OGMtools 1.5
==============

--[ IMPORTANT ] ---------------------------------------------------
Up to version 1.2 ogmmerge produced broken headers. Version 1.2 is
now able to read both the old headers and the proper new ones and
will only write proper headers. In order to fix the broken headers
in old files you can simply run something like:
ogmmerge -o good.ogm old_and_broken.ogm
--[ IMPORTANT ] ---------------------------------------------------

These tools allow information about (ogminfo) or extraction
from (ogmdemux) or creation of (ogmmerge) or the splitting of
(ogmsplit) OGG media streams. OGM is used for "OGG media streams".

Base code taken from Ogg/Vorbis CVS repository at
http://www.xiph.org/

Installation is simple. Run './configure' followed by 'make' and
'make install'. If, for some reason, there is no 'configure' script then
run './autogen.sh' which will recreate it.

The full documentation for each command is now maintained in its
man page only. Type 'ogmmerge -h' to get you started.

This code comes under the GPL (see www.gnu.org or the file COPYING).
Modify as needed.

The newest version can always be found at
http://www.bunkus.org/videotools/ogmtools/index.html

Moritz Bunkus <moritz@bunkus.org>

------------------
Example
=======

Here's a *very* brief example of how you could use the ogmtools
with mencoder in order to rip a DVD:

a) Extract the audio to PCM audio and let mencoder calculate the
video frame numbers:

mencoder -dvd 1 -ovc frameno -oac pcm -o frameno.avi

b) Extract the audio again, this time to a plain WAV file:

mplayer -dvd 1 -vc dummy -vo null -hardframedrop -ao pcm -aofile audio.wav

At the moment selecting a non-existant video codec with -vc results
in the fastest audio dump.

c) Normalize the sound (optional)

normalize audio.wav

d) Encode the audio to Vorbis:

oggenc -q3 -oaudio-q3.ogg audio.wav

e) Somehow calculate the bitrate for your video. Use something like...

video_size = (target_size - audio-size) / 1.0115
video_bitrate = video_size / length / 1000 * 8

target_size, audio_size in bytes
length in seconds
1.0115 is the overhead caused by putting the streams into an OGM file.
video_bitrate will be in kbit/s

f) Use the two-pass encoding for the video:

mencoder -dvd 1 -oac copy -ovc lavc \
  -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vqmin=2:vpass=1 \
  -vop scale=....,crop=..... \
  -o /dev/null

mencoder -dvd 1 -oac copy -ovc lavc \
  -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vqmin=2:vpass=2 \
  -vop scale=....,crop=..... \
  -o movie.avi

g) Merge:

ogmmerge -o movie.ogm -A movie.avi audio-q3.ogg

The option -A should be given to avoid copying the raw PCM audio stream.