[MPlayer-users] Problems with NTSC - summary

[Martin Pavon]

On Fri, Nov 08, 2002 at 11:41:36AM +0000, Dominik Szczerba wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> >
> >
> >Are you sure yours dvds are ntsc 29.97? 
> >  
> >
> well, that's what mplayer says.
> 
> >I remember I had this problem when I begun with mencoder. If I played the vob
> >with mplayer, it said 29.97 fps. When I passed this value to mencoder I got
> >a file shorter than I calculate... Some day I proved the vob with transcode 
> >(a fine piece of software, but has serious problems with A/V sync with ntsc
> >dvd) and it said fps: 23.976 which seems the standar for no television movies. 
> >I tried with ofps=23.976 and the expected size and the final size of the files
> >became very closed. 
> >  
> >
> how close? not with 25/23.976 by some chance? ;) Can you still check it, 
> do you still have the files?
> 
> ds
> 

Hi Dominik !!!!!

I haven't the old files, but I made some test for you with a newer. In 

http://mate.dm.uba.ar/~mpavon/tmp 

You can find the following files:

sample.vob (20mb)
test.sh
23.976.log
29.97.log

The first is the vob sample for the test. I encoded it with a target size
of 2mb. I estimated the videobitrate with the formula

target_size*1024^2*8/(duration_in_sec*1000)

Duration is 26.7 sec so I got 628 approx.

For the test I used test.sh first with OFPS="-ofps 23.976" and output
ofps-23.976.avi and later without it (so I believe mencoder used 29.97 as it 
said) with output ofps-29.97.avi. 

The size of the resulting files is:

-rw-r--r--    1 m        users     2104052 Nov  8 23:19 ofps-23.976.avi
-rw-r--r--    1 m        users     1663710 Nov  8 23:21 ofps-29.97.avi

As you can apreciate, 23.976 reach the target size and 29.97 is noticiablely
smaller.

23.976.log and 29.97.log are a cut & paste from the Eterm after the second
pass. You can see the the difference in the duplicate frames between 23.97 
and 29.97, I guess this is a sign the that 29.97 fps is wrong 

Regards,

Martín
-- 
Martín Pavón
martin_199ar at yahoo.com.ar
http://mate.dm.uba.ar/~mpavon/