Transcode

Transcoding is the process of taking a video file and changing it to a different format or bitrate.

Transcoding in VLC copies the movie to a new file in a different format, so you end up with both the original and new files. This means you need to have enough space on your hard drive to store this extra file. You should also have a reasonably fast computer, as transcoding can be very slow.

In VLC, transcoding is exactly the same as streaming accross a network, except that the output is sent to a file instead of a network.

Transcoding with the Wizard

VLC includes a transcoding and streaming wizard. To transcode a file, just select the transcode option. You will then be asked what format to convert to: you can give a video codec, and audio codec and an encapsulation format. Only some encapsulation formats can support some codecs - look here to see what supportes what.

For more information, see VideoLAN's Official Documentation

Transcoding with the Command Prompt

The most flexible way to transcode with vlc is using a command prompt to start vlc. Transcoding works the same as streaming. For example, the following command changes an asf file to an MPEG-2 file:

vlc "C:\Movies\Your File.asf" :sout='#transcode{vcodec=mp2v,vb=4096,acodec=mp2a,ab=192,scale=1,channels=2,deinterlace,audio-sync}:std{access=file, mux=ps,url="C:\Movies\Your File Output.ps.mpg"}'

The access=file instructs vlc to store the output in a file (and not stream it), and the url is the location of the new (output) file.

(Note: If you are running VLC on Mac OS X, you should use clivlc instead of VLC to avoid possible Bus error problems.)

Transcoding takes quite a while, so it's advisable to use an option like --stop-time=30 to only encode the first 30 seconds - this means you can check the file has transcoded correctly, and that the output is of a suitable quality.

The transcode statement can contain vcodec and vb to change the video codec and acodec and ab to change the audio codec. If vcodec is missing, the video codec will stay the same (same for acodec).

Common additional options to use are audio-sync (to make sure the audio is in sync correctly) and deinterlace (to increase quality slightly on interlaced video).

Completely non-interactive transcoding

For completely non-interactive transcoding (such as the case necessary when running under Mac OS X), the above example could be rewritten as

vlc -I dummy "C:\Movies\Your File.asf" :sout='#transcode{vcodec=mp2v,vb=4096,acodec=mp2a,ab=192,scale=1,channels=2,deinterlace,audio-sync}:std{access=file, mux=ps,url="C:\Movies\Your File Output.ps.mpg"}' vlc:quit

The two extra options are

-I dummy

Disables the graphical interface

vlc:quit

Quit VLC after transcoding

For more information, see VideoLAN's Official Documentation