[mythtv-users] Converting shows to PDA suitable format

[Paul V. Gratz]

On Friday 25 November 2005 04:32 pm, ffrr wrote:
> I am fairly new to converting video, so I have been trying to discover
> the best way to convert my recordings (PAL mpeg-TS from a DVB-T card) to
> a small format suitable for my Palm Tx PDA.
>
> Firstly, I have read that divx is a popular format and the TCPMP player
> on the palm will play it.  Is xvid the same thing? What's the
> difference?  Any other suggestions for a target format?
>

I have a treo 650 and I've encoded a few shows for it.  I have been
using mencoder to encode it to the built-in lavc endcoder for divx.
In my understanding divx is an early implementation of mpeg4 (prior to
the release of the standard). Xvid is another. I'm not sure what the
relative differences are but I think they more or less amount to the
same kind of quality per bitrate. Now that mpeg4 is out I think they
both produce legal mpeg4 output.

> OK, so I have experimented with nuvexport.  Unfortunately, under
> Knoppmyth R5A22, nuvexport with ffmpeg seems to be broken, so I tried it
> with --transcode and chose xvid format and a screen width of 240 (a
> suggestion as a reasonable compromise in quality and size).   The show I
> am converting was 3.9GB in size.  The problem is, on my mythbox, which
> is only a 800MHz celeron, it has been over 12 hours, the target file is
> 200MB and it's still not finished !
>
> I tried running transcode manually from the command line on a faster
> (non-myth) machine I have.  It's a 2.2GHz sempron.  I used this command
> line
>
> transcode -i in.mpg -V -x mplayer -y xvid4,xvid4 -Z 240x160 -E 16000 -b
> 48,1,7,1 -w 150 -f 24,2 -o out.avi
>
> but it still is going slow (<20 fps)
>
>
>
> So, I guess I am hoping for some suggestions on better ways to do this?
>

I get much better performance using mencoder (part of mplayer). Its
something like 15-20 minutes to encode a 1 hour program on my P4 2.8Hz
HT machine.  I use mythtranscode to give me the raw *.nuv file then I
run mencoder on that file to re-encode for my palm machine. Here is
the mencoder command line I use:

mencoder -o outfile.avi -aspect 4:3 -ovc lavc -lavcopts 
vcodec=mpeg4:mbd=2:turbo:vbitrate=300:aspect=4/3:acodec=mp3:abitrate=96  -oac 
lavc -vf-pre pp=lb -vf scale=320:200 -af volnorm  infile.nuv    

Replace outfile.avi and infile.nuv with the input and output files you
want.  The resultant file is ~150MB for 1 hour.  The quality is very
high so you could probably halve the 300kbs bit rate and still have a
usable video if you want smaller files.

The assumption is that you are going from a full screen TV program to
a full 4:3 aspect ratio output file.  You can get slightly better
quality if the program is 16:9 and you crop it but it may be more pain
than its worth (look at the mencoder man page for the info on
autocrop).





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