On 12 May 2015, at 15:50, Werner Robitza <[email protected]> wrote:
> On Tue, May 12, 2015 at 3:16 PM, Henk D. Schoneveld <[email protected]> > wrote: >> >>> On 12 May 2015, at 13:50, Werner Robitza <[email protected]> wrote: >>> >>> On Tue, May 12, 2015 at 11:47 AM, Henk D. Schoneveld <[email protected]> >>> wrote: >>>> Would you be so kind to explain why to NOT use the crf option? >>> >>> CRF is essentially a constant quality mode, which results in variable >>> bitrate depending on the spatiotemporal complexity of the scenes. >> Your goal is max quality within a given link-capacity I assume. >> Upfront choosing an arbitrary bitrate to achieve max possible quality seems >> sub-optimal/contradictionary to me. >> A. to many bits for talking heads >> B. to few bits for action dominant events. > > Yes, but that's still what's typically done, unless you choose a CQ > encoding type with a max-rate (which is what libvpx recommends too). But libvpx is much less efficient than libx264 for the same quality. > > You should've mentioned that you're experienced with this -- otherwise > I would've given a different answer. Hm what difference does it make if I know a little bit more or less to how/what you’re answering ? Another option to ‘optimise’ quality for a given bitrate is to use anamorphic encoding. I know YouTube doesn’t accept that but all modern players I know of handle it without any problem. For 720p I use -s 880x720 which works for me pretty well. With this you’ll get a reduction of (1280-880)/1280=31% in needed bits for very reasonable quality. At least a lot better then reducing the bitrate by that % and using 1:1 ie. -s 1280x720 encoding. > >> I see the difference between the methods, but I don’t really understand what >> it’s trying to tel me. What does the X-axis say, total stream-size/#frames/ ? > > It's the frame number (index) in a 3 minute sequence. > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
