Step 7 - Multiplexing

Introduction

By now you should have both an audio stream (.mp2) and a video stream (.mpv) ready. Before we move on, we have to combine these. This is called multiplexing. We use bbMPEG for this, since it can produce SVCD compliant multiplexed streams. It can also split the resulting stream, given a filesize - so we can divide it up on a number of CD's.

How to

In case your movie is NTSC/FILM we have to perform a "3:2 pulldown when playback" before multiplexing it. We do this with the command line tool "pulldown" (assuming it's in your path) like this:

C:\DVD> pulldown movie.mpv movie-new.mpv
                 <source>  <destination>
          

• Program Stream Settings: Select 'SVCD'. Do this first, since some of your other changes will be reset each time a new 'Program stream type' is chosen.
• General Settings: Set 'Max size (MB)' to the max. number of MB's you want per CD. No more than 795 MB fits on an 80 min. CD, and no more than about 735 MB on a 74 min. CD.
• Input and Output files: 'MPEG Program stream file' is the output file, i.e. the multiplexed file we are about to create; 'MPEG Video Stream temp file' is the MPEG video file (.mpv); 'Audio Stream 1 temp file' is the first MPEG audio file (.mp2) and 'Audio Stream 2 file name' is the second MPEG audio file, if you have one.

When these things are configured press 'OK' to close the window, and hit 'Start' in the other window. The multiplexing is I/O bound, not CPU bound, so the speed will depend on the speed of your harddisk.

Should any sync. problems appear in the log while multiplexing, your total bitrate may be too high to comply with the SVCD standard. What you can try to do, is change 'Forced mux rate' from 6972 to 0 in the Program Stream Settings section. This will cause bbMPEG to ignore the upper bitrate limit. However, this is not recommended. Even if you don't get errors doing this, the movie may contain sync. errors when played back on a standalone DVD player.

When bbMPEG is done multiplexing, you'll have a .mpg file containing both the audio and video streams. You can now open this with a DVD player (e.g. PowerDVD) or even Windows Media Player, if you have an MPEG-2 codec installed.