[mythtv] gmyth livetv transcode support

Melunko melunko at gmail.com
Thu May 17 20:18:04 UTC 2007

Hello stuart,

We use gmyth-cat to read livetv content (or recorded programs) from backend
and forward to standard output. Them we "inject" this data to mencoder to be
transcoded to a suitable format and muxer. Afterward we stream the data via

The piece of SW that join all together is the gmyth-stream written in
python. The advantages of this solution is that gmyth-stream can be launched
in any machine. It does not need to run on mythtv backend machine nor video
player machine. I will try to describe my setup:

*** Install svn version of mencoder
$ svn checkout svn://svn.mplayerhq.hu/mplayer/trunk mplayer
$ cd mplayer
$ ./configure
$ make
$ sudo make install

-> This is needed because in the svn version they fixed some problem to
write data to stdout. Older versions do not do that.

*** Install gmyth and gmyth-utils packages.
$ svn co https://svn.sourceforge.net/svnroot/gmyth/trunk/gmyth gmyth
$ cd gmyth
$ ./autogen.sh
$ dpkg-buildpackage -rfakeroot -uc -us -b
$ sudo dpkg -i ../gmyth_0.3_i386.deb ../gmyth-utils_0.3_i386.dev

-> This should play livetv:
$ gmyth-cat --hostname=backend_ip --port=6543 --channel=13 | mplayer -cache
500 -

*** Check-out and run gmyth-stream
$ svn co https://svn.sourceforge.net/svnroot/gmyth/trunk/gmyth-streamgmyth-stream
$ cd gmyth-stream/server/0.2
$ python gms.py

Now we can test if the gmyth-stream is working
$ mplayer "http://transcoder_ip:40000/stream.do?transcoder=mencoder&type=myth&uri=backend_ip:6543/livetv/?channel=13<>"

change transcoder_ip, backend_ip and channel num (13 in the example)

- By default the transcoder sets are: output_width=320,output_height=240,
but you can pass different values in the URL.

So, please, let me know if it works. We have a big problem right now, when
mythtv backend changes the recording file after about 30minutes of playback,
it sends a BACKEND_MESSAGE. We are handling these messages, but it is not
working 100%, maybe one of you could help.


On 5/17/07, stuart <stuart at xnet.com> wrote:
> Hi...
> Melunko wrote:
> > Hello there,
> >
> > I am part of the team that is developing gmyth library. We have had
> > interesting results to access several mythtv backend content remotely
> > and one relevant contribution was the livetv transcode solution we had
> > made based on gmyth, gmyth-stream and two different transcode engines:
> > mencoder and gstreamer. This set of SW allow us to play mythtv channels
> > remotely in any format we would like. This is particularly relevant for
> > small linux based devices with wlan capability that could consume Mythtv
> > content straightforward.
> >
> > We have tested this solution in our analog TV environment and it would
> > be very valuable to us if someone could try this solution in another
> > environment and contribute to gmyth. So, please, if anyone is interested
> > in this topic, be our guest.
> >
> >
> > BR,
> > Hallyson Melo
> Interesting - let me ask so I can paste the pieces together in my mind.
>   Are you saying this new feature drops in place between the mythtv back
> end and a client to transcode the video?  So, for example, an mvpmc.org
> capable MediaMVP box (which can not handle the high BW of HD TV) can be
> detected and supported by offering it programs that have been transcoded
> to NTSC like BW?
> I have this set up several times over and have been wondering how to go
> about creating the Mythtv code to detect and support such clients!
> Tell me how to test your code and I'll set up a test.
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