yan at cardinalengineering.com
Fri Mar 28 07:35:47 CET 2003
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!
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:
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
For some reason I have to specify the fps for both the grabber and the
output. I think that's because my deck does a digital conversion from
PAL to NTSC, and somehow puts in a rate of 29.00 fps (at least that's
what the playback says...) This leads to jerky videos.
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
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.
For some strange reason, I have to specify a much higher bitrate for
cartoons (800) than live action (500) to get comparable quality. Again,
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.
For my card (bt878) you have to specify input=1 to get the composite
input. By default it grabs from the TV tuner.
For grabbing DVDs:
mencoder -dvd 1 -vop crop=320:240:54:40,scale=432:320 -ovc lavc
-lavcopts vcodec=mpeg4:vbitrate=500 -oac mp3lame -lameopts vbr=3 -o
The hardest thing for me was figuring out the cropping. I wanted to end
up with a 320x240 resolution. The cropping is done after the scaling,
so first you have to back out what the whole screen resolution is and
then crop to your desired resolution.
BTW, the cropping I use still leaves a slight band of black along top
and bottom. It works for me. YMMV.
There are multiple tracks on a DVD; which one has the movie is open to
question. I still haven't figured out how to get a directory type
listing of a DVD, or if such a thing is possible.
My editing needs are simple: cut the cruft from the front and end of a
captured tape. I tried several programs; all failed miserably except
for avidemux. It works like a charm. So simple even I can use it.
http://fixounet.free.fr/avidemux/ It's only slight glitch is that it
comes as a series of src rpms for my system; 'man rpm' and 'man
rpmbuild' to get instructions on how to build and install them.
avidemux even lets you grab single frames to build your indexes with.
Again, thanks everyone for the software and the help!
/\ /_ o__
o* ~(_) ,>/'_ o__
Yan Seiner, PE (_)\(_) ,>/'_ o__ o__
Cardinal Engineering, Inc. (_)\(_) ,>/'_ ,>/'_
http://www.cardinalengineering.com (_)\(_) (_)\(_)
spam killer code kpwq1jkcsEzdx39gnkVvgycd15ayqq
More information about the MPlayer-users