<div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">> Well, as far as I know, the general rule is: if MPlayer can play it,<br>> Mencoder can read it and encode to a other format.
<br>><br>> I never encode to MPEG2, but this should work for encoding it to MPEG4. I'm<br>> sure encoding to MPEG2 won't be very different:<br>><br>> mencoder -mc 0 -oac mp3lame -lameopts mode=0:abr:br=160 -ovc lavc -lavcopts
<br>> vcodec=mpeg4:vbitrate=2000 -o "$OUTPUTFILE" -quiet "$INPUTFILE"<br>><br><br>I substitued 'mpeg4' with 'mjpeg' and successfully transcoded the<br>sample BBC 1080i clip I dowloaded from here<br>
<br><a href="http://www.giusberto.ch/hdtv/">http://www.giusberto.ch/hdtv/</a><br><br>(I presume it's the same one mentioned by the OP, since it also<br>features David Attenborough and a storm)<br><br>into something that plays full speed with picture and sound on my AMD
<br>64 3000. However I have much still to understand. For one thing the<br>transcoded clip is smaller than the original (40MB vs 50MB), so either<br>I've lost some of the quality or I didn't get to the end of the clip,</blockquote>
<div><br>You will ALLWAYS lose some quality if you re-encode to a lossy format like MPEG2, MPEG4 or MJPEG<br><br>The reason the file is smaller is probably because you (or I) mucked about with the bitrate, which in my example is set to 2000kbit/s. Change this number to get larger or smaller files that are of better or worse quality.
<br><br>It's allso possible that you threw away some audio quality and/or audio channels (like from 5.1 to stereo) you could try copying the original audiotrack like this:<br> <br>mencoder -mc 0 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=2000 -o "$OUTPUTFILE" -quiet "$INPUTFILE"
<br><br>This will allso improve the time required for encoding (because you don't encode audio at all, you just copy it)<br></div></div><br>This re-encoding business is just a matter of taste, play around with the numbers and options untill you are satisfied.
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