vobcopy, dvdbackup, etc.

A few days ago, I was cloning my entire Audio CD and DVD collection, and reported some of the findings in this post. As said, the most important commands are

hdiutil makehybrid -iso -joliet -o AUDIO_CD_NAME.iso SOURCE

for Audio CDs and

hdiutil makehybrid -udf -o DVD_NAME.iso SOURCE

for DVDs.

Those alone don't finish the story. I also tried other things and unfortunately encountered problems. I was too busy to report back then, but now I'll summarize some of the findings.

For one thing, hdiutil makehybrid might fail, issuing an "Operation not permitted" for no obvious reason. This could even happen when you work with the Disk Utility GUI (for which I once got a "Permission denied"). Even sudo didn't help in my case. However, I was able to circumvent the problem with the root shell (I won't tell you how to enter the root shell — you need to at least have that amount of knowledge about the root shell before you are given the key). Not sure why. Just keep in mind that the root shell might help (that's also a general, albeit dangerous, advice for life).

Next onto grabbing the raw VOB.

vobcopy is pretty sweet, but at least for me it had one huge problem. When I tried to copy a single title, say title #2 with

vobcopy --title-number TITLE_NUMBER -i SOURCE

other titles got copied, too. I didn't have enough samples to test out, but presumably it's because the problematic DVD has a structure like this:

problematic DVD title structure

Anyway, no matter I vobcopy title 01, 02, or 03, the result was the same — the whole thing. That's pretty stupid. I don't know if it counts as a bug or unfinished feature. Definitely not cool.

(One cool thing about vobcopy: as long as you complied with libdvdread, you can create a fully decrypted version of the DVD with

vobcopy --mirror -i SOURCE

Of course, to get an iso image out of the decrypted mirror, you run the hdiutil makehybrid -udf command given above.)

So vobcopy is dead (for copying specific titles in unfortunate DVDs). What's next?

There's dvdbackup. The man page is good, and ArchWiki is even better (ArchWiki is awesome!), providing you cookbook solutions of combining the power of dvdbackup and dvdauthor (cookbooks are nice when dealing with unexciting technologies like DVD). In fact, dvdbackup alone is enough for extracting the VOBs of relatively small titles (< 1GiB):

dvdbackup -i SOURCE -o VOB_TARGET_DIR -t TITLE_NUMBER -n TITLE_NAME

then grab your title-specific VOB in VOB_TARGET_DIR/TITLE_NAME/VIDEO_TS. Unlike vobcopy's -n/--title-number option, dvdbackup's -t/--title option does it right, trimming everything else. However, there's a problem when the title is larger than 1 GiB — then dvdbackup will split the VOB into several 1 GiB max pieces, and there's no way to disable this (since dvdbackup is targeting a DVD player — ancient technology — rather than mpv or whatever). What's sadder is that I can't seem to combine the split VOBs with FFmpeg stream copy — pcm_dvd audio always gets converted to mp2 and fails when I use -c copy. I'm not a codec expert, but I suppose this is due to the fact that pcm_dvd isn't a supported encoding codec of FFmpeg (at least not my FFmpeg):

> ffmpeg -codecs | grep pcm_dvd
D.A..S pcm_dvd              PCM signed 20|24-bit big-endian

D is for "Decoding supported", A is for "Audio codec", S is for "Lossless compression" — no encoding support. By the way, my FFmpeg is brewed with the options --with-fdk-aac, --with-ffplay, --with-freetype, --with-libass, --with-libbluray, --with-openjpeg, --with-openssl, --with-x265:

> \ffmpeg -version
ffmpeg version 2.4.2 Copyright (c) 2000-2014 the FFmpeg developers
built on Oct 19 2014 14:09:36 with Apple LLVM version 6.0 (clang-600.0.51) (based on LLVM 3.5svn)
configuration: --prefix=/usr/local/Cellar/ffmpeg/2.4.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid --enable-libfreetype --enable-libass --enable-ffplay --enable-libfdk-aac --enable-openssl --enable-libx265 --enable-libopenjpeg --disable-decoder=jpeg2000 --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.1_1/include/openjpeg-1.5 '
libavutil      54.  7.100 / 54.  7.100
libavcodec     56.  1.100 / 56.  1.100
libavformat    56.  4.101 / 56.  4.101
libavdevice    56.  0.100 / 56.  0.100
libavfilter     5.  1.100 /  5.  1.100
libavresample   2.  1.  0 /  2.  1.  0
libswscale      3.  0.100 /  3.  0.100
libswresample   1.  1.100 /  1.  1.100
libpostproc    53.  0.100 / 53.  0.100

Maybe I missed some --enable.

Sorry for the digression. So, it's not possible to stream-copy-concat the VOBs with FFmpeg. (In fact, since audio quality is not that important — you won't be able to tell 256k AAC from lossless anyway, especially when you are focusing on the video, so you can always transcode pcm_dvd into 256k AAC with -c:a libfdk_aac -b:a 256k. mpeg2video is an encoding supported codec so stream copy works fine. Or you may also use flac or whatever encoding-supported lossless codec.) However, if you insist on getting the original pcm_dvd, there is a way, an ugly way. You've gotta be creative here. ArchWiki already provides a cookbook solution on how to use dvdbackup and dvdauthor to create a DVD with a selected title. And vobcopy can copy the entire thing just fine, without the 1 GiB limit (make sure to use the -l/--large-file option if the size is greater than 2 GiB). Therefore, you can create a DVD with selected title from the original DVD, then vobcopy from the new DVD. This is insane, but it works, I've tested that. Note, however, that timestamps might be wrong with vobcopy, so the VOB runs just fine linearly but might run into problems when you seek. Therefore, FFmpeg is still the way to go. Or maybe you can do it right with one click using some closed source software ☹ — I've heard about success stories with the long ceased DVD Decrypter Windows project. In reality, I guess only people with theoretical interest or OCD will ever do this — FLAC or AAC should serve everyone just fine. It should have worked with vobcopy alone, but it doesn't. Hence the workaround.

For future reference, I'll translate the ArchWiki cookbook solution here (it's too cookbook itself, specifying paths like ~/movie_name and using unnecessary cd) about creating a title-specific DVD from a multi-title DVD (replace SOURCE, VOB_TARGET_DIR, DVD_TARGET_DIR, TITLE_NUMBER, and TITLE_NAME with sane values):

dvdbackup -i SOURCE -o VOB_TARGET_DIR -t TITLE_NUMBER -n TITLE_NAME
dvdauthor -t -o DVD_TARGET_DIR VOB_TARGET_DIR/TITLE_NAME/VIDEO_TS/*.VOB
export VIDEO_FORMAT=NTSC
cd DVD_TARGET_DIR/VIDEO_TS && dvdauthor -T -o DVD_TARGET_DIR

export VIDEO_FORMAT=NTSC is to avoid the dvdauthor error of "no default video format, must explicitly specify NTSC or PAL" (I'm not sure about the difference between NTSC and PAL, but I saw NTSC printed on my DVD, so I used it). And there you go, a shiny new DVD filesystem located in DVD_TARGET_DIR. (Note that unlike vobcopy, dvdbackup doesn't feature a nice progress bar even when -v/--verbose and -p/--progress are specified.) Then you can

vobcopy -l DVD_TARGET_DIR

if you'd like to. Recall that timestamps might be wrong, sadly.