[MPlayer-users] 2-pass encoding to DVD: how to maximize quality?

[Rich Felker]

On Sun, Oct 30, 2005 at 07:10:42PM -0500, Norman Ramsey wrote:
>  > On Sat, Oct 29, 2005 at 10:02:40PM -0400, Norman Ramsey wrote:
>  > > I'm a bit lost in a maze of command-line options.
>  > > I have some HD data streams (720p and 1080i) which
>  > > I wish to transcode for burning onto a DVD...
>  > 
>  > I really doubt 720p is 30fps. 
> 
> The ATSC standard says it should be.  Here's what ffplay reports about
> a saved mpeg-2 transport stream:
> 
>  Duration: 03:37:56.2, start: 6352.220978, bitrate: 16433 kb/s
>  Stream #0.0[0x34]: Audio: ac3, 48000 Hz, stereo, 384 kb/s
>  Stream #0.1[0x31]: Video: mpeg2video, yuv420p, 1280x720, 59.94 fps, 16800 kb/s

This tells you nothing. It's always nominally 30 fps but it's really
60 fields/sec or 24 fps telecined unless you're dealing with ((very
very rare) real 30 fps content.

>  > mp2 audio is not necessarily NTSC DVD players. Use ac3.
> 
> Interesting.  I've been recoding since some of the audio I capture
> (from terrestrial broadcast) is quite badly damaged, and I worry about
> throwing off the hardward DVD player.  But I guess I could recode the
> ac3 rather than just copy?

Yes.

>  > > You'll note the single pass and the hard-coded
>  > > 'vbitrate', which is definitely achieving
>  > > suboptimal results.  Any suggestions would be
>  > > appreciated.
>  > 
>  > Worked fine for me.. maybe your video is bad and needs filtering to
>  > correct it..?
> 
> Sorry, I meant 'suboptimal' in its precise technical sense of 'not as
> good as possible' rather the more common 'not good'.  Translated into
> plain language, my video looks OK (not great compared to hi-def, but I
> suspect it will look fine on a standard TV), but I'm not using all the
> bits that are available on the DVD.  If I could, I'd rather those bits
> were carrying video instead of just sitting unused :-)

Then don't set the bitrate so low (4000). DVD can use up to 8000 or
9000 kbit/sec, I forget the exact amount. Set the max rate and buffer
size accordingly for DVD and then set vbitrate to the exact rate that
will fill the whole DVD, then use 2pass encoding.

Rich