[MPlayer-users] Scaling and expanding when encoding tv
D Richard Felker III
dalias at aerifal.cx
Wed Dec 15 16:24:55 CET 2004
On Tue, Dec 14, 2004 at 09:29:10PM -0800, Barton Bosch wrote:
> D Richard Felker III wrote:
> >On Tue, Dec 14, 2004 at 12:36:52PM -0800, Barton Bosch wrote:
> >>D Richard Felker III wrote:
> >>>>Is this caused by the 29.97 frame rate? How do you all deal with
> >>>>this? Would it be better to set the tv card's capture rate to 25 or
> >>>>27 in the -tv options? To set the fps to 25 or 27 in -lacvopts? Or
> >>>>maybe dealing with it on playback with the general mplayer -fps option?
> >>>Never set the framerate to anything other than the actual correct
> >>>framerate, in this case 30000/1001 aka 29.97. Anything else will give
> >>>horrible results.
> >>Ok, so is it necessary to pass the frame rate to the tuner card or
> >>mencoder to get optimal results? I've noticed that in the intial
> >>output, mencoder reports the frame rate as 29 fps and that in the
> >>status line (after it settles out) it reads 30 fps.
> >This is NOT the framerate of the movie, it's the rate you're encoding
> >at, i.e. it's measuring encoding performance. And it's rounded to the
> >nearest whole number anyway..
> Which ?this? are you referring to? The status line, i.e.:
> Pos: 62.7s 1878f ( 0%) 30fps Trem: 0min 0mb A-V:0.000
This line above.
> or the initial output, i.e.:
> [V] filefmt:9 fourcc:0x32315659 size:640x480 fps:29.00 ftime:=0.0345
This is VERY VERY BAD!!! Where did the 29.00 come from?!? Are you
using MPlayer 0.92 or something still??? There was a bug like this
once, but it was fixed a long time ago. This is definitely why you're
getting bad choppy output.
> That is what the two instances of an fps stat look like if I do not
> specify an fps value to the -tv option of mencoder. The somewhat
> jumpy playback caused me to find and throw the -identify option;
> it's fps stat on a file encoded without specifying an fps rate looks
> The -identify option does not round to whole numbers, correct? So
> the file is @ 29 fps and not the 29.97 of the original broadcast?
> Would this cause playback to be a little jumpy/look like frames had
> been dropped?
> So what are the best options for recording tv at less than full file
> size (either compressed or scaled or ?) so as to encode them to
> dvd/mpeg2? I'd just -ovc copy the 640x480 29.97 fps signal to disk
> but >1GB/min is a stretch.
Try huffyuv or ffv1 if you insist on lossless. Otherwise mjpeg with
qscale=1 is a good choice.
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