[MPlayer-users] Alternative 3-pass methods

Jack lt at speakeasy.net
Tue Jun 22 06:49:22 CEST 2004


A few weeks ago, someone made a suggestion of using the following options as an alternative to mplayers buggy 3-pass encoding, and to get around slight sync problems with -oac mp3lame.

	mplayer dvd://1 -ao pcm -aofile audio.wav -vo null
	lame -V 3 audio.wav audio.mp3
	mencoder dvd://1 -oac copy -audiofile audio.mp3 -ovc lavc -lavcopts [...]:vpass=1|2

So I decided to try it, and see if there were any sync problems... and there are.

The DVD I used was Princess Mononoke, a telecined NTSC dvd.  I actually had already ripped this, quite a while ago, with 3 pass encoding on pre3 (I think).  I had no problems when I did it then, and the finished product stayed in sync just fine.  So I figured this would be a good way to try out the new method.

I found that without adding at least -mc 0, every 10th frame is duplicated, and as a result the video lags WAY behind the audio.  Needing -mc 0 is old news, but I've never personally seen it this bad. 

When I add -mc 0 and -noskip, it starts off fine, but very slowly and gradually drifts out of sync.  By the end of the movie, the audio is leading the video by around 1 second.  This makes me think the frame rate is slightly wrong, but I used 23.976 in my first rip of this movie, and had no problems.  Playing with -fps and -ofps isn't really getting me anywhere, but I don't really know how to use them properly in this situation.

Here's the command lines I used for this.  Any help figuring out how to do this properly would be much appreciated, as I would like to do 3 pass encodes without having to deal with frameno's brokenness.

	mplayer dvd://1 -dvd-device /dev/hdc -aid 130 -ao pcm -aofile audio.wav -vo null -vc dummy
	lame -V 1 audio.wav audio.mp3
	mencoder dvd://1 -dvd-device /dev/hdc -dvdangle 2 -audiofile audio.mp3 -mc 0 -noskip -ofps 23.976 -vf crop=720:468:0:4,scale=480:256 -ovc lavc -lavcopts vqscale=3.7:aspect=1.85 -o Mononoke-raw.avi

(that cropping and scaling was really unnecessary for just testing this method, now that I think about it)

-lt




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