Ripping copy-protected DVD with mpv

11/02/2014 update:

See this post for issues, explanations, and more.

10/25/2014 update:

I'm such an idiot. vobcopy is the real, hassel-free way to go.

brew install vobcopy

Then, with the DVD mounted,

vobcopy without any options will copy the title with the most chapters into files of 2GB size into the current working directory.

Of course there are a ton of options, but I generally hate to browse through options unless I have to, so I'm happy with calling without argument.

Yesterday I was trying to rip a music video off a newly released DVD from Japan. I knew very little about how DRM (in this case, CSS) actually works and how to break it. I tried to operate directly on the VOB file with ffmpeg or mpv but both failed with a lot of header errors — I suppose more files than the VOB are required for authentication? Whatever, maybe I’ll learn the details in the future, but I don’t see the need since DVD is an outdated technology anyway.

So, can we proceed from here? Most certainly. I noticed that although mpv won’t let me play a single VOB, I can simply hand it the DVD mount point, and it will play the whole DVD seamlessly. Caution: mpv needs to be compiled with libdvdnav and libdvdread! With brew you just do

brew install mpv --with-libdvdnav --with-libdvdread

For better performance and backup, I first cloned the DVD into a .cdr image (DVD/CD-R Master Image) using Disk Utility (I've never tried creating/cloning image with diskutil CLI, so nothing to report on that). Then I mount the image, say the mount point is /Volumes/UPBX_80165. As said I can hand that mount point to mpv and it simply works, but how about extracting the MPEG-2 video stream? The --stream-capture=<filename> option is there just for you. In principle --stream-dump=<filename> should also work, but without monitoring the output and controlling where to end, I’m not sure if it will ever terminate itself when reading from a DVD (when I stream captured the DVD it just kept repeating itself until I explicitly quit with q). So that's it:

mpv --stream-capture=dump.mpg /Volumes/UPBX_80165

Then you can torture the dump.mpg with ffmpeg however you want. The most obvious thing is to cut out the music video part, and put into a new container like MPEG-TS. Or transcode it to H.264 for your iPhone. The nice thing about dump.mpg is that, unless I got it wrong, there's no quality loss here — the only thing you got rid of is that goddamn DRM.