My anime are in MP4 and the most audio code used is AAC, honestly, till today, I have encounter very little issue playing them.
There are a few “Known” issues with MP4 and/or AAC:
– Audio garbling/static when playing MP4+AAC after playing other certain types of media. Easy fix: Play a different file with a different audio codec, and then the MP4 / AAC will be fine.
– MP4 video will begin to race forward when switching audio tracks.
– SRT / SSA / A-S-S subtitles don’t appear to be supported in MP4.
– VobSub subtitles will make the image flicker when subtitle changes.
– Audio will ocassionally be out of sync with video, but this is fixable with the LIP SYNC function in the options menu.
I call these “Known” issues, as they have been reported to WD. I don’t know what they’re doing or if they can reproduce the issue in their labs.