When I try to install "ubuntu restricted extras" in "ubuntu software center", it displays a warning dialog that says the following items must be removed:

libavcodec53

libavutil51

Why? And if I choose to install "ubuntu restricted extras", what will I lose?

PS: I think I noticed libavcodec53 flash past as my daily build of codeblocks package was installing... so that's one possibility. Will I break my software development environment if I install "ubuntu restricted extras"?

Or do these packages need to be removed because they are included in "ubuntu restricted extras"? If so, why doesn't the dialog mention that (and remove the worry and confusion)?

PS: The output generated by apt-get -s install ubuntu-restricted-extras is

NOTE: This is only a simulation!

      apt-get needs root privileges for real execution.

      Keep also in mind that locking is deactivated,

      so don't depend on the relevance to the real current situation!

Reading package lists...

Building dependency tree...

Reading state information...

The following extra packages will be installed:

  cabextract gstreamer0.10-plugins-bad-multiverse libavcodec-extra-53

  libavutil-extra-51 libfaac0 libmjpegtools-1.9 libopenjpeg2 libquicktime2

  ttf-mscorefonts-installer unrar

Suggested packages:

  libfaad0

The following packages will be REMOVED:

  libavcodec53 libavutil51

The following NEW packages will be installed:

  cabextract gstreamer0.10-plugins-bad-multiverse libavcodec-extra-53

  libavutil-extra-51 libfaac0 libmjpegtools-1.9 libopenjpeg2 libquicktime2

  ttf-mscorefonts-installer ubuntu-restricted-extras unrar

0 upgraded, 11 newly installed, 2 to remove and 0 not upgraded.

Remv libavutil51 [4:0.8.3-0ubuntu0.12.04.1] [libswscale2:amd64 libavcodec53:amd64 gstreamer0.10-ffmpeg:amd64 libpostproc52:amd64 libavformat53:amd64 ]

Inst libavutil-extra-51 (4:0.8.3ubuntu0.12.04.1 Ubuntu:12.04/precise-updates [amd64])

Conf libavutil-extra-51 (4:0.8.3ubuntu0.12.04.1 Ubuntu:12.04/precise-updates [amd64])

Inst libopenjpeg2 (1.3+dfsg-4 Ubuntu:12.04/precise [amd64])

Remv libavcodec53 [4:0.8.3-0ubuntu0.12.04.1] [gstreamer0.10-ffmpeg:amd64 libavformat53:amd64 ]

Inst libavcodec-extra-53 (4:0.8.3ubuntu0.12.04.1 Ubuntu:12.04/precise-updates [amd64])

Conf libopenjpeg2 (1.3+dfsg-4 Ubuntu:12.04/precise [amd64])

Conf libavcodec-extra-53 (4:0.8.3ubuntu0.12.04.1 Ubuntu:12.04/precise-updates [amd64])

Inst cabextract (1.4-1 Ubuntu:12.04/precise [amd64])

Inst ttf-mscorefonts-installer (3.4ubuntu3 Ubuntu:12.04/precise [all])

Inst libfaac0 (1.28-0ubuntu2 Ubuntu:12.04/precise [amd64])

Inst libquicktime2 (2:1.2.3-4build2 Ubuntu:12.04/precise [amd64])

Inst libmjpegtools-1.9 (1:1.9.0-0.5ubuntu7 Ubuntu:12.04/precise [amd64])

Inst gstreamer0.10-plugins-bad-multiverse (0.10.21-1 Ubuntu:12.04/precise [amd64])

Inst ubuntu-restricted-extras (57 Ubuntu:12.04/precise [amd64])

Inst unrar (1:4.0.3-1 Ubuntu:12.04/precise [amd64])

Conf cabextract (1.4-1 Ubuntu:12.04/precise [amd64])

Conf ttf-mscorefonts-installer (3.4ubuntu3 Ubuntu:12.04/precise [all])

Conf libfaac0 (1.28-0ubuntu2 Ubuntu:12.04/precise [amd64])

Conf libquicktime2 (2:1.2.3-4build2 Ubuntu:12.04/precise [amd64])

Conf libmjpegtools-1.9 (1:1.9.0-0.5ubuntu7 Ubuntu:12.04/precise [amd64])

Conf gstreamer0.10-plugins-bad-multiverse (0.10.21-1 Ubuntu:12.04/precise [amd64])

Conf ubuntu-restricted-extras (57 Ubuntu:12.04/precise [amd64])

Conf unrar (1:4.0.3-1 Ubuntu:12.04/precise [amd64])