[mythtv-users] BBC HD stream with latest MPlayer-1.0pre8

[Wander Winkelhorst]

>
> >  Well, as far as I know, the general rule is: if MPlayer can play it,
> > Mencoder can read it and encode to a other format.
> >
> > I never encode to MPEG2, but this should work for encoding it to MPEG4.
> I'm
> > sure encoding to MPEG2 won't be very different:
> >
> > mencoder -mc 0 -oac mp3lame -lameopts mode=0:abr:br0 -ovc lavc
> -lavcopts
> > vcodec=mpeg4:vbitrate 00 -o "$OUTPUTFILE" -quiet "$INPUTFILE"
> >
>
> I substitued 'mpeg4' with 'mjpeg' and successfully transcoded the
> sample BBC 1080i clip I dowloaded from here
>
> http://www.giusberto.ch/hdtv/
>
> (I presume it's the same one mentioned by the OP, since it also
> features David Attenborough and a storm)
>
> into something that plays full speed with picture and sound on my AMD
> 64 3000.  However I have much still to understand.  For one thing the
> transcoded clip is smaller than the original (40MB vs 50MB), so either
> I've lost some of the quality or I didn't get to the end of the clip,


You will ALLWAYS lose some quality if you re-encode to a lossy format like
MPEG2, MPEG4 or MJPEG

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.

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:

mencoder -mc 0 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vbitrate 00 -o
"$OUTPUTFILE" -quiet "$INPUTFILE"

This will allso improve the time required for encoding (because you don't
encode audio at all, you just copy it)

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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