Can heavy load on a machine affect FFmpeg output quality?
Hello guys, We are running a transcoding server on top of FFmpeg, where in principle the machine can get quite busy in more than 1 concurrent job is submitted. Is it possible that a machine under heavy load might affect the goodness of FFmpeg transcoding output? In other terms, is a video transcoding a function of the load of a machine at a give time? We have given ffmpeg max priority with “nice -20”, if that matters. Thanks for you patience! Alfredo
Hi, Alfredo, On Thu, Apr 30, 2015 at 12:52:58 +0200, Alfredo Di Napoli wrote:
Is it possible that a machine under heavy load might affect the goodness of FFmpeg transcoding output?
Technically: no.
In other terms, is a video transcoding a function of the load of a machine at a give time?
Speed of transcoding is, so if you rely on real time transcoding, it will affect your result, because it possibly can't be delivered in real time. If the OS is stable, and you don't care for performance impact, everything should be fine. The only affects I can think of are either memory corruption on the machine, or (at least speaking for Unix) ffmpeg being killed by the operating system (kernel, OOM handler) if memory runs low. But those can be general issues of heavily loaded servers, not restricted to ffmpeg. Moritz
Am 30.04.2015 um 12:52 schrieb Alfredo Di Napoli:
Hello guys,
We are running a transcoding server on top of FFmpeg, where in principle the machine can get quite busy in more than 1 concurrent job is submitted.
Is it possible that a machine under heavy load might affect the goodness of FFmpeg transcoding output? In other terms, is a video transcoding a function of the load of a machine at a give time?
no, otherwise the same question and answer would match *any* software data in -> data proceeded -> data out how long each piece takes: it don't matter
Le primidi 11 floréal, an CCXXIII, Alfredo Di Napoli a écrit :
We have given ffmpeg max priority with “nice -20”, if that matters.
Note that "nice -20" is short for "nice -n 20", that means more than the max niceness, or in other words the min priority. (That is, assuming the process starts at nice 0; since the argument to nice is an increment, it the process starts with a niceness <-1, it will not reach +19 by adding 20.) renice, on the other hand, accepts a bare priority argument, and therefore "renice -19" really means lowering the niceness. Obviously the first developers who implemented this wanted to have a good laugh. Regards, -- Nicolas George
participants (4)
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Alfredo Di Napoli -
Moritz Barsnick -
Nicolas George -
Reindl Harald