x264's 1-pass VBV

[Inventive Software]

As I understand it, x264 had a 2-pass VBV patch commited not so long ago. This got me thinking about how the hell 1-pass VBV is so broken (not quite so now), in that I read a while back about it going over the max bitrate or buffer size. So I thought about something. Please bear with me. :)

The 2-pass VBV patch scans the 1st pass stats file for VBV overflows and corrects them. That's fine for 2 pass. For one pass, what if at each second the buffer was scanned before output and frames re-encoded so they're under that buffer?

[Dark Shikari]

You can't re-encode frames in threaded mode, and the only practical use of 1pass VBV is for realtime broadcast encoding of some sort, which requires threading.

1pass VBV is quite good now, to the point where its definitely practical for broadcast usage (and it better be, given that that's what we're doing with it).