[MPlayer-users] Re: Problem with playing mpeg2 files smoothly

[Jonathan Rogers]

Martin Grim wrote:
> I am facing problems with playing mpeg2 files. About every second the video 
> stops for a very short amount of time. Funny thing is that when replaying the 
> same mpeg2 file, the problem doesn't reoccur for the part of the file which has 
> been played before.

This type of problem seems to be the bane of MPlayer. For quite a while, 
I wouldn't use it play DVDs, since it would be jerky. Ogle and Xine did 
fine. Now, MPlayer can play DVDs just fine, but I'm not certain what 
changed. It might have been nothing more than the default -cache value, 
since I wasn't very familiar with MPlayer back then.

I still get they jerkiness you describe when playing a movie from a 
mounted ISO9660 filesystem on a CD-ROM if the drive doesn't have DMA 
turned on, regardless of -cache size. Oddly, it can be smooth playing a 
VCD (with an OGM, not a real VCD) in the same CD-RW drive (DMA is still 
off).

I have another drive (a DVD-ROM) that has DMA turned on. It works well 
playing movies from ISO9660 filesystems, but is jerky with the faux 
VCDs. I can only conclude that the Linux CD driver and IO subsystem must 
be using very different buffering strategies from MPlayer and the 
differences between my two drives are bringing this out.

MPlayer's buffering strategy seems too brittle, since playback so easily 
becomes jerky. Xine seems a bit better in this area. Maybe some renegade 
developers from each of the projects should come together to produce an 
unholy hybrid. ;)

Jonathan Rogers