2-pass or 3-pass encode?

[mad_cracker]

I've been wondering wich is better and I've got some topics that I need someone to explain:

- Does 3-pass makes the video lose compressibility?
- Does it make lose quality?
- When should I use 3-pass?
- What does the 3th-pass do?

Thanks in advance.

[martino]

Generally there is very little difference 3 and 2 passes from what I know. 3-pass might be useful if you are encoding a very short clip (think in seconds). Searching Doom9 for "pass" or similar keywords gives pretty interesting results, so I'd go for that if you need more detailed information.

[Dark Shikari]

- Does 3-pass makes the video lose compressibility?
- Does it make lose quality?
- When should I use 3-pass?
- What does the 3th-pass do?

1. No.
2. No.
3. When you have too much time on your hands and don't care about wasting time for little real benefit.
4. Not much.

3-pass doesn't actually help bitrate distribution get much more precise, at least with x264; it makes it more accurate on really long videos, but on really short ones it still doesn't fix the problem of inaccurate target bitrates.

Summary: Don't bother.