Originally Posted by scowl
Two pass encoding is superior because it allows the encoder to allocate extra bits for frames that benefit with extra bits. Are you saying that all frames in an encode need exactly the same number of bits?
No, I said that unless you have a specific target size one pass constant quality
encoding is superior, for exactly the reason you cite. 1 pass CQ allocates bits as needed to maintain quality. The second pass then goes through and robs bits from some scenes to make the video fit the target size. Neither is a constant bit rate method (the least desirable option).
I've made A/B frame comparisons between the original and my encode and can find no significant differences. I really am able to get HD material recompressed in nearly identical quality at DVD bit rates.
And that's what I said. Your perception is that there's no difference. If you are happy with the result that is what matters. If you take a screen shot of an original frame and a negative of the exact same frame from the compressed version and combine them I guarantee you'll see artifacts.
Perhaps your belief that a second pass isn't necessary is preventing you from seeing the benefit of the second pass. That's commonly called the placebo effect.
Again, no. I don't use a second pass because I'n not concerned with fitting a video to a certain size. I store movies on hard drives, which are significantly cheaper per GB than dual-layer DVDs and a lot more convenient.
Yes, they were recompressing higher bit rate source for a lower bit rate medium. So what are we doing when we recompresss an HDTV source to fit onto a DVD? We are recompressing a higher bit rate source for a lower bit rate medium.
It's the same thing.
Finally, I did ask if DVD was your choice of storage, and apparently it is.