more iMovie

Maybe the way to go is to just use iMovie/iDVD to create a DVD disk image, and then break it up into individual files by splitting up the .vob files at chapter boundaries, extracting MPEG-2 files from the DVD data that way. Then I'll only have had to encode each video once. Are there any tools to do that, for either OSX or Linux?

Meanwhile, I'm playing around with the "Export" settings in iMovie and trying to find a way to end up with an MPEG-4 file that is roughly equivalent to what iDVD is putting on the discs (in terms of size and quality) and I haven't found the right setting yet. I wonder what frame rate iDVD uses? Anything less than 30 (well, 24 and 15) has really visible field-splitting artifacts that don't show up in the DVD version; but those files are around 150% the size as they should be. (I think I should be ending up with roughly 53MB/minute, right? Because a DVD is 4.7GB, and iDVD writes 90 minutes max?) An export quality setting of "High" (75%?) seems ok, but "Medium" is crap. I'm using the default key frame rate of 90, and turned off data rate limit.

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18 Responses:

  1. waider says:

    World of Hurt: Enter here.

    I recently put together the bits required to play with DVDs and codecs on Linux. It's easy, you just install transcode.

    Of course, transcode needs a few libraries to support things like avi, dvd, and some mpeg variants.

    So you'll need avifile, and dvfile or dvlib or something, and mjpegtools.

    And they requires some libraries... you get the idea. Suffice to say that I spent more time assembling the parts to do the job than the system spent doing the transcoding.

  2. baconmonkey says:

    DVD uses essentially 30 fps (29.97 to be exact), however the data is interlaced to achieve an effective frame rate of 60 fps. interlaced video on computers tends to look awful as areas of rapid movement look like they've got combs sticking out of them. typically when people shoot video for computer use, they run a de-interlace filter and cut the resolution in half, ending up with 360x240 fideo files. but it gets more complicated as TVs and computers have different pixel aspect ratios. Tv is .909, which basically means a 704 pixel width video squeezed down to 640 looks right when the height remains unchanged at 480.

    I've seen people fit feature length movies ona single cd with mpeg 4 compression - without it looking too awful. Though I don't remember what resolution it was at.

    It took me a few reads of your vob paragraph to figure out what you were asking. Such tools do exist, for that's essentially what DeCSS is used for. or rather DeCSS massages the encrypted Vob files and makes them ready to be parsed by an vob to mpeg2 ripper.

    but a Vob has mpeg2 video and ac3 audio multiplexed. I dunno how your archives will play the ac3-audio. the extremely few guides for dvd extraction for mac all prety much center on converting to QT.

    I suppose you could demlutiplex (demux) the vob, convert the ac3 audio to mpeg1 layer II audio and re-multiplex it back into an mpeg file. or just try playing the vob file itself. though that won't do the chapter magic you want. There are a billion PC tools out there that do everything you want. like which handles chapters, languages, camera angles, etc from vob files.

    Though this might be somewhat helpful. I'm not sure though. there is a file on DVDs that explains what parts of which vob files have all the goods. I don't recall what it's called off hand. however, if you can figure out which one that is, and drag it onto the mac DVD player, you might be able to do something similar to what they're discussing above.

    This has a mac version of the demuxer.

    might find something here:

    • baconmonkey says:

      I think the MacMPEG2Decoder mentioned on this page might be able to attack the vobs directly.

      • baconmonkey says:

        I just gotta say, after digging around for about an hour looking for Mac guides/tools for this stuff, that I sure do appreciate my PC now. I believe I am now justified in knocking the teeth out of the next person who tries to explain that Macs are better for media.

        • jerronimo says:

          Macs are better for a good subset of the standard computer-using public who need to do either home-level common video editing and dvd authoring simply and easily (imovie/idvd) or the low end professional who needs to edit their independant digital film and possibly make dvds of it (Final Cut Pro/Avid/etc DVD Studio Pro). Anyone who needs to do more complex compressions / dvd authoring will already have a different way of doing it either on a PC, linux, or on their Avid console.

          But for the average, standard things that one might need to do, the bundled apps work well enough... and to be able to edit movies and author DVDs with zero learning curve is pretty impressive. Yes, you can't do some of the more complex things, Yes, iMovie doesn't deal well with anamorphic clips, and until recently, you couldn't do chapter stops, but to be able to let your grandmother make a reasonably nice DVD from her iMac is a pretty impressive task.

          The thing is that with the immense install base of the PC, you're gonna end up with a lot more tools, a lot more howtos for the PC than the Mac. Think about it... typically, the mac owner (until recently) was either in graphic/web design or an independant movie creator. Programmer types would stick to the PC since they were/are cheaper, and the software is less expensive generally. Being that the core of OS X is now a unix (bsd) and with the new machines coming down in price, you'll (very very slowly) start to see more people porting or writing free software for the mac, whcih brings over all of the linux software created. It's just not here yet.

          If you love the complexity of your pc, then keep with it... no one is asking you to switch.

          I personally love that on my mac, i can do 95% of the things I have to do without thinking about it, without the OS getting in the way, without the apps getting in the way. I'm not saying Mac/OS X is better than Windows. I'm saying it's better for me.

          you might also want to look on , btw.
          And as far as the mpeg2 stuff, just use Quicktime Pro, but you need to buy the mpeg2 codec from apple.

          • baconmonkey says:

            I'm surprised that with the ability to play a DVD, the mpeg2 codec isn't integrated into the OS. at least on PCs, once you install a DVD player program, you've got full mpeg2 access for playback. it's encoding that often requires a purchase, thanks to the lovely patents and royalties on tech used in mpeg2.

            but what Jamie is talking about here, is exracting the mpeg2 data that's already been encoded in the big ol' disk image thing that iDVD makes. though I suppose making DVD spec mpeg2 files intially from the DV files and pulling them into iDVD would take the same ammount of time. unles iDVD decides to re-encode everything to lock it into it's specs.

            • knowbuddy says:

              Actually, most commercial PC software DVD players (Sonic, PowerDVD) *don't* install standard codec DLLs or DirectShow filters (*.ax files). You can only play MPEG2 in their app, not in any media player. It sucks.

              (Yeah, you could probably figure out how to use their DLLs/OCXs to do the decoding/playback for you, but I'm talking out-of-the-box here.)

          • rpkrajewski says:

            Suppose I've got Quicktime Pro, and the MPEG-2 codec. Could you write a streamlined DVD production program with the Quicktime and Disc Recording APIs ?

            • jerronimo says:

              Actually, if you're writing your own app, you don't need to have quicktime pro installed.

              In fact, someone could come along and write their own version of quicktime pro, and give it away for free, and it would provide the same functionality. ... it's just that no one has done it yet.

              But yes... if you wanted to, you could.

              • rpkrajewski says:

                OK, so the only thing you need to have is firm grasp on how to lay out a Video DVD and access to the compressor for MPEG-2, which you have to pay for due to licensing issues.

                And a DVD burner. Unfortunately I don't have one of those...

                • jerronimo says:

                  if you write the software correctly, you don't need a burner... you could just create a dmg of the dvd, to be burned later.

                  And i believe there are a few tools for linux that help create the menu code.

          • jwz says:

            But for the average, standard things that one might need to do, the bundled apps work well enough...

            Well like, apparently not!

            I am shocked -- shocked and aghast -- that somehow I've gotten into "oh, what you're trying to do is hard territory already! All I'm trying to do is convert some old VHS tapes to DVD, and also have file-based copies of them that don't look like complete ass.

            Isn't that, like, the canonical use of iDVD?

            If it's not good for that, what precisely did they expect it to be used for?

            Just substitute "music videos" for "video of baby's first hit of crack" or something.

            • ronbar says:

              You can only fit a half-hour or so per disc, but SVCD is a pseudo-standard that just about everything plays and it mostly doesn't look like crap. MPEG4 seems to be years away from being well or widely implemented, and in the meantime on PCs there's divx.

              I hate `cutely'-named technology. divx is oh-so-ironic. And to rub salt in the wound, the official name is "divx :)".

  3. baconmonkey says:

    one more thing, then I'm done.

    Linux Video app. supposedly supports firewire capture and mpeg2. it *might* be able to save you some hassle by exporting mpeg2 files, which then idvd uses to make the big old disk image thing.

  4. jerronimo says:

    I've NEVER been able to find good settings for mpeg4 that haven't looked like ass.

    I'd load the captured video clips into Quicktime Pro (with the MPEG2 codec installed as well) then trim out the beginning and end of the clips, and save that new clip as both MPEG2 as well as .dv stream

    Then I would create a new project in iMovie, quit out of iMovie.
    Then drag the .dv clips into the Media folder in that newly created project folder, then start iMovie back up.
    (this eliminates the "import a clip" time.)
    iMovie will find the new clips. then just drag them to the timeline.

    Then just add chapter stops (if you're using iMovie 3), save out the project, load up iDVD and burn your disc.

  5. ioerror says:


    Google for it jwz.

    It's the solution.

    And it's easy to use.

    I ripped Einsturzende Neubauten in no time into segmented files.
    Encoded into various formats.


    Oh and it's in perl.

  6. omni_ferret says:

    If your output is MPEG-1 or MPEG-2, you might want to encode it in hardware anyway. This should cost under $200 new. Someone else already pointed out that DV is basically high-quality MJPEG, so converting involves recompression. Quicktime should allow lossless encoding, like huffyuv elsewhere.
    My second-hand impression (I discussed this with a friend) is that an MPEG-2-reading-and-writing Quicktime add-on is sold by Apple.
    MPEG-4 is unusual. I know open source encoders - such as FFmpeg (which can also do MPEG-2) and xvid - exist, even if I'm not sure they adhere to the MPEG-4 licensing strictly. divx avi files aren't quite MPEG-4; .avi files use keyindexes, while MPEG-4 is streamable, for example (I think). If you want to view MPEG-4 files, you can use Quicktime 6 or something like "Platform4 PC Player" (warning, flash, screwed up urls).
    If you really just want to split MPEG files, mpgtx can split and join MPEG-1 video, and splitting and joining MPEG-2 video is experimental. This wouldn't be pretty; it's a command-line program.