From: Arpi <ar...@th...> - 2002-11-29 21:01:12
|
Hi, > > > 1) the system clock is the master (i.e. no fiddling with the clock) - this > > > was the behavious before my commit. > > > that seems to be good for dxr3 users and generally for people who > > > want absolutely smooth video playback at the price of possible audio > > > glitches. > > this is also required for people with buggy/broken audio drivers (ie when > > the audio driver reports bad buffering status / delay value (GETODELAY ioctl > > of OSS) - it's more common than we can hope :( > > (no way to do audio clock syncronized smooth playback using such drivers.) > > > Yes there is... at least in xine we have two modes that can be used in > such case, and one of them should give you almost perfect sync: by > probing sound card buffer size to estimate the latency and keeping > audio_out loop most of the time blocked by the write(). Yes, I did it in early (pre-0.18?) mplayer versions too, but select() was also problematic (buggy) with those broken OSS drivers. (there was even a driver which Oops'ed kernel when i used select() on it :)) With threads it can be done without select(), having a thread which keeps blocked by write(), I assume you do it this way. Estimating/measuring buffer size/latency is another nice problem :) > > > 2) the audio clock is the master - that should be good for people who like > > > the audio to be uninterrupted, no matter what. if the streams ptses are > > > bad, then video playback will subordinate to the audio clock (i.e. > > > video will be speeded up or slowed down a bit) > > this is the default method in mplayer too > > i think i noticed that already! :) > > at least in some older versions of mplayer the resampling were not > automatic, so playing videos in a 48Khz-only had quite funny results!! > ;) Yes, it was a feature :) At least the SB16 owners liked it, as the card could do 46.8khz, so playback of 48khz movies went smoothly without needing any resampling. Now it's dropped and libaf kicks in if the card cannot accept the wanted samplerate... A'rpi / Astral & ESP-team -- Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu |