On Thursday, June 29, 2017 6:56:51 PM CDT shalin wrote: > Cley Faye wrote > > > More to the point, as far as I know, ffmpeg will not do parallel treatment > > on either input or output, as you deduced. It certainly is doable, but > > don't seem trivial to implement in the ffmpeg CLI tool itself since that > > tool must handle various cases, and introducing (more) special cases would > > add complexity for not much benefits. > > > > You should look in using the various ffmpeg libraries directly; with that > > you could probably write it to decode once, encode multiple time. But > > unless you have shockingly similar settings and unlimited processing > > power, > > you'll most likely stall some of your encodings while other catch up with > > them. I don't know how well ffmpeg libraries handle multithreading (I > > suppose fairly well since most of it's operations are based on context > > structures) but you'll have to do a fair amount of synchronization by > > hand. > > Thank you for your answer to my original question. So from this, I am > assuming that ffmpeg in its current form doesn't support output level > parallelism. Actually I have 'shockingly' similar transcodings to perform on > a given input stream (I need to crop different parts of the input video and > encode them at same bitrate and also cropped parts are same in size for > each stream). With that each encode should roughly run at the same rate and > I believe multithreading should be really helpful.
All this is possible but you need to do a lot of reading. Starting with input mapping. http://www.ffmpeg.org/ffmpeg-all.html#Advanced-options It couldn’t hurt to read up on how anonymous pipes work in a posix shell, as well as other shell related concepts. -Reuben _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
