Fair question. For everyone's benefit, especially Adam Marcus who contributed the patch, I should explain what's going on in this section of the code.
Of course there is some "cost" to every new feature (in complexity and the need to maintain it). x265's rate control is significantly more complex than x264, due to WPP and frame parallelism. At any given point in time there may be 5 or 6 frames in varying stages of completion, and typically you don't want to change the base QP mid-frame. We've also added new features we've added to handle special cases that arise due to frame parallelism (ABR reset, etc.). We're also developing a new CBR variant of ABR with VBV. It is challenging to deliver rock solid rate control under all possible scenarios, and when rate control can't handle certain material you run out of bits somewhere, QP goes through the roof and you get visible distortion. We have a number of important customers who are putting x265 into commercial production, and we get feedback (along with content samples, steps to reproduce, etc.) when x265's rate control doesn't handle a particular combination of settings and content optimally. These customer requests have been driving a lot of the rate control patches/improvements that you've seen over the past months. We weigh the cost against the benefit. We like the basic concept of this patch - the ability to uniquely adapt x265 to different segments within the video title. This type of capability fits in with our long-term roadmap for x265. Let me discuss with the engineering team to figure out when and how we can add this feature. Now might not be the best time to commit this patch, as our rate control lead developer is still working to finish up the new CBR mode. Tom -----Original Message----- From: x265-devel [mailto:[email protected]] On Behalf Of Derek Buitenhuis Sent: Tuesday, December 23, 2014 12:50 PM To: [email protected] Subject: Re: [x265] [PATCH] Basic support for tweaking rate control using zones On 12/23/2014 6:03 AM, Deepthi Nandakumar wrote: > Thanks for your patch. I'm not quite sure any of our regular users need this as of now. We will keep this on standby though - until any requests come in. Zones are fairly popular on e.g. Doom9 and within the the anime community. I don't really understand the point of keeping it on ice until you get a request - is it going to hurt? Cheers, - Derek _______________________________________________ x265-devel mailing list [email protected] https://mailman.videolan.org/listinfo/x265-devel _______________________________________________ x265-devel mailing list [email protected] https://mailman.videolan.org/listinfo/x265-devel
