PDA

View Full Version : [ubuntu] meaning of mencoder options



linuxrockz
March 28th, 2009, 03:21 PM
Hi I may sound stupid but would anyone plz tell me the meaning of the various options used in these commands. I know what they do but I can't seem to follow what the parameters mean.

$ mencoder vcd//:2 -oac lavc -ovc lavc -o filename.avi


mencoder -vf rotate=1 -ovc lavc -oac file1.avi -o file2.avi

Plz explain what these "-oac lavc -ovc lavc -o " parameters mean

Thanks.

andrew.46
March 29th, 2009, 09:29 AM
Hi linuxrockz,


Hi I may sound stupid but would anyone plz tell me the meaning of the various options used in these commands. I know what they do but I can't seem to follow what the parameters mean.


$ mencoder vcd//:2 -oac lavc -ovc lavc -o filename.avi


vcd//:2 Open track 2 of a video CD
-oac lavc Encode the audio with a libavcodec codec (a library of codecs created and maintained by FFmpeg and used by MPlayer)
-ovc lavc Encode the video with a libavcodec codec (a library of codecs created and maintained by FFmpeg and used by MPlayer)
-o filename.avi Create an output file called filename.avi


And the next commandline:




mencoder -vf rotate=1 -ovc lavc -oac file1.avi -o file2.avi


-vf rotate=1 Use a video filter called 'rotate' and spin the image by 90 degrees clockwise
-ovc lavc Encode the video with a libavcodec codec (a library of codecs created and maintained by FFmpeg and used by MPlayer)
-oac There is something missing here, this is a direction to encode the audio but with exactly what is missing :-).
file1.avi This is the input file.
-o file2.avi This specifies the output file


Normally if you specify '-ovc lavc' you would also specify which video codec you would like to use from this group of codecs. For example to encode to MPEG-2 video you would specify:


mencoder input.avi -ovc lavc -lavcopts vcodec=mpeg2video -oac copy output.avi

and the same idea operates with '-oac lavc' where you would specify which audio codec you would like to use. To use wma audio for example you would do the following:


mencoder input.avi -ovc copy -oac lavc -lavcopts acodec=wmav2 output.avi

I hope this has made it all a little clearer? You can see a description of the lavc codecs here:

http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-enc-libavcodec.html

Andrew

linuxrockz
March 29th, 2009, 12:13 PM
Thanks a lot Andrew you have made it very clear.
I am just getting a hand on the ultimate power of the terminal and people like you are a blessing. :-)
Thanks a lot again

Cheers
-Linuxrockz