mplayer lacks png alpha support

[salsaman]

The current version of mplayer which is shipped with Ubuntu Trusty has broken support for png / alpha image output. This in turn breaks other packages, in particular the LiVES application (http://lives.sourceforge.net).

Tested with mplayer version 2:1.1+dfsg1-0ubuntu3.

To reproduce:
mplayer -vo png:alpha <any_video_file>.

Expected result: produces numbered sequence of png images (works with the :alpha omitted).

Actual result: error and no ouput produced.

I believe this can be fixed very simply by adjusting the compilation options for mplayer.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Borim (borim)]

This bug seems to exists for many years e.g. it was reported in the ubuntu forums at 2010:
http://ubuntuforums.org/showthread.php?t=1513793

It would be great if this bug will be fixed, as it affect other programs, too.