[mythtv] nuv formats for mpeg4? mythtranscode?

[Subbyz]

It's me again too... :)

On Thu, 22 Mar 2007, Chris Pinkham wrote:

> One big issue has to do with the framegrabber video capture cards, sound
> cards, and software encoding.  There are a lot of sound cards out there that
> don't give you exactly the sample rate you asked for, and sometimes video
> frames could get dropped for one reason or another.  The NUV container
> format allows us to have timestamps and periodic sync packets to help keep
> ...

That makes sense for original recordings.  However, after using the built-in 
mpeg4 transcode, wouldn't the transcode have fixed any sync problems in the 
process?  So maybe it would be safe to save the output of that without the 
.nuv container and into a plain avi or mp4?  Or does the builtin transcode 
not fix any sync issues?

My main concern with it is that I am using the transcode to mpeg4 in order 
to be able to store more programs without too significant of a loss in 
quality.  And I'd prefer to only have 1 generation of loss from the original 
high-bitrate DVD-quality hardware-based recording to something that is 
playable as a normal recording under myth, as well as movable to other 
mpeg4/avi compatible devices.

Ah, one other possible issue just occurred to me.  Perhaps the .nuv format 
gives you the ability to do time-stretch without much work?  Or is that not 
necessarily a problem with other container formats as long as the sync is 
good?

> The --mpeg2 lossless side of the transcoder has lots of code in it to
> renerate missing frames, etc. in order to keep the audio and video in sync.
> This code would have to be replicated over to the lossy/NUV side of
> mythtranscode.  Otherwise, your best hope for now may be just
> mencoder -oac copy -ovc copy unless you've got a lot of coding time on your
> hands.

Thanks for the suggestion.  I've tried the mencoder with -oac copy and -ovc 
copy, but for some reason the output from that seems to lose the ability to 
seek within the file while playing.  Neither xine nor mplayer seem to be 
able to overcome the seeking problem.  I've even tried adding the -idx and 
-forceidx flags to mencoder, but it still doesn't seem to work.  Is there 
some other way to enable seeking that isn't apparent?

Thanks.

subbyz