[mythtv-users] Converting HDTV to SDTV

[Roger Heflin]

Adam Siegel wrote:
> I just replaced my PVR350 with a pair of AVerTVHD MCE A180s in preparation
> for the HDTV deadline.  Yes, I use an antenna - no cable here.  Having two
> cards is great as I can record more than one program at a time.  I had very
> few problems with their install, thanks to this forum.  They are working
> perfectly.
> 
> My front-end units on a couple of the televisions in the house are Hauppauge
> MediaMVPs.  I've used the mvpmc distro for a couple of years now without any
> issues.  However, these units can't process the 1920x1080 mpeg2 stream (not
> to mention network bandwidth issues).  So I need to transcode the
> recordings.
> 
> I can't seem to get a good read on what to use and the paramters for the
> various programs.  I have tried both mencoder and ffmpeg.
> 
> The first thing I do is check to see what resolution the recording is by
> doing
> 
> $w = `mplayer -nosound -vo null -ss 03:00:00 -really-quiet -identify $F1
> 2>/dev/null | grep ID_VIDEO_WIDTH`;
> 
> in a perl script.  If the width is less than 720, the the MediaMVPs seem to
> work fine and no transcoding is necessary.  However if it's greater than 720
> I transcode with ffmpeg
> 
> ffmpeg -i $F1 -croptop 12 -target ntsc-dvd $F2
> 
> I needed to add the croptop because there is some noise that I get in the
> recording (don't know why).
> 
> Anyway, with ffmpeg I have noticed some voice sync problems with the
> MediaMVP.  The picture looks fine.  Playback on a PC using either the ASX
> stream from MythWeb or using MythTVPlayer on widows is fine.
> 
> Appreciate any advise available for a better transcoding method!!!

Search for makempeg2 it is script that I wrote up to do exactly this, 
it uses mencoder to do the conversions.

With a decently fast machine the transcodes are available fairly quickly.