[mythtv] MythTV Recording System Future

Isaac Richards ijr at po.cwru.edu
Sat Jul 19 22:32:01 EDT 2003

On Saturday 19 July 2003 08:17 pm, Mike Javorski wrote:
> When I set out on adding the various pieces of IVTV support I had no
> idea the levels of cruft that had to be used to make it work. It's
> crazy. There is little bits and pieces all over the place to make it
> work. I realize this may be partly due to the fact it was added to an
> existing system which dealt with individual audio/video compression
> sources, but yikes..

What cruft?  For the patch you sent in, you modified the mpegrecorder class 
setup routines, the one bit in the overall tv recorder class that sets the 
various recording settings (and chooses the recorder class), and the UI setup 
bits.  It's hardly complicated.  The last two parts could even conceivably be 
moved into the recorder classes if you really wanted to, so everything would 
be in one place.

> Well anyway. I am wondering what the general consensus is out there.
> Should the recording system be made "plug-in" based? I would imagine
> that in future there might be other "special" devices that people will
> want to support, and the current mechanism (though it does work) makes
> it a bit like voodoo.
> Additionally there should be comparative playback/decoding plug-ins
> ones that are designed to deal with different stream types. (as
> recordings should always be stored as some type of stream on the disc)
> this could possibly be done with extensions:
>  .mpg => fmpeg decoder mechanism
>  .nuv => true nuppelvideo decoder mechanism
>  .divx => some DiVX decoder
>  .mtvs => the isaac richards nuv format (MythTVStream)
>  .omf?? => ogg stream format
>  .avi => longstanding though evil stream format

All of these, aside from the original .nuv and .ogm, are already playable by 
mythtv.  I _really_ don't see the point of recording into any other formats 
than what it currently does.  There's tools available to take it out of the 
modified .nuv format, and the added complexity and loss of flexibility to do 
native recordings just isn't worth it to me.  And if you really want 
something playable by other programs without any work at all, just use a 
wintv pvr-?50 like you are now =)

> This system would allow for recording to formats that can be archived
> and viewed on other platforms. Additionally it would support recordings
> that were recorded in one format, and then re-encode them with a non
> real-time encoder to end up with a higher quality file, but still be
> able to view them through the mythtv interface. (something I want is to
> record in Huffyuv then transcode to a multi-pass DivX or MPEG)

You can actually record into a .nuv wrapped huffyuv (or pretty much anything 
supported by libavcodec) file extremely easily (assuming you've got enough 
disk speed/space to keep up).  I just don't have the functionality enabled 
because I _know_ people will start picking random codecs that they shouldn't 
be using and then complain when things don't work =)


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