Add support for physical DVDs in drives (perhaps through libdvdread)

[Leo Izen]

Summary of the bug:
FFmpeg cannot read physical discs, especially if they're encrypted.

How to reproduce (with an encrypted DVD):

ffmpeg -i /dev/sr0

analyzes my DVD as an MP3 with:

[mp3 @ 0x12c6e60] Format mp3 detected only with low score of 1, misdetection possible!

Using

ffmpeg -f mpeg -i /dev/sr0

does not obtain the audio stream and provides an incorrect video stream for playback (because of encryption).

Proposed fix:
Add support for something along the lines of

ffmpeg -f libdvdread -i /dev/sr0

libdvdread can automatically decrypt dvds if you have libdvdcss installed, and it won't fail silently if you don't.

[Carl Eugen Hoyos]

Duplicate of #3280

[Leo Izen]

This is not a duplicate of #3280 because that requests support for dvdnav packets where I am specifically requesting support for encrypted physical DVDs through libdvdread. (AFAIK you can't read from an encrypted ISO, you NEED the disc.)

[Carl Eugen Hoyos]

Then I suggest to test this ticket again once #3280 is implemented.