[MPlayer-users] will mplayer do a 3:2 pulldown on 24 fps video when ofps=29.97?

[mplayer at interlinx.bc.ca]

On Thu, Feb 20, 2003 at 02:03:19PM -0800, Brian Craft wrote:
> 
> Check CVS. I believe I saw some code for that.

Cool.  It was in the last 2 or three VFs added.  Is it a true 3:2
pulldown, or just a duplication of 1 in 4 frames?  If you don't know,
no matter, I will go look at the source.

> I don't think detection is a problem.

No, indeed it's not.  It's just a comparison between the fps of the
video material and what the user has requested the ofps be.  That is
why I suggested a nice mnemonic to make it explicit that 3:2 pulldown
should be used for 24 frames/s material rather than some mathematical
based frame repeat rate (i.e. repeat 1 out of 4 frames).

> This is clearly marked in the mpeg
> headers -- that's how a hardware dvd player knows how to convert 24fps
> material.

Right.  But the hardware DVD player can assume the ofps.  MPlayer
cannot.  -ofps=ntsc would tell it that the output is truely an NTSC
televsion set.

On Thu, Feb 20, 2003 at 05:21:30PM -0500, D Richard Felker III wrote:
> 
> It will not be automatic, since 99% of users do not want this
> ugliness.

No?  It's what they are used to when converting 24 frames/s -> 59.94
fields/s.

> However, -vop telecine might do what you want.

As Brian Croft has indicated.  I will check the source for it and test
it out to see if it's really 3:2 pulldown or just a duplicate frame in
4.

> MPlayer does
> not officially support increasing the fps, but if you're using a -vo
> driver with vsync support (mga_vid) or DVB output,

I am.  dfbmga.  I don't think any patches have been sent to to support
this, because to do it effectively you have to display and wait for
vsync in a separate thread (or starve the demuxer/decoder thread) and
we all know what A'rpi thinks of threads.  In fact I have been meaning
to bring up this issue here for a while.  Maybe my next message...
:-)

> it'll probably work
> acceptably well.

I will give it a try.

> Personally, I think telecine is horribly evil and that displaying
> every 4th frame for twice as long looks better than showing two frames
> a whole 1/24 second apart at the same time...

I guess this is where subjectivity comes into play.

> Eventually, mplayer probably will have a -ofps option like you
> describe. This will make it work with all -vo's, but you'll still need
> -vop telecine if you want telecine output.

The only problem I have with having to specify -vop telecine is that
I have to select when to use it depending on whether the video
material is 24 frames/s or not.  This sucks when you are using MPlayer
in a PVR like project where material can be both 24 frames/s and 59.94
fields/s.  If -vop telecine was smart enough to step out of the way
when it's not needed (source material is already 59.94 fields/s) that
would be fine though.

b.

-- 
Brian J. Murrell
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