dvbsrc best scaling method

[Luca Santini]

Hi all,
it's my first post on ML.
I'm trying to use gstreamer to reproduce DVB-T streams on an embedded 
system (outputting on fbdevsink). Currently it's unaccelerated, so i'm 
searching the best way to rescale the image... is there a way to ask to 
the source (tv dongle) for a different resolution?

This is my current pipeline:

f=650000000
gst-launch dvbsrc modulation="QAM 64" trans-mode=8k bandwidth=8 
frequency=$f code-rate-lp=AUTO code-rate-hp=AUTO guard=4  hierarchy=0 ! 
mpegtsdemux name=demux ! queue max-size-buffers=0 max-size-time=0 ! 
mpeg2dec ! ffmpegcolorspace ! videoscale ! video/x-raw-yuv,height=420! 
ffmpegcolorspace ! fbdevsink demux. ! queue max-size-buffers=0 
max-size-time=0 ! mad ! alsasink device=plughw:0,0

also.... how to change channels? how to select the right one using pids?

thank you all...
Luca