dvdauthor

DVD Background

At a high level, a DVD is a collection of menus and titles. Conceptually, a menu contains buttons which can be assigned actions and provides a list of choices to the end user, while a title contains the main content of the DVD. However, in reality many of the features available in menus (including buttons, pausing, and looping) are also available in titles.

The menus and titles are divided into titlesets and the VMGM menu set. A titleset can contain a number of menus and titles which are meant to act together. The "menu", "audio", "subtitle", and "angle" buttons on the DVD player's remote control will all access menus in the same titleset as the title which is being played. All the titles and menus of a given titleset have the same video, audio, and subtitle settings (the definitions for the menus are independent from the definitions for the titles), so if you want to have different settings (for example widescreen vs standard aspect ratios), then you need separate titlesets. Titlesets are not meant to jump to one another, so the VMGM menu domain is used. It is a collection of menus (no titles) that can access the menus and titles of all the titlesets.

One of the most frusterating things when deciding how to author a DVD is that there are often many ways to accomplish the same task. For example, you must decide whether to locate menus at the VMGM level or the titleset level. A typical setup is to locate the high level menus at the VMGM level, and the low level configuration menus (scene / audio / subtitle selection) at the titleset. If there are DVD extras, perhaps with a lower quality audio track and a 4:3 aspect ratio, then they would be in a separate titleset with a menu to select among the extras located at the titleset level.

dvdauthor Description

dvdauthor works in discrete operations. It authors each titleset one at a time, and then finally authors the VMGM to complete the disc. At that point the contents can be written out to a DVD. If you are controlling dvdauthor with command line arguments, then each step will occur independently; however if you are using the XML configuration file, then you have the option of combing some or all the steps into one.

The VOBs passed to dvdauthor must have DVD NAV (VOBU) packets multiplexed in at the correct locations. Many tools can do this, including mplex from mjpegtools 1.6.0 or later. dvdauthor will then fill these packets in with the correct data. Special care has been taken to ensure dvdauthor is fifo compliant; that is every source VOB can be the output of another program (such as mplex). This can make execution faster on many systems by avoiding extra filesystem accesses.

Command Line Description

XML Description

Here is the basic structure of the configuration file:

<dvdauthor [dest="output-dir"] [jumppad="1|on|yes"] >
   <vmgm>
      <menus [lang="language-code"] >
         <video [format="ntsc|pal"] [aspect="4:3|16:9"]
                [resolution="XxY"] [caption="field1|field2"]
                [widescreen="nopanscan|noletterbox"] />
         <audio [format="mp2|ac3|dts|pcm"] [channels="numchannels"]
                [quant="16bps|20bps|24bps|drc"] [dolby="surround"]
                [lang="language"] />
         [<audio ... />]
         <subpicture lang="language" />
         <pgc [entry="title"] [palette="yuvfile|rgbfile"]
              [pause="seconds|inf"]>
            <pre> commands; </pre>
            <vob file="file.mpg" [chapters="chapter-list"]
                 [pause="seconds|inf"] />
            [<vob ... />]
            <button [name="buttonname"]> commands; </button>
            [<button ... />]
            <post> commands; </post>
         </pgc>
         [<pgc ... />]
      </menus>
   </vmgm>
   <titleset>
      <menus>
         [<video ... />]
         [<audio ... />]
         <pgc [entry="root|subtitle|audio|angle|ptt"]
              [palette="yuvfile|rgbfile"] [pause="seconds|inf"]>
            [...]
         </pgc>
         [<pgc ... />]
      </menus>
      <titles>
         [<video ... />]
         [<audio ... />]
         <pgc [palette="yuvfile|rgbfile"] [pause="seconds|inf"]>
            [...]
         </pgc>
         [<pgc ... />]
      </titles>
   </titleset>
   [<titleset ... />]
</dvdauthor>

A breakdown of the config file:

Language Description

The language is quite simple and roughly looks like C.

• Statements are terminated with a semicolon.

• Statements can span multiple lines.

• Multiple statements can appear on one line.

• Whitespace (space, tab, newlines) are not important, except to separate keywords and identifiers.