[MPlayer-advusers] DVB documentation unclear/outdated
lynx.abraxas at freenet.de
lynx.abraxas at freenet.de
Mon Feb 12 00:23:04 CET 2007
On 12/02/07 00:05:17, Nico Sabbi wrote:
> lynx.abraxas at freenet.de wrote:
> >I think there is a misunderstanding. I am using transcoding here
> >"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
> >encoding which is not transcoding. I'm though not sure if transrating
> >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
> >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
Why is -dumpstream and co in mplayer?
> >I'm referring to this email from the thread
> unsubstantiated science ficton
OK, that's what I feared...
> >>>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
> >since mplayer -demux help yields mpegts fitting to last lines
> >libmpdemux/demux_ts.c but making not much sense to google hit for
> that mail isn't about trandcoding, but simply about dumping (saving)
> the dvb stream to file
Yes, but demux_ts is in its title;)
> >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
> >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
> >mplayer -vo xvidix does work.
> >Contrary mplayer -vo cvidix and 'h' or 'k' make mplayer change the channel
> >when showing the new channel it does not care about any key strokes any
> maybe *during* channel tuning
No, even afterwards when the programme is already displayed and whatever minutes later.
Do You have any idea how I could find out what's wrong there? I don't get any errors. Nor does -v or strace give something suspicious.
> >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 ...
Thanks for all the explanations. It's much clearer now. (except for cvidix + dvb)
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