[theora] No quality advantage with two-pass?

[Remco]

[Sorry, we got off-list. Added Theora list again]

On Sat, Aug 29, 2009 at 6:43 AM, Jason Self<jason.self at gmail.com> wrote:
> There are alot of calculations done while encoding. As development on the
> encoder continues, you should expect to see better quality with the same
> file size and/or the same quality with smaller files... Depending on what
> you're encoding. But regardless, either one of those are better results.

For batch encoding, it would be nice to know if a constant quality
level means the same thing for different videos.

If I find a quality level of Q1 to be acceptable for one source, in
terms of video quality alone (so I don't care about file size), will I
find similar results with a quality level of 1 for another source? In
other words: can I trust that Q1 means Q1 for every video?

And, less importantly, if I find a quality level of Q1 to be
acceptable for version 1.1 of Theora, does that mean I get a similar
result for version 1.2 of Theora?

And just out of curiosity, how are the quality levels translated into
an encoding strategy? Are these quality levels mapped to advanced
internal encoder options, or is the encoder basically one big
mathematical equation that takes one parameter? (besides the video
input, obviously)

--
Remco