Allow apps to read reserved file types on SD card
The SD Card support in WP8 is practically useless because built-in apps are the only ones allowed to access what are known as 'reserved file and URI associations'. (http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj207065(v=vs.105).aspx)
This means it is impossible to create an app that plays video or audio files stored on the SD card. Many WP8 devices ship with only 8GB, which makes the use of the SD card essential, especially to store large files, such as video. We are presently working on a WP8 version of an app to play sign language videos, but are stymied by this restriction. We cannot read (or even see) any .mp4 files on the SD card.
This limitation basically stops our project for WP8. Of course, we have iOS and Android versions that work on phones.
Our own project aside, it seems somewhat draconian to disallow any third-party apps from competing with the built-in apps. Just looking at the list of reserved file types - seems like all file types known to man are reserved. And then I remind myself that this is just on the SD card. But then what is the point of the SD card, if the developer is restricted to the phone's internal memory...
@manikanta : Can you please elaborate on how to access reserved filetypes from Windows phone SDcard?
Actually file types reservation are only for launching. You can read any file type on SD card provided they are system reserved folders. Unfortunately music+videos folder in restricted. From those folders which OS creates in your SD card, everything else can be read.