[mythtv] Thoughts on CD/VCD/SVCD burning

Thor Sigvaldason mythtv-dev@snowman.net
Fri, 23 Aug 2002 05:30:39 -0400


All,

	I've spent the last 4 or 5 days trying to figure out a workable way to burn 
disc's of video content from MythTV. I have cobbled together some code to do 
it, but it's far from ready for primetime.

	So .... before I fold anything back into the tree, some thoughts/questions 
for open discussion:

	1. To burn a VCD and/or SVCD compliant disc (ie. something yu can stick in 
another computer, stand-alone DVD player, etc), the machine will need 
processor time. The former requires strict MPEG-1 (video) compliance, and 
needs specific resolutions (NTSC or PAL) to be compliant. The latter also 
requires adherence to standards (MPEG-2) that demand even more processing 
time.

	2. The tools to do this are all readily available. In particular, the 
mpegenc program from the mjpegtools effort will swallow a myth-style 
Nupple-encoded stream and spit out a compliant mpeg-1 or mpeg-2 (for VCD or 
SVCD) stream.

	3. Compliance is not the problem. CPU time is the problem. The logic of "Fix 
Scheduling Conflicts" gets a heck of a lot more complicated when you need to 
allocate CPU time to re-encode content/burn discs. Do you want to not record 
a program because the CPU needs time to encode something you (Nuppel) 
recorded two weeks ago?

	4. One workaround would be to be build a nice web interface to the Myth 
mysql system, and let all encoding/disc-burning happen on another machine. 
That's nice for performance, but greatly hinders end-user simplicity.

	5. Another option would be to let users burn well identified "multi-session" 
CD's that just contain the raw Nuppel-codec'd video. You'd need 1-2 discs per 
half hour, so the whole thing would be more like an offline backup and 
restore operation than a "watch from disc" way of operating.

	The knee jerk reaction is, of course, to allow all of the above. But, if 
Myth is ever (eventually) going to get taken seriously, then the end-user 
options need to be constrained. This is not about power hacking, it's about 
controlling streaming media with a remote that only has 20 or so buttons. 

	I am happy to work on the logic that would extend mythfrontend to the point 
where it understands its computational (as well as time slot) constraints, 
but I'm interested in feedback w.r.t whether this is a good idea before I 
plunge in.


BR,

Thor



	

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Thor Sigvaldason <thor@sigvaldason.com>
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