BCR sometimes incorrectly uses .mp3 file extension

[chenxiaolong]

From #284 (comment):

04-11 18:34:20.462  5628  8743 D OutputDirUtils: Creating 20230411_183403.682-0600_conference_<conference phone numbers>_<conference contact names>.mp3 with MIME type audio/mpeg in content://com.android.externalstorage.documents/tree/primary%3AAudioRecordings%2FBasicCallRecorder/document/primary%3AAudioRecordings%2FBasicCallRecorder

It occurs to me now that I ran into the same problem the other night when I briefly messed with filename formats. To reproduce, simply create a bcr.properties that contains only "filename.1.suffix = Test". Gives me a .mp3 every time.

[chenxiaolong]

Ugh, this is an Android bug/inconsistency:

• MimeTypeMap.getSingleton().getExtensionFromMimeType("audio/mp4") returns m4a
• MimeTypeMap.getSingleton().getMimeTypeFromExtension("m4a") returns audio/mpeg
• MimeTypeMap.getSingleton().getExtensionFromMimeType("audio/mpeg") returns mp3

This becomes a problem any time the output file needs to be renamed (eg. custom filename template or contact name changed during the call, etc.).

The flow that causes the issue:

1. When creating a new file, Android's storage access framework is responsible for adding the file extension. BCR asks it to create <filename> with the audio/mp4 MIME type and it creates <filename>.m4a.
2. Something requires BCR to rename the output file.
3. Android's SAF is terribly inconsistent, so when renaming files, the app is responsible for specifying the file extension, not the framework (EDIT: but only for file:// paths...). BCR queries for the current file type, which Android incorrectly reports as audio/mpeg and then uses that to determine and append the (incorrect) file extension mp3.

This should be pretty easy to fix. When renaming a file, instead of asking Android for the file type, we'll just specify it since we know what it should be.