This is pretty much a for your information type of post. As the title suggests, it's to do with release types. I'll rank them more or less according to the quality you can expect out of these releases with the best being put on top. Of course, this isn't absolute, but it gives you a general idea as far as quality goes.
BD/BRRip
Labels/Tags: BDRip, BRRip, Blu-Ray, BluRay, BLURAY, BDR, BD5, BD9, BD25, BD50
Description: The source for this release is a Blu-ray Disc. A BD/BRRip in DVD-Rip size often looks better than a same-size DVD rip because encoders have better source material. A common misconception among downloaders is that BDRip and BRRip are the same thing. They differ in that a BDRip comes directly from the Blu-ray source, while a BRRip is encoded from a pre-release, usually from a 1080p BDRip from another group. BDRips are available in DVD-Rip sized releases (commonly 700 MB and 1.4 GB) encoded in Xvid or x264, as well as larger DVD5 or DVD9 (often 4.5 GB or larger, depending on length and quality) sized releases encoded in x264.
BD5 or BD9 are slightly smaller than their counterpart DVD5/DVD9 releases. More recent types of BD5 and BD9 are commonly referred to as BD25 or BD50.
BD/BRRips come in various versions: the m-720p (or mini 720p), which is a compressed version of a 720p and usually weighs around 2–3 GB; the 720p, which usually weighs around 4–7 GB and is the most downloaded form of BDRip; the m-1080p (or mini 1080p), which usually weighs a little bit more than 720p; and the 1080p, which can weigh from 8 GB to sizes as big as 40–60 GB. There are also mHD (or mini HD) versions available, which are encoded in lower resolution and are smaller in size.
WEB-DL
Labels/Tags: WEBDL, WEB DL, WEB-DL
Description: This is a movie or TV show downloaded via an on-line distribution website (web download) like Amazon or iTunes. The quality is quite good since they are not re-encoded. The video (H264) and audio (AC3/AAC) streams are usually extracted from the iTunes or Amazon file and then remuxed into a MKV container without sacrificing quality. Most of these releases have no network logos on screen, just like BD/DVDRips.
DVD-R
Labels/Tags: DVDR, DVD-Full, Full-Rip, ISO rip, lossless rip, untouched rip, DVD-5/DVD-9
Description: A final retail version of a film in DVD format, generally a complete copy from the original DVD. If the original DVD is released in the DVD-9 format, however, extras might be removed and/or the video re-encoded to make the image fit the less expensive for burning and quicker to download DVD-5 format. DVD-R releases often accompany DVD-Rips. DVD-R rips are larger in size, generally filling up the 4.37 or 7.95 GiB provided by DVD-5 and DVD-9 respectively. Untouched or lossless rips in the strictest sense are 1:1 rips of the source, with nothing removed or changed, though often the definition is lightened to include DVDs which have not been transcoded, and no features were removed from the user's perspective, removing only restrictions and possible nuisances such as copyright warnings and movie previews.
DVD-Rip
Labels/Tags: DVD-Rip
Description: A final retail version of a film, typically released before it is available outside its originating region. The release is an AVI file and uses the Xvid codec (earlier DivX) for video, and mp3 or AC3 for audio. Because of their high quality, DVD-Rips generally replace any earlier copies that may already have been circulating. Widescreen DVDs used to be indicated as WS.DVDRip.
WEB Rip
Labels/Tags: WEB-Rip, WEBRIP, WEB Rip
Description: This is a rip created by capturing video from a screen, either broadcast or using a service like Hulu or Netflix. Quality can range from mediocre (comparable with low quality XVID encodes) to excellent (comparable with high quality BR encodes). Essentially, the quality of the image obtained depends on internet connection speed and the specifications of the recording machine.
HDTV or DS Rip
Labels/Tags: DSR, DSRip, DTHRip, DVBRip, HDTV, PDTV, TVRip, HDTVRip
Description: TVRip is a capture source from an analog capture card (coaxial/composite/s-video connection). Digital satellite rip (DSR) is a rip that is captured from a non standard definition digital source like satellite. HDTV or PDTV or DTH (Direct To Home) rips often come from Over-the-Air transmissions. With an HDTV source, the quality can sometimes even surpass DVD.
Analog, DSR, and PDTV sources are often re-encoded to 512×384 if fullscreen, 640×352 if widescreen. HDTV sources are re-encoded to multiple resolutions such as 640×352 (360p), 960×528 (540p), and 1280×720 (720p) at various file sizes for pirated releases. They can sometimes be progressive scan captured (480i digital transmission).
R5
Labels/Tags: R5, R5.LINE, R5.AC3.5.1.HQ
Description: The R5 is a retail DVD from region 5. Region 5 consists of the Indian subcontinent, most of Africa, North Korea, Russia and Mongolia. R5 releases differ from normal releases in that they are a direct Telecine transfer of the film without any of the image processing. If the DVD does not contain an English-language audio track, the R5 video is synced to a previously released English audio track. Then a LiNE tag is added. This means that the sound often is not as good as DVD-Rips. To account for the lesser audio quality typically present in R5 releases, some release groups take the high quality Russian or Ukrainian 5.1 channel audio track included with the R5 DVD and modify it with audio editing software. They remove the non-English spoken portion of the audio and sync the remaining portion, which contains high quality sound effects and music with a previously recorded source of English vocals usually taken from a LiNE tagged release. The result of this process is an almost retail DVD quality surround sound audio track which is included in the movie release. Releases of this type are normally tagged AC3.5.1.HQ and details about what was done to the audio track as well as the video are present in the release notes.
Screener
Labels/Tags: SCR, SCREENER, DVDSCR, DVDSCREENER, BDSCR
Description: These are early DVD or BD releases of the theatrical version of a film, typically sent to movie reviewers, Academy members, and executives for review purposes. A screener normally has a message overlaid on its picture, with wording similar to: "The film you are watching is a promotional copy. If you purchased this film at a retail store please, contact x-xxx-xx-xxxxxx to report it." Some movie studios also release their screeners with a number of scenes of varying duration shown in black-and-white. some movie studios release their screeners with a number of scenes of varying duration shown in black-and-white.
Since the content may differ from a retail version, it can be considered as lower quality than a DVD-Rip (even if the screener in question was sourced from a DVD).
Telecine
Labels/Tags: TC, TELECINE
Description: A copy captured from a film print using a machine that transfers the movie from its analog reel to digital format. Telecine has basically the same quality as DVD, since the technique is same as digitizing the actual film to DVD. However, the result is inferior since the source material is usually a lower quality copy reel. Telecine machines usually cause a slight left-right jitter in the picture and have inferior color levels compared to DVD.
VODRip
Labels/Tags: VODRip, VODR
Description: VODRip stands for Video-On-Demand Rip. This can be done by recording or capturing a video/movie from an On-Demand service such as through a cable or satellite TV service. Most services will state that ripping or capturing films is a breach of their use policy, but it is becoming more and more popular as it requires little technology or setup. There are many online On-Demand services that would not require one to connect their TV and computer. It can be done by using software to identify the video source address and downloading it as a video file which is often the method that bears the best quality end result. However, some people have used screen cams which effectively record, like a video camera, what is on a certain part of the computer screen, but does so internally, making the quality not of HD quality, but nevertheless significantly better than a Cam or Telesync version filmed from a cinema, TV or computer screen.
The quality can vary immensely (ranging from near DVD like to near Cam like) based on the equipment and source used by the On-Demand service.
Telesync
Labels/Tags: TS, TELESYNC
Description: A telesync (TS) is a bootleg recording of a film recorded in a movie theater, sometimes filmed using a professional camera on a tripod in the projection booth. The main difference between a CAM and TS copy is that the audio of a TS is captured with a direct connection to the sound source (often an FM microbroadcast provided for the hearing-impaired, or from a drive-in theater). Often, a cam is mislabeled as a telesync.
PDVD
Labels/Tags: PDVD, Pre-DVD
Description: This is a release type found mostly in India and/or for Indian movies, with Hollywood movies being the majority. Low quality CAM/TS releases in India are put on DVD and sold on the streets, which are then ripped by some release groups and released as PDVD-rips. They are often mistaken for being DVD-rips, due to the name.
Cam
Labels/Tags: CAMRip, CAM
Description: A copy made in a cinema using a camcorder or mobile phone. The sound source is the camera microphone. Cam rips can quickly appear online after the first preview or premiere of the film. The quality ranges from terrible to mediocre, depending on the group of persons performing the recording and the resolution of the camera used. The main disadvantage of this is the sound quality. The microphone does not only record the sound from the movie, but also the background sound in the cinema. The camera can also record movements and audio of the audience in the theater, for instance, when someone stands up in front of the screen, or when the audience laughs at a funny moment in the movie.
Note: Collected largely from Wiki.