[MPlayer-dev-eng] Do decoders have a stream ?

Arpi arpi at thot.banki.hu
Wed Aug 27 11:34:24 CEST 2003


> > > > > So what about implementing decoding ahead in one process into G2 ;-)

> > > > cannot be done unless your hardware supports timed display of frames

> > > Huh, cannot be done? =)

of course i meant cannot be done (well) in one process/thread.

> Two threads, agreed.
> The use of it would probably be to have a more precise timing, IMHO.

yes i know its use in 2+ threads, of course.
i only dont know what is its use in one thread, ie. just delaying video
stream by a few frames. maybe it could help framedrop a bit, by giving more
chanse to always skip B frame.

> I don't think that decoding of say five frames in a row consumes equal amount
> of time on each decoded frame, the time spent decoding will vary from frame
> to frame. This means that the decoding process of one frame might consume more
> time than what we have left until next frame is supposed to be displayed.
> But we don't know when and if that is, it's up to the decoder to consume cpu 
> time. And unless every codec is checked to not consume too much cpu, the
> result 
> will (on some low end cpu:s) be jerky, not very jerky, but still jerky video.
> By placing it in a separate thread you allow the time spent in decoding of one 
> frame to vary, the important thing is the average. 

i know, but it only happens on slow (boundary) cpus, not being able fast
enough to decode any frame in less than 1/fps time.
this issue was addressed by mplayerxp fork (by Nick), with less than more

A'rpi / Astral & ESP-team

Developer of MPlayer G2, the Movie Framework for all - http://www.MPlayerHQ.hu

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