[x264-devel] Optimized multiple rendition encoding

[BugMaster]

On Sat, 12 Nov 2016 07:32:59 +0000, Eran Kornblau wrote:

> Thanks for your reply! However, as far as I know, 2 pass is about
> 50% slower than 1 pass. So if the highest rendition 
> (which is the heaviest to transcode) will be transcoded with 2
> pass, the whole process will probably take more time
> than it does now. To put it differently - I don't think the speed
> gain in the lower transcodes will compensate for that. 
> Yes, I may get higher quality thanks to the 2 pass, but my goal
> here is to shorten the transcoding time/reduce the 
> resource usage.

If you currently use 1-pass ABR for your encodings you still can use
this method. Only difference would be that you would use result of
1-st pass (which should be done with `--pass 1 --slow-firstpass`) as
end result for this bitrate. This way you will make same number of
passes (bitrates) as you currently do and N-1 of them wouldn't need
lookahead (slicetype decisions, AQ, MBTree) at the little cost of IO
(writting/reading stats-files) and probably would have better quality
then simple 1-pass ABR for all.