Using mencoder to encode movies at sdm networks weblog

This article wants to cover some basic and advanced encoding using mencoder as the encoding engine. Basically all media MPlayer can read is suitable for this howto.

Source

MPlayer knows of those sources (use these in substitution for SOURCE in below examples):

file: uses a file as input
URL: uses an URL as input (useful for streams)
playlist: uses the given playlist as input
-: uses stdin as input
[dvd|dvdnav]://[title|[starttitle]-endtitle]: uses a DVD as input
vcd://track[/device]: uses a VCD as input
tv://[channel][/input_id]: uses some TV channel
radio://[channel|frequency][/capture]: uses some radio channel
pvr://: uses video-in of your TV card
dvb://[card_number@]channel: uses DVB channel
mf://[filemask|@listfile]: uses a list of jpg/png files
[cdda|cddb]://track[-endtrack][:speed][/device]: uses audio CD

If you are unsure which source you want to use consult the man page:

man mplayer

Copying

If you just want to copy some SOURCE without changing its coding then this is what you need:

mencoder SOURCE -oac copy -ovc copy /tmp/MOVIE.avi

Encoding

Here is an example of encoding some SOURCE to DivX with Mp3 sound.

mencoder SOURCE -oac lavc -ovc lavc -lavcopts ↵
vcodec=divx:acodec=mp3:vbitrate=1800:abitrate=128 ↵
/tmp/MOVIE.avi

Languages

To select a specific language you need these parameters:

mencoder SOURCE OPTIONS -alang en -slang de /tmp/MOVIE.avi

Crop and Scale

Cropping cuts off parts of the visible movie screen. Scaling uses the input resolution and scales it to the given resolution. Scaling uses a lot of CPU and negatively effects not only encoding time but also quality.

mencoder SOURCE OPTIONS -vf crop=720:544:0:16,scale=720:576

MPlayer has a neat method to extract those values from the movie. Just run

mplayer SOURCE -vf cropdetect

and MPlayer will generate a lot of output. Let the movie play until these parameters don’t change anymore.

Errors on Encoding

From time to time you encounter a DVD you cannot encode. mencoder stops encoding and your DVD-drive makes a suspicious noice. This happens almost always at the beginning of the encoding process. Then you have two options to choose from:

leave alone that DVD and don’t copy/rip it
crop some seconds/minutes from the beginning

If your choise was number two - congratulations and welcome in my world. The first few seconds, eventually minutes, of every movie are the opening credits. If you’re not that much interested in this information then continue as follows.

mencoder -ss 40 SOURCE -ovc copy -oac copy -o /tmp/MOVIE.avi

The switch -ss tells mencoder to seek forward 40 seconds and start encoding at this position.

sdm networks weblog