected and I was happy.

But I discovered today that some Radio Streams had sync / buffering issues. I was able to track it down to a streambuffering difference between
the calculated and real buffer position, as shown in the squeezelite sdebug log, marked in my example with XXXX:

[22:41:30.006471] sendSTAT:198 received bytesL: 2473952 streambuf: 1082 outputbuf: 961544 calc elapsed: 100353 real elapsed: 100405 (diff: XXXX) device: 52 delay: 6

The difference was growing fast when playing the Radio streams and when it exceeded a value of around 2500 resulted in stuttering or resyncing.

To track it further down, I started to debug the playback of mp3 files from the local music library. And guess: The playback is much too fast, resulting in a rapidly growing diff value. I tried it with Pink Floyd’s „Time“ from Dark Side of The Moon, which has a length of 7:04. The real playback time measured with my stop watch is 6:30 – 34 seconds difference. And this value is exactly represented in the sdebug log (34428 ms):

[17:34:34.005094] sendSTAT:198 received bytesL: 2454463 streambuf: 2097151 outputbuf: 3300984 calc elapsed: 424241 real elapsed: 389813 (diff: 34428) device: 58 delay: 20

After searching and reading through a lot of topics I finally learned that you can switch off the internal clock usage of the HifiBerry DAC+ Pro, so that it behaves like a DAC+ using the RaspBerry’s clock. You do that in the boot/config.txt with:

dtoverlay=hifiberry-dacplus,slave=on

Before: aplay -l -> Karte 1: sndrpihifiberry [snd_rpi_hifiberry_dacplus], Gerät 0: HiFiBerry DAC+ Pro HiFi pcm512x-hifi-0 []
After : aplay -l -> Karte 1: sndrpihifiberry [snd_rpi_hifiberry_dacplus], Gerät 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0 []

And guess: After that magic switch the timing is correct and the diff stays in a reasonable range (around -55 … -50).

Of course I want to use HifiBerry DAC+ Pro’s full functions. So I’ve already updated everything: max2play Beta, latest nigthly of squeezebox Server, latest squeezelite update, RaspBi Kernel update and update of all OS packages. But nothing helps.

Would be great if someone who’s deeper into that topics could confirm my issue and support me or the developers in fixing it.

Best regards,
Marek

• This topic was modified 5 years, 8 months ago by sti.
• This topic was modified 5 years, 8 months ago by Heiner.