[MEncoder-users] Ripping dvd to mp4

[Erik Slagter]

RC wrote:

>> I'm saying that mencoder cannot hardcode subtitles coming from a DVD 
>> (mpeg program stream) while transcoding without the use of several
>> steps  involving temporary files holding the subtitles.

> I haven't the slightest idea what could possibly make you believe that.

Some people at the devel mailing list, like I said before. But maybe in 
the meantime mencoder has been enhanced with this functionality. See the 
other messages.

>> But as said before, mencoder cannot handle B-frames in mp4 (nor any 
>> other lavf-container). This can be worked around using elementary 
>> streams and then mux using gpac, but this can and will sooner or later
>>  screw up your a/v sync because timestamps are lost. That's why I
>>  really want to have one single program that does it all in one pass.

> MP4Box doesn't need elementary streams.

In theory: indeed. In practice: it tends to choke on various containers. 
All of my transport streams make mp4box segfault and large mp4 files 
also tend to do unsane things to mp4box. And I'd rather not use avi 
files if you don't mind, especially when big.

> Seperate A/V streams doesn't inherently mean losing sync.

In practice it does. For example: if you rip part of a DVD, the audio 
and video will be skewed (this more or less follows from the 
requirements on DVD's). With the timestamps, this is no problem. Without 
the timestamps you're screwed. Sometimes this even happens when copying 
a full DVD.

Same goes for transport streams received by DVB, they tend to miss a 
video or audio frame once in a while. Without the timestamps, you're lost.

Once I had a "solution" involving projectX, which indeed guarantees that 
you can use the elementary streams without a/v sync issues, BUT the 
timestamp-straightening algorithm appears to be a little bit too 
aggressive, so it constantly keeps dropping and duplicating frames when 
the timestamps are just a little bit off. This is annoying in panning 
scenes. Also I don't like java apps for various reasons :-/

Anyway, to cut a long story short, there doesn't seem to be the 
"elegant" solution to my problem I was hoping for. Maybe mencoder might 
help a bit, I will have a look at this.

Sadly most countries audio-dub their DVD's so there is little interest 
in subtitling by the developers of multimedia applications.