field order Re: [MEncoder-users] remove noise on MPEG-2

[Dieter]

> I'm still trying to get a high quality MPEG-2 video from a captured AVI
> file (miniDV source). The command I'm using to encode is the following:
> 
> $ mencoder -of mpeg -mpegopts format=dvd -srate 48000 -af
> lavcresample=48000 \
>   -vf harddup,softskip -oac lavc -lavcopts acodec=ac3:abitrate=448 \
>   -ovc lavc -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:\
>   vrc_maxrate=9800:vbitrate=4900:keyint=15:trell:mbd=2:dc=10 \
>   -o iso/dvd.mpg /opt/dv4/dv-2006.07.01_22-03-42.avi
> 
> the ouput mpeg file plays on standalone DVD player, but there is some
> noise on motion images; is something difficult to explain with my english,
> but is some shake not present in source file. There is noise on edges of
> objects too.

Sounds like you might have a field order problem.  DV is always bottom
field first.  Mpeg can be either field order, and there is a flag to
indicate which.

I use ffmpeg to convert mpeg to DV.  Unless they have fixed it recently,
ffmpeg gets the field order wrong.  There is a patch on the ffmpeg-devel
list from a few months ago to allow swapping the field order.  Perhaps
mencoder gets this wrong going the other direction?

Hopefully your standalone DVD player can handle either field order
and you just need to switch the flag bit.  Perhaps one of the
mencoder experts here can explain how to do that.