[MPlayer-users] Mencoder: Changing frame rate (RealMedia to vcd)

Bill Moseley moseley at hank.org
Sat Jan 1 21:23:44 CET 2005

On Sat, Jan 01, 2005 at 03:35:09PM -0400, Giacomo Comes wrote:
> In general going from resolution A aspect B to resolution C aspect D
> requires expand and scale or scale and expand.

Why does it make a difference (other than a bug in some software)?

My basic understanding is you can pick 16:9 or 4:3 so you have to
expand, that is, convert the current image to one of those ratios by
either adding black bars (to keep all the image) or by
trimming/cropping.  Then it needs to be resized to fit the target
format (i.e. 720x480 for dvd).  And then there has to be a flag to
tell the player if it's 16:9 or 4:3.

[What happens after to get the image is shown on my direct view
16:9 TV is a mystery to me.]

> By the way encode2mpeg deals with all these situations. The option
> -mpegfixaspect is your friend.

Yes, very cool.  I've been playing with this sample:


And using this command line:

   encode2mpeg -o STEST -n p -mpegfixaspect pad -imageonly -mpeg -svcd sample.rm

I get a lot of "[mpeg2video @ 0x403b9008]rc buffer underflow" and
other messages.  I'm not sure if that indicates a problem or not.

And I have not figured out how to make the resulting mpeg flagged as
16:9 content.  I've tried this:

  encode2mpeg -o STEST16 -a 3 -n p -mpegfixaspect pad -imageonly -svcd -mpeg sample.rm

BTW -- you recommended 

  encode2mpeg -o MYREAL -n n input.rm -encode 2

doesn't that make a divx intermediate file?  It's that a lossy
operation to go from Real -> divx-> mpeg1/2?

Thanks very much -- the encode2mpeg is a huge help.

Bill Moseley
moseley at hank.org

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