[MPlayer-users] too SLOW to play HD file

[Reimar Döffinger]

On Sun, Apr 05, 2009 at 07:12:47AM -0400, The Wanderer wrote:
> Oliver Seitz wrote:
> 
> > Am 05.04.2009, 09:39 Uhr, schrieb Rilawich Ango
> > <maillisting at gmail.com>:
> >> When I use mplayer to play 720p (HD file) movie, it flickers so
> >> much with the following message. What to do to make the movie
> >> playing smoothly? ango
> > 
> > It looks like mjpeg codec.
> > 
> >> VIDEO:  [jpeg]  1280x720  24bpp  30.000 fps    0.0 kbps ( 0.0 kbyte/s)
> >> ==========================================================================
> >> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> >> Selected video codec: [ffmjpeg] vfm: ffmpeg (FFmpeg MJPEG decoder)
> >> ==========================================================================
> > 
> > That in fact is not a video codec, but one still picture after
> > another. It's got some advantages to use when cutting and assembling
> > videos, but it's not a codec made for smooth playback. Due to the
> > immense data rate mjpeg needs, I presume it's just data can not
> > travel through your system fast enough. If you have to use mjpeg for
> > playback, go buying several of the fastest harddisks (like 10000rpm
> > types) and connect them in RAID0 or RAID5 array. That might give
> > bandwith that can cope with mjpeg.
> 
> Wouldn't storing the file on a RAM disk potentially also work, if disk
> throughput is the problem?

A little trick: use something like
-cache 131072 -cache-min 40
(assuming you have at least 128 MB RAM free).
The last values on the status line then tells you how full it is.
It should start at 40%. If it reaches about 1% and only then starts
stuttering your disk is too slow.
If it increases up to about 50% then your disk is plenty fast enough.