[MPlayer-dev-eng] Re: RP: sync problem when switching mpeg1 video streams via pipe

David Toso dtoso at optushome.com.au
Sat Jan 11 16:28:02 CET 2003


Hi Arpi,

Arpi <arpi at thot.banki.hu> wrote:
> > continue to play for about 2 seconds before changing, whereas the video changed
> > immediately. To be clear, during the 25 seconds of the 1st file, the video
> 
> no wonder - have you ever heard/think of audio buffering? :)
> and it's not even in mplayer, it's done by the soundcard (hw or driver).

Ah, ok I didn't think about that. I'll do some more testing, but I thought I had noticed 
that the delay would get longer the more times I changed files. Would that still be 
consistent with HW/driver audio buffering?

> the various sound API's (oss. alsa etc) have various functions to
> clear/reset/query buffers but they are poorly implemented by most drivers.

Assuming it is audio buffering, does mplayer ever clear/reset the soundcard?
Also it only really has to work with OSS/ALSA on EMU10K1 (SBLive!) as that
will be the recommended hardware for the PVR. (because it's all I have to test
with atm :-)

If reseting audio takes 'some time', I may have a further problem. I will have six
mplayer instances running at once, and they all have to change to the next stream
simultaneously. It will be _very_ noticable if one or more don't change at _exactly_
the same time. 

BTW, only the sound from the 'currently selected' movie is actually being played 
at any time (faded in when selected) - if no movie is selected, some default 
ambient menu track will be played.

Thanks for your help Arpi.

David Toso.

PS: There seems to be some problem (in the mailing list software I assume) with 
       replies to messages that have very long subject lines -- for example, I had
       to scan the in-reply-to's in the digest to find a reply to my post, as the subject
       for your reply came out as: "Re: [MPlayer-dev-eng] (Arpi)". It seems that the
       subject in my post was shifted down to a second line, leaving the first line blank.


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