.. default-role:: literal


Multimedia documentation
========================

Documents how to do some multimedia tasks

.. contents:: Contents
   :local:

Convert wma to ogg
------------------

You need to dump the ``wma`` file into an uncompressed format (``wav``)::

	$ mplayer -ao pcm:file=/tmp/out.wav $wma_file

Then encode it into ``ogg``::	

	$ oggenc -o ${wma_file%.wma}.ogg /tmp/out.wav

Convert ogg to mp3
------------------

Same as previous section for the dumping part, but use::

         $ lame /tmp/out.wav ${ogg_file%.ogg}.mp3

for the encoding part.

Ripping a DVD
-------------

Download Handbrake_ (command line tool should be enough), and dvdbackup_

Rip the dvd into a temporary directory (here the current directory)::

    dvdbackup -i /dev/dvd -o . -M 

Then list the titles::

    handbrake -i ~/tmp/where_was_ripped -t 0

Do the rip::

    handbrake -i ~/tmp/where_was_ripped -t 1 -o $outfile.mkv  \
        --size 700 --two-pass --audio 1

.. _Handbrake: http://handbrake.fr/
.. _dvdbackup: http://dvdbackup.sourceforge.net/usage.html

Ripping an audio CD
-------------------

There is a script called `abcde`_ that will do this very well. Download and
install it and insert the CD you want to rip. The configuration is made using a
configuration file: `$HOME/.abcde.conf`. Mine just contains::

    OUTPUTTYPE="flac"

Since I wanted to use FLAC_ instead of the default, `Ogg Vorbis`_. The manpage
documents all the configuration file options.

Once you are done configuring `abcde`, just cd to the directory where you want
to rip and run::

    $ abcde

The script will automatically download the disc's metadata (artist, album and
song names, genre...), ask you to confirm them and then rip and encode the
music.

.. _abcde: http://code.google.com/p/abcde/
.. _FLAC: http://flac.sourceforge.net/
.. _Ogg Vorbis: http://www.vorbis.com/

Merging two avi files
---------------------

To merge two avi file *that have the same format* (because e.g they are
splitted into two CDs)::

    mencoder -oac copy -ovc copy file1.avi file2.avi -o output.avi

If `mencoder` tells you the two files do not have the same format, then the
simplest method I have seen is to use `avimerge`, from transcode_::

    avimerge -o output.avi -i file1.avi file2.avi

If you see messages like::

    No audiodata left for track 0->0 (6078000.00=6078000.00) 

And you see that audio is out of sync, you could use the `-c` flag. See the
manpage for more information.

.. _transcode: http://www.transcoding.org/transcode

Merging two mkv files
---------------------

To merge two mkv files, you should use mkvmerge from MKVToolnix_::

     $ mkvmerge --append-mode track -o full.mkv file1.mkv '+file2.mkv'

.. _MKVToolnix: http://www.bunkus.org/videotools/mkvtoolnix/

Playing with subtitles
----------------------

If you want to edit the subtitles or re-time them, the one utility I found
useful is Subtitles_, and its associated command line utility `subs` . As an
example, to shift the times in a `.srt` file 60 seconds later, one can just do::

    $ subs -b 60 file.srt

.. _Subtitles: http://karasik.eu.org/software/

Sound settings in mplayer
-------------------------

Use 0 and 9 to respectively increase or decrease the volume while mplayer is
playing. You can use ``-softvol-max`` to adjust the maximum volume. The
argument that is taken is the maximum amplification level (in percent). For
example::

    $ mplayer -softvol-max 2000 somefile.avi

will allow an amplification of 20 times, at the cost of some lost quality and
granularity.

Extract the audio content of a video file
-----------------------------------------

To get only the audio track of a video file, use mplayer's `-dumpaudio`::

    $ mplayer -dumpaudio $videofile -dumpfile $audiofile

Since this is not always very stable, here is an alternative method using
ffmpeg_::

    $ ffmpeg -i $videofile $audiofile

Where `$audiofile` should have the extension you want, e.g mp3.

.. _ffmpeg: http://ffmpeg.org

Extract images from a video file
--------------------------------

To extract images from a video file, use mplayer's `-vo` option::

    $ mplayer -ss $interval -vo $format -frames $nframes -nosound $file

Where:

* `$interval` is the number of seconds to wait between two frames. Can be a
  decimal number, like 0.01.
* `$format` is the picture format to use. Can be for example `jpeg`, `png`,
  `gif`... 
* `$nframes` is the number of frames to take
* `$file` is the path to your file.

Example::

    $mplayer -ss 0.01 -vo jpeg -frames 5 -nosound mvi_1234.avi

will dump the first five frames of the movie `mvi_1234.avi` encoding them in the
`JPEG`_ format, waiting 0.01 seconds between each frame.

.. _JPEG: http://en.wikipedia.org/wiki/JPEG

Renaming an audio file based on ID3 tags
----------------------------------------

You can use the id3_ tool to edit / read and rename file according to their ID3
tags. One command I often use to rename all files to a `$track-$title.mp3`
format is::

    $ id3 -f '%#n-%t.mp3' *.mp3

.. _id3: http://home.wanadoo.nl/squell/id3.html

References
##########

* The `extracting image from a movie`_ post on mplayer's mailing list.

.. Disappeared...
.. * The `Subtitle manipulation tools`_ article on `Linux.com`.
.. .. _Subtitle manipulation tools: http://www.linux.com/archive/feature/125978

.. _extracting image from a movie: http://lists.mplayerhq.hu/pipermail/mplayer-users/2004-August/047452.html