dvd::rip documentation - Important concepts
Author: Joern Reder
Description: All about dvd::rip - the full featured DVD Ripper GUI for Linux, written in Perl - dvd::rip documentation - Important concepts
Keywords: dvd, rip, linux, perl, divx, transcode, video, mpeg, gtk, DVD, RIP, LINUX, PERL, DIVX, TRANSCODE, VIDEO, MPEG, GTK

# DOCUMENTATION | dvd::rip - Copyright © Jörn Reder, All Rights Reserved

# 5. Important concepts
This section introduces several underlying concepts you should know, at least the first few chapters are interesting for every dvd::rip user. Reading this section is surely optional, but may help understanding the reference sections later in this documentation. 5.1 A dvd::rip project 5.2 A DVD title 5.3 DVD ripping modes 5.4 Transcode modes 5.4.1 Standard mode 5.4.2 Cluster mode 5.5 Chapter mode 5.6 Multiple audio tracks 5.7 Video bitrate calculation 5.8 Splitting 5.9 Volume rescaling / Audio filters 5.10 Subtitle formats 5.11 PSU core 5.12 Video codecs 5.13 Audio codecs 5.14 Container formats 5.14.1 AVI 5.14.2 OGG 5.14.3 MPEG 5.15 Filesystem layout 5.16 dvd::rip info file
## 5.1 A dvd::rip project | [ Content ] [ Top ]
dvd::rip organizes its data in "projects". A project consists of all information regarding the rip of a specific DVD. This data is stored in a dvd::rip project file. This way you easily can pick up a rip at any time.
## 5.2 A DVD title | [ Content ] [ Top ]
A DVD consists of one or more titles. dvd::rip works strictly per title, that means your first decision when ripping a DVD is: which title do you want. All settings will be stored per title. Naturally you can rip more than one title from a DVD. But dvd::rip currently doesn't offer options to do things with many titles at once. But that's no relevant restriction, because titles usually differ so much, that applying the same parameters to different titles mostly makes no sense.
## 5.3 DVD ripping modes | [ Content ] [ Top ]
dvd::rip handles physicals DVD's and DVD images on harddisk as well. For both data source types you can choose between on-the-fly transcoding and VOB extraction before transcoding. It's always recommended to use VOB extraction, because dvd::rip offers more features in this mode. If you choose to use on-the-fly transcoding be aware of the following restrictions: You can't use the cluster mode You can't use the VOB movie preview function. You can't render subtitles on the movie. Grabbing preview frames is rather slow. Transcoding a frame range is rather slow. You can't use transcode's PSU core for optimizing NTSC A/V sync.
## 5.4 Transcode modes | [ Content ] [ Top ]
dvd::rip has two different modes for the expensive process of transcoding the movie: standard and cluster mode.
### 5.4.1 Standard mode
The standard mode can be used out of the box, no further configuration is necessary. The dvd::rip GUI will show a progress bar for the actual transcoding process. This way you can transcode one movie at one time. It's not possible to transcode several movies in parallel, in a row or some similar automated stuff. You can write simple batch scripts using dvd::rip's command line options for several projects, but the cluster mode provides a more comfortable batch facility.
### 5.4.2 Cluster mode
The cluster mode uses a different approach of transcoding movies. You can use all your Linux-aware hardware in your network to transcode the same movie. The movie is divided into several chunks, which can be transcoded in parallel by different machines. You can put as much projects as you like on the cluster. They will be processed in a row resp. in parallel, when possible. The power of the cluster mode is achieved with standard Unix components. Just dvd::rip, transcode, ssh and NFS/Samba/AFS or another network file system. Configuring is as easy as setting up a proper ssh and network file system communication.
## 5.5 Chapter mode | [ Content ] [ Top ]
Most DVD titles are divided into chapters. With dvd::rip's chapter mode you will have one file per chapter after transcoding. You can select all or individual chapters. Note, that you can't combine chapter and cluster mode. Note that vobsub creation (refer to subtitles) is disabled in chapter mode.
## 5.6 Multiple audio tracks | [ Content ] [ Top ]
Most DVD titles have multiple audio tracks, e.g. for different languages or directors comments. You can have multiple audio tracks also in the transcoded movies. This is supported for AVI, OGG and SVCD but not for VCD.
## 5.7 Video bitrate calculation | [ Content ] [ Top ]
The video bitrate is relevant for the video quality. The higher the better. But usually you want to fit the transcoded movie on a specific number of CD's. That's why the video bitrate is calculated, resp. derived from the space available (which is (desired target size) MINUS (size for audio tracks)).
## 5.8 Splitting | [ Content ] [ Top ]
When the target size is a multiple of a CD's size, dvd::rip can split the transcoded movie in pieces which fit on one CD. Each CD contains a valid movie file which can be played independently from the others.
## 5.9 Volume rescaling / Audio filters | [ Content ] [ Top ]
The DVD sound often is too low, so you want to increase the volume. You can use transcode's volume rescaler for this. First the audio track is scanned for the maximum volume. With this scan value transcode raises the volume to the maximum possible while transcoding. Volume rescaling is very static, you may find the sound is still too low, if your movie's sound is very dynamic. transcode offers some audio filters, which adjust the volume dynamically, which you can choose also in dvd::rip.
## 5.10 Subtitle formats | [ Content ] [ Top ]
There are several possibilities to rip subtitles: Rendering on the movie Creating vobsub files Creating text files dvd::rip supports the first two. transcode can render one subtitle straight on the movie. The disadvantage: the subtitles aren't optional anymore, you can't switch them off. Also it's not possible to have more than one subtitle with your movie. With vobsub files switching off is still possible. A vobsub file mainly contains the original DVD subtitle stream. A vobsub capable movie player (e.g. mplayer) can read vobsub files and renders the subtitles on-thy-fly. You can have more than one stream in a vobsub file. The quality is the same as of the original DVD. So having subtitles in vobsub files is really a good choice. Text subtitles are somewhat similar to vobsub, but the format is ASCII. The subtitle images are extracted and then converted to text using an OCR software. This way the subtitles need less space, but the OCR part isn't very stable - often you have to correct the generated text files manually. dvd::rip doesn't support this. You have to use subtitleripper manually if you want to have text subtitles.
## 5.11 PSU core | [ Content ] [ Top ]
The PSU core is a transcode mode, which applies a special handling for movies consisting of several PSU's. PSU stands for Program Stream Unit, and is a DVD internal concept of dividing the video stream into independent parts. With NTSC sources (and also some PAL movies) these PSU's may cause serious A/V synchronization issues, which the PSU core mode tries to solve (for NTSC movies dvd::rip switches PSU core by default on). This works for most movies. If you can't get proper A/V sync with your movie (even with PSU core enabled), please contact the transcode developers and provide sample material. dvd::rip enables the PSU core by default for NTSC titles, which have more than one PSU. You can't use the cluster mode or fast frame range transcoding with it.
## 5.12 Video codecs | [ Content ] [ Top ]
The video codec defines the format of the resulting video stream. dvd::rip supports mostly all transcode video codecs, e.g.: Xvid, ffmpeg4, DivX 4/5, mjpeg and others. Xvid support is divided into two versions: the latest stable release and current CVS. dvd::rip also offers (S)VCD support with transcode's mjpeg export filter, the bbmpeg filter isn't supported yet.
## 5.13 Audio codecs | [ Content ] [ Top ]
DVD audio streams are usually encoded using the AC3 format. You can passthrough the AC3, so no re-encoding is necessary, which gives best audio quality. Also you keep 5.1 surround sound (if it's 5.1 AC3). But AC3 streams need considerably more space than MP3 or Vorbis streams, so if you don't need the 5.1 format you should re-encode the audio to one of these. dvd::rip supports both MP3 and Vorbis. The (S)VCD specification defines MP2 as the audio format, so you have no choice here.
## 5.14 Container formats | [ Content ] [ Top ]
The container is the file structure which multiplexes all streams, video and audio, into one file, which can be played by a movie player. There are currently three container formats supported by dvd::rip:
### 5.14.1 AVI
The AVI format is used for all video codecs but MPEG (e.g. Xvid/DivX/ffmpeg4). You can only have MP3 and AC3 audio codecs with the AVI container, no Vorbis.
### 5.14.2 OGG
The OGG container supports the same video codecs as AVI, including MP3 and AC3, and additionally Vorbis.
### 5.14.3 MPEG
The MPEG container only supports the MPEG1/2 video codecs and MP2 audio. Usually you create (S)VCD or CVD images from MPEG files (dvd::rip can do this for you with its CD burning module).
## 5.15 Filesystem layout | [ Content ] [ Top ]
dvd::rip collects all files regarding a project in the directory you specify when starting a new project. The layout of this directory is as follows:
      vob/                          Directory for ripped VOB files
      vob/001/                      VOB files of DVD title #1
      vob/001-C001/                 VOB files of DVD title #1, chapter #1

      avi/                          Directory for transcoded files
      avi/001/foo-001.{avi,ogg,mpg} transcoded files of DVD title #1
      avi/001/foo-001.dvdrip-info   dvd::rip info file of DVD title #1

      avi/001/foo-001-01.vobsub     vobsub file of DVD title #1, Subtitle #1
      avi/001/foo-001-01.idx        vobsub idx file of DVD title #1, Subtitle #1
      avi/001/foo-001-01.ifo        vobsub ifo file of DVD title #1, Subtitle #1
      avi/001/foo-001-01.rar        vobsub rar file of DVD title #1, Subtitle #1

      avi/001/foo-001.iso           ISO 9660 image of DVD title #1
      avi/001/foo-001.vcd           VCD image of DVD title #1
      avi/001/foo-001.svcd          SVCD image of DVD title #1

      tmp/                          Directory for temporary files
      tmp/backup.rip                Backup project file (written after TOC reading)
      tmp/*.jpg                     Preview images of all DVD titles
      tmp/logfile.txt               Logfile
      tmp/foo-001-nav.log           VOB navigation file of DVD title #1
In case of multi-cd rips some of the transcoded files (and CD images) appear multiple times. The CD number is appended to the filename (e.g. foo-001-00001.ogg, foo-001-00002.ogg etc.)
## 5.16 dvd::rip info file | [ Content ] [ Top ]
A *.dvdrip-info file will be created when you transcode a movie. It's a simple text file which contains all interesting technical information about your rip (e.g. bitrates, audio tracks, codecs etc.). This way you later know which settings applied to this specific rip. A .dvdrip-info file looks like this:
    # Movie information file. Generated by dvd::rip; http://www.exit1.org/dvdrip

    [General]
    Title:                 tubular_bells
    Data source:           DVD
    DVD title number:      1
    Runtime:               01:04:38

    [Video]
    Video format:          PAL
    FPS:                   25
    Size:                  624 x 464
    Video bitrate (kbps):  2893
    Video codec:           xvid
    2-pass-encoded:        yes
    Fast resizing:         yes
    Deinterlacer filter:   Zoom to full frame (slow)
    Antialiasing filter:   No antialiasing

    [Audio 1]
    DVD audio track id:    1
    Language:              en
    Audio codec:           ac3
    Channels:              6
    Sample rate:           48000
    Audio bitrate (kbps):  448
    Volume rescaling:      none
    Audio filter:          None, volume rescale only

    [Programs]
    dvd::rip version:      0.47_10
    transcode version:     0.6.2.20021010

DOCUMENTATION | dvd::rip - Copyright © Jörn Reder, All Rights Reserved