Re: [MPlayer-users] Having problems ripping a telecine dvd [León:the professional Director's cut]

[Jonathan Rogers]

D Richard Felker III wrote:
> Second, 16:9 is the aspect ratio before cropping. You need to crop off
> the black borders or encoding quality will SEVERELY suffer. Read
> DOCS/tech/encoding-tips.txt for a good overview of all the issues
> involved, and remember, making a good encoding is a process that
> requires a lot of care, attention, and willingness to learn, not an
> automated "press-the-green-button-and-it-goes" thing.

I had to think about the aspect ratio for a while before I figured out 
how to get it right. The formula I use is:
encoded_ar = (uncropped_ar * cropped_ar) / display_ar

Where:
encoded_ar := the ratio which you supply to lavc or MPlayer
uncropped_ar := ratio of the DVD frame, 1.5 (720/480) for NTSC
cropped_ar := ratio of the DVD frame after removing black areas
display_ar := ratio DVD is supposed to display at, typically 16/9 or 4/3

For one DVD I did recently, uncropped_ar=720/480=1.5, 
cropped_ar=716/258=2, and display_ar=16/9=1.7778, so encoded_ar=2.37. 
The technique I use is to scale the frame (with -sws 2 for high quality) 
to something close to the encoded_ar, and set aspect=encoded_ar as well. 
That way, it will be displayed perfectly by MPlayer, and acceptably by 
other players.

As for the "press-the-green-button-and-it-goes" issue, there are tools 
which do most of the grunt work for you, but mencoder certainly doesn't. 
I used dvd::rip <URL:http://exit1.org/dvdrip/> for a while, but mencoder 
seems to have some advantages over transcode. There are also 
<URL:http://acidrip.thirtythreeandathird.net/>, 
<URL:http://sourceforge.net/projects/kmencoder/> and 
<URL:http://gmencoder.sourceforge.net/>, but I haven't tried them yet. 
As with anything, if you want maximum control, you must understand the 
details, but if you don't want to spend as much time, there are tools to 
deal with the details.

Jonathan Rogers