[MEncoder-users] converting and subtitle questions !

[Jorge Peixoto de Morais Neto]

My previous email was sent incomplete due to a bug in Gmail. Here is
the full text:

> mencoder mov.rmvb -ovc lavc -oac mp3lame -o mov.avi

This command re-encodes the movie. Video codec is from lavc. Since you
did not specify which video codec you want from the ones supported
by lavc, mencoder uses the default MPEG-4 part 2.
Audio codec is mp3 from mp3lame

>  ffmpeg -y -i mov.avi -vcodec xvid -s 400x240 -r 29.97 -b 600 -acodec aac -ac 2 -ar 48000 -ab 128 -vol 200 -f mp4 mov.mp4

This re-encodes the movie again! This diminishes quality!
Also, you are encoding with fixed bitrate in only one pass. This
results in very bad quality.

I recommend the following:

1) Encode with mencoder, two pass. It would be something like this

First pass:
mencoder -o mov.avi -ovc lavc -vf scale=400:240
-lavcopts:vmax_b_frames=2:vb_strategy=2:brd_scale=2:mbd=2:trell:v4mv:last_pred=3:predia=3:dia=3:cbp:preme=2:vqcomp=0.6:vbitrate=600:vpass=1:turbo
-oac faac -faacopts br=128 mov.rmvb

Second pass:

mencoder -o mov.avi -ovc lavc -vf scale=400:240
-lavcopts:vmax_b_frames=2:vb_strategy=2:brd_scale=2:mbd=2:trell:v4mv:last_pred=3:predia=3:dia=3:cbp:preme=2:vqcomp=0.6:vbitrate=600:vpass=2
-oac faac -faacopts br=128 mov.rmvb

Note: why did you explicitly specify the framerate (29.97), audio
sampling frequency (48000) and number of audio channels (2) ? Usually
people just accept the default.

For more information about mencoder, read
http://www.mplayerhq.hu/DOCS/HTML/en/mencoder.html and
http://www.mplayerhq.hu/DOCS/HTML/en/encoding-guide.html

2) Now you should *remux* your avi file to mp4. ***remux is different
from re-encoding***. Another person suggested you to use the muxer
MP4Box. I have never used this program, but it seems may people use
it. It is probably a good choice.