[MPlayer-advusers] DVB documentation unclear/outdated

[Nico Sabbi]

lynx.abraxas at freenet.de wrote:

> 
> I  think  there  is  a  misunderstanding.  I  am  using  transcoding  here for
> "transcoding between MPEG-2  and    MPEG-4  (partial  decompression)" 

there's nothing "partial" here: a full decompression takes place

> without decoding  to  raw  and then encoding to mpeg4 (as mentioned at the end of DVB-
> doc). If I'm not mistaken decoding to raw and  then  encoding  is  called  re-
> encoding  which  is  not transcoding. I'm though not sure if transrating would
> apply here as well since they are both mpeg but not the same video formats. In
> the  excerpt  it  states  re-encoding  not  transcoding  and so it is for sure
> mencoder's task but not what I am looking for.


re-encoding == transcoding; in this context the only difference 
between the transcodings done by mplayer and mencoder is the direction 
of the output: to file if done by mencoder, to the dvb card if done by 
mplayer

> 
> I'm    referring    to    this     email     from     the     thread     here:
> http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
> 

unsubstantiated science ficton

> 
>>>What  uses demux_ts: -demuxer lavf or  -demuxer mpegts?
>>>
>>
>>isn't the filename clear enough? demux_ts; anyway -demuxer lavf can be
>>used to demux dvb streams, too
>>
> 
> 
> If  one  is  new and unsure about things concerning DVB, demux_ts is confusing
> since  mplayer  -demux  help  yields  mpegts  fitting   to   last   lines   of
> libmpdemux/demux_ts.c  but  making  not  much sense to google hit for demux_ts
> http://www.arcknowledge.com/gmane.comp.video.mplayer.user.dvb/2006-10/msg00031.html

that mail isn't about trandcoding, but simply about dumping (saving) 
the dvb stream to file

> So  I'm  still  wondering  if  anyhow  one  can use demux_ts with DVB-input to
> achieve transcoding in the way I discribed above? So that I  end  up  with  an
> mpeg4-file without re-encoding.
> 

as I wrote, re-encoding/transcoding - however you call it - is still 
done 100% by your cpu: there's nothing done by the dvb card, not even
the mpeg2 decoding
(although it's possible to make the dvb card to the actual decoding 
and use mencoder to read the uncompressed audio and video streams
from the card's output: tv://, but I would never bet on the synchrony)


>>xvidix does accept 'h', 'k' and shows the osd menu. I use it every day
> 
> 
> Sorry, my mistake. gmplayer -vo xvidix and 'h'  or 'k'  make  mine  crash  but
> mplayer -vo xvidix does work.
> Contrary mplayer -vo cvidix and 'h' or 'k' make mplayer change the channel but
> when showing the new channel it does not care about any key strokes any  more.

maybe *during* channel tuning

> I  think this is somehow connected to dvb:// since 'h'  or 'k' work forever if
> I use them with v4l2 mplayer -vo cvidix tv:// -tv ...
> 

-- 
"Without a frontend, mplayer is useless" - someone in mplayer-users