I want to add/cat file with this command: `-add /mnt/sdcard/newtarget3.mp4 /mnt/sdcard/media.mp4` using mp4box android. 
Then i get the following output: `[31mCannot open destination file /mnt/sdcard/media.mp4: I/O Error`
`[0m`


Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [x ] I looked for a similar issue and couldn't find any.
- [x ] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [ x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

MP4Box Android: I/O Error
This is a GitHub Issue
repo:gpac
owner:gpac
Title : MP4Box Android: I/O Error
Issue date:

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I want to add/cat file with this command: `-add /mnt/sdcard/newtarget3.mp4 /mnt/sdcard/media.mp4` using mp4box android. 
Then i get the following output: `[31mCannot open destination file /mnt/sdcard/media.mp4: I/O Error`
`[0m`


Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [x ] I looked for a similar issue and couldn't find any.
- [x ] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [ x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

--- end body ---
