[mythtv-users] Nuvexport and Multipass

[Patrick Reynolds]

On Mon, 8 Mar 2004, Chris Petersen wrote:

> > How can I setup nuvexport to do multi-pass?  Rather then guess at what the
> > bit rate should be I'd like to just run nuvexport, have it figure the best
> > bit rate, and then have it transcode for me.  Any ideas?
>
> multipass what?  I don't think any of the linux mpeg2 encoders support
> multipass.

nuvexport can spit out DivX using ffmpeg.  ffmpeg supports two-pass
encoding, though AFAIK it won't "figure out the best bit rate" for you.
Two-pass encoding will just make better use of whatever variable bit rate
you give it.

> Either way, I think that in order to support multipass encoding,
> mythtranscode would need some major updating to act as a frame server,
> not just a fifo stream.

I don't see why.  nuvexport currently calls
  mythtranscode <options> &
  ffmpeg <options>
Why not change that to
  mythtranscode <options> &
  ffmpeg <options> -pass 1
  mythtranscode <options> &
  ffmpeg <options> -pass 2
...?  All ffmpeg requires is that it get the same stream for each pass.
Presumably mythtranscode can do that.

--Patrick