[mythtv] mplayer + nuv/(mpeg4|rtjpeg) patch

[Jay R. Ashworth]

On Fri, Apr 04, 2003 at 11:06:02AM -0500, Isaac Richards wrote:
> On Friday 04 April 2003 10:43 am, Geoffrey Hausheer wrote:
> > On a similar topic, any idea how difficult it would be to make mencoder
> > WRITE nuv files (likely only MPEG4 would be needed)?
> > I've been working on coding a transcoder into myth so i can record
> > initially in RTJPEG, and transcode to MPEG4, to get a high-quality
> > encoding at high resolution with multiple imputs without swamping my poor
> > CPU.
> >
> > Unfortunately, the encoders/decoders in myth are not really designed for
> > this.  I can extract the audio/video and write it to a file in
> > uncompressed format (by adding some hacks to libmythtv) (I think...i have
> > no idea how to actually display the raw data), but I haven't figured out
> > how the encoder works well enough to maintain sync, and write a valid nuv
> > file.  The encoder in myth is also heavily threaded, which is really not
> > necessary for transcoding, since runtime is irrelevant.  I looked at how
> > ffmpeg does it, and it is pretty straight forward (decode a frame,
> > process frame, encode frame...there is some code to sync video to audio,
> > but it is not bad).
> 
> If you're just going to do straight transcoding from rtjpeg to mpeg4 and 
> keeping things in the .nuv format, this can be done quite easily within 
> libmythtv -- see the commented out ReencodeFile() function in 
> NuppelVideoPlayer.  It's using an older version of the libavcodec API so 
> would need to be updated, and it'll also need to be updated to handle the 
> newer modified .nuv file format I'm using.  But, should be pretty easy to 
> update it.  You don't need to worry about a/v sync at all, since you'd just 
> be doing a straight copy, aside from transforming the video frames into 
> another format and updating the appropriate headers.

This seems the appropriate time to ask *my* pet question:

My sister is a *hardcore* taper (4 decks is sometimes not enough), and
I'm guessing that "1GHz per tuner card" that someone quoted somewhere
in my research assumes real-time reencoding.

I don't much care.

I'd like to build a 6-channel box, likely using CPH-060's (Tview-99's),
since they *spec* to capture at 640x480 (and yes, I know about Kell
Factor).  Could just grab using the card's native hardware compression
(and what *is* that on {that card,the Bt878}, anyway?), and stream to a
pre-allocated set of disk files on their own partition, and then
re-encode and directory the stuff later?

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra at baylink.com
Member of the Technical Staff     Baylink                             RFC 2100
The Suncoast Freenet         The Things I Think
Tampa Bay, Florida        http://baylink.pitas.com             +1 727 647 1274

   "If you don't have a dream; how're you gonna have a dream come true?"
     -- Captain Sensible, The Damned (from South Pacific's "Happy Talk")