iPod Classic 4G won't play m4a files

[girolamous]

I just installed Rockbox 3.12 on an iPod 4G classic.  When I try to play any of several .m4a files, it plays/pauses/plays/pauses...forever, seemingly making the UI very unresponsive.  Looking across the internet, this was a problem that supposedly got fixed several years ago.  Is it the old hardware that is the problem here, or what?  I had Rockbox on this very iPod a few years ago, and don't recall having had any issues with it, but then I didn't play many AAC-coded files back then before iTunes Match.  Is there a better version of Rockbox for this, or do I have to transcode my files?

Thanks!

[saratoga]

Are they aac he files?  Your iPod isn't fast enough to decode those.

[Julian67]

I had similar trouble with some LC AAC m4a on my old iRiver players, which would sometimes just skip the files and other times would hang on very high bitrate m4a, especially large files, and force me to do a hard reset.  Most of the files in question would play fine on a newer player with more powerful CPU i.e. Sansa Clip+ or Fuze or Rockbox as an Application on an Android device, but some would fail to play even on these relatively powerful devices.

I was able to solve the problem by hinting the files with MP4Box http://gpac.wp.mines-telecom.fr/mp4box/

"MP4Box -hint <your_file>"

basically optimizes the file for streaming (at the cost of slightly increased file size) and this seems to also make it easier to read/decode for very low power devices like an iRiver H140.  Your iPod is even less powerful but it might be worth a try.  MP4Box is available for Windows, OS X, iOS, Android and is in the repositories of Debian and similar.

If you run Linux/BSD/Mac then this script might be helpful in avoiding hinting files which are already hinted (they get bigger each time, so it's best avoided).  I set it to ignore all except suitable m4a/m4b/mp4 files so I can lazily run it on directories with mixes of audio and cover art and text files without error messages.  It writes an optimised temp file to /tmp instead of in situ, and then overwrites the original.  That seems odd but is noticeably quicker than default (two writes to disk in situ) when the file resides on a slow disk (probably with very fragmented file system) such as is commonly found in ancient hard disk personal players.

Code: [Select]

#!/bin/bash
#hint_m4a

for i in "$@"; do

shopt -s extglob nocasematch
if [[ "${i##*\.}" == !(m4a|m4b|mp4) ]] ; then
continue
fi

MP4Box -info "$i" |grep "Streaming Hint Track"
if (( $? == 1 )) ; then MP4Box -hint "$i" -out /tmp/"${i##*/}" && \
mv /tmp/"${i##*/}" "$i"
fi

done

If your files are from iTunes they are already be optimised/hinted so there's not much you can do.  Most of my problem files are LC AAC I've muxed with ffmpeg and need hinting to make them playable in RockBox.  If you run Windows and prefer a graphical app I know that dbpoweramp converter can optimise/hint m4a.

[girolamous]

Hi, and thanks for the useful replies. 
I figured the problem lies in the low processing power of a 9 year old iPod.  What was confusing me was that, as I recalled, it was playing these same files a couple of years ago before I got involved with iTunes Match.  I don't recall what format this particular file was in originally, but now it is m4a.  Whatever it is, it seems that it went away after I rebooted my player following a hard drive failure. 
The hard drive on this unit has had some issues in the past, so this is not new.  What is odd is that one particular file began playing correctly.  Not sure why this is happening, but I will go through some more of my playlists and see what happens.

Thanks,
Jerry