[MPlayer-users] thanks!

Catalin Muresan catalin.muresan at astral.ro
Fri Mar 28 13:25:12 CET 2003


On Fri, Mar 28, 2003 at 01:35:47AM -0500, Yan Seiner wrote:
 > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
 > OK, Thanks everyone!
 > 
 > I now have the ability to take my PAL tapes, run them through my
 > PAL/NTSC tape deck, edit them to cut the cruft out, and play them back!
 > 
 > Wow!
 > 
 > Here's a collection of my *limited* and probably erroneous wisdom. 
 > Hopefully this will be useful to other newbies as a starting point:
 > 
 > grabbing videos from a regular VHS:
 > 
 > mencoder -tv
 > on:fps=29.97:driver=v4l:input=1:norm=NTSC:width=320:height=240:adevice=/dev/dsp
 > -ofps 29.97 -ovc xvid -xvidencopts bitrate=800 -oac mp3lame -lameopts
 > vbr=3 -o movie5.avi

	are you sure that your BT878 card doesn't know PAL so you don't have
to do the conversion ?

 > There's no reason to use a greater than 320x240 resolution on the
 > capture since 240 is the resolution of a VHS tape. (I tried the
 > recommended 352x240 but it came out squished.)  This may be different

	you could try to encode with lavc and use the aspec=1.33 option or
playback with aspect=1.33

 > for S-Video; ordinary composite is 240 lines of resolution.
 > 
 > A word on resolution: if your resolution is not a multiple of 16,
 > strange things will happen.  Like a field of green with your image
 > smushed into the top 3 lines.  Or other, equally strange things.  Why? 
 > I have no idea.  I'm guessing it has to do with the compression used. 
 > For display on a normal TV, make sure your resolution is at a 4:3 ratio.

	MPEG specifies that the image is split in 16x16 blocks which are
encoded, not the image as a whole, so the encoder (or the player ?)
compensates the missing info.

 > For some strange reason, I have to specify a much higher bitrate for
 > cartoons (800) than live action (500) to get comparable quality.  Again,

	try also (for lavc) vhq:v4mv, or some kind of noise reduction (-vop
pp=tn) or something else, also try not to use width=320:height=240, use
instead width=640:height=480 and -vop pp=tn/lb,scale=320:240
(documentation.html - 2.4.3 Examples)

 > I guess this has to do with the compression used.  Or possibly it's an
 > artifact of the PAL to NTSC conversion and the multiple
 > analog-digital-analog conversions that happen with my setup. (analog PAL
 > - digital conversion inside deck - analog NTSC - composite in to
 > computer - digital). YMMV.
 > 
...
 > --Yan

-- 
 Catalin Muresan
 ASTRAL TELECOM
 Internet Department
 Technology Engineer



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