How can I make mediascanner scan phone memory, i.e. the /data directory? I want to test playing MP3s from this directory.

When I try to hack it by replacing the "pathStr" from /mnt/sdcard to /data before MediaScanner::doProcessDirectory(), it fails saying

W/MediaScanner( 1713): Error opening directory '/data/', skipping: Permission denied.

And also crashed (probably in free).

I just want to play MP3s stored in phone memory and avoid reading the SD card for some experiments.

  • Without root one program can't access /data of another program.
    – roxan
    Jul 20 '12 at 8:25
  • Roxan, I understand that but how can I play mp3 from /data folder?
    – dls
    Jul 20 '12 at 8:33
  • I mean, Can I change root permission for this process somewhere?
    – dls
    Jul 20 '12 at 8:34
  • Have you tried browsing using a root file explorer such as FX, and playing through that? Having said that, you'll probably need to run the media player as root too.
    – Jeeva
    Jul 20 '12 at 9:21
  • How do you use FX? I see one app called MusicFX in my /packages/apps, will this be able to do that??
    – dls
    Jul 20 '12 at 11:04

EDIT: This is rendered obsolete with Jelly Bean. Android 4.1+ has a unified /data/ and /sdcard section (the sdcard partition is emulated and really resides in /data/media, it's exposed via a special fuse layer to emulate FAT32 behaviour)

My thoughts on this:

  • The media scanner scans everything below /mnt
  • /data/* is protected, only individual apps can access their folder (/data/data/[app's package name])

To get it working the way you like:

  • You need root (obviously)
  • symlink /mnt/music to /data/data/your-music-location
  • you can also do a bind-mount instead of a symlink:
    mount --bind /data/your-music-location /mnt/sdcard/your-music-location
  • Lift access rights accordingly (chmod -R ugo+rw /data/data/your-music-location)

Hope this works (the scanner should scan the whole /mnt as there's also /mnt/emmc and such). If not, you can also bind-mount a /data/data/* folder to /mnt/sdcard/your-music (as done with /mnt/sdcard/.android_secure (see the answer))

  • I realize that /system folder has permissions and does not require root permissions.
    – dls
    Jul 20 '12 at 11:37
  • Don't use system. It's mounted read-only and must only be used for firmware (or root-related) stuff. I'd also suggest not to use data, except for testing and learning. Does it offer so much more space than your sd card that it's worth it?
    – ce4
    Jul 20 '12 at 11:39
  • How can I list music also from /system/media/audio into music player? This will help me to play the mp3 from system memory rather than SD Card. I want to make minimal change to do this. By hacking at some place in mediaScanner I think it is possible but is there a better method where I can list music from SD Card as well as from /system/media/audio ??? Thanks in advance.
    – dls
    Jul 20 '12 at 11:39
  • I am using only for some experimental setup. So I am fine with using /system also for mp3 playback.
    – dls
    Jul 20 '12 at 11:42
  • Be warned, editing /system will survive a wipe (or reset), FYI. maybe do a 'ln -s /your/music/location /mnt/music' and have the rights set appropriate. You need to remount /system read-write before you can write to /music. AGAIN: I suggest you don't do this. (Asking such question here implies you should be more aware of the risks involved. At least IMHO)
    – ce4
    Jul 20 '12 at 11:48

To furnish my thoughts, hacking on just the in-built media-scanner will not just suffice, as that requires rolling your own ROM! The reason being is that media-scanner is signed with a system certificate that is shared with the ROM in question.

And thus, that requires having the signed keys from the original ROM in order to replace the in-built media-scanner.

As to attempting to put MP3s in the /system/media/audio folder - why? Are we talking about album mp3s which can creep up to between 5-8Mb in size? Or are we talking about Ogg Vorbis for ringtones/notifications?

The /system partition is limited in size depending on the manufacturer's handset setup in terms of partition layouts.

If the audio media is stored on the SDCard under the respective directory /sdcard/media/audio/Ringtones and /sdcard/media/audio/notifications, along with a URI (Uniform Resource Identifier) pointing to the appropriate media declared as "external storage media" as in "MediaStore.Audio.Media.EXTERNAL_CONTENT_URI" (see the Developer Documentation on this), it will get picked up by Android itself and will show under the Settings > Sounds, as 'Phone ringtone' or in 'Notification ringtone'.

Depending on the ROM in itself, there may be a Development tools called 'Dev Tools', in there, there is an activity which can trigger the invocation of the in-build Media-Scanner, this is in stock/vanilla AOSP Android.


If you have a standard Linux file system (i.e., not FAT32) on your SD card, you could create Soft Link of /data in /mnt/sdcard.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.