by WiteWulf » 22 Jul 2014, 10:11
After a few days of smooth running, mostly testing HD audio on local storage, I'm now experiencing serious stuttering issues with many HD files. I'm running an IQaudIO PiDAC and connected to an SMB share on a Mac.
It would appear that there are regular 'head' and 'tail' processes running against the playing files (and sometimes 'md5sum') that, along with 'cifsd', eat up all the CPU, causing mpd to stutter badly. I'm guessing these processes are trying to extract the album artwork and maybe ascertain the file type (16/24 bit, sample rate, etc.).
I think the key here is that this only happens on files accessed over SMB/CIFS. Similar files on local USB storage don't present the same issues as the cifsd high CPU isn't brought into the equation (and local access is faster, anyway, so the CPU is highly utilised for a shorter space of time).
*edit* playing back HD audio from the SMB share seems to operate without issue if I do not have a UI open in a web browser, but as soon as I open a browser session to the UI it kicks off the afore mentioned head, tail and md5sum processes that cane the CPU and introduce stuttering audio again. As soon as the album artwork is displayed playback returns to normal.
A suggestion: could you get the UI to use any folder.jpg present in the enclosing folder in preference to attempting to extract artwork from the currently playing track? This would eradicate this issue for users with these files in place. FWIW, I use iTunes for managing my library and this script extracts album artwork and saves it as folder.jpg on the folder:
- Gary
