DVD-Video
DVD-Video is a consumer video format used to store digital video on DVD (DVD-ROM) discs, and is currently the dominant consumer video format in Canada, Europe and Australia. Discs using the DVD-Video specification require a DVD drive and an MPEG-2 decoder (e.g., a DVD player, or a DVD computer drive with a software DVD player). Commercial DVD movies are encoded using a combination of MPEG-2 compressed video and audio of varying formats (often multi-channel formats as described below). Typical data rates for DVD movies range from 3–10 Mbit/s, and the bit rate is usually adaptive.
Resolution and Frame rate
DVD-Video can consist of either MPEG-2 at up to 9.8 Mbit/s (9800 kbit/s) or MPEG-1 at up to 1.856 Mbit/s (1856 kbit/s).
The following formats are allowed for MPEG-2 video:
- At 25 fps (usually used in regions where PAL is standard):
720 × 576 pixels MPEG-2 (Called full D1)
704 × 576 pixels MPEG-2
352 × 576 pixels MPEG-2 (Called Half-D1, same as the China Video Disc standard)
352 × 288 pixels MPEG-2
- At 29.97 or 23.976 fps (usually used in regions where NTSC is standard):
720 × 480 pixels MPEG-2 (Called full D1)
704 × 480 pixels MPEG-2
352 × 480 pixels MPEG-2 (Called Half-D1, same as the China Video Disc standard)
352 × 240 pixels MPEG-2
The following formats are allowed for MPEG-1 video:
- 352 × 288 pixels MPEG-1 at 25 fps (Same as the VCD Standard)
- 352 × 240 pixels MPEG-1 at 29.97 fps (Same as the VCD Standard)
Other requirements
Interlacing is only supported for MPEG-2 video, due to MPEG-1 constraints. 16:9 aspect ratio anamorphic video is only supported at 720 × 576/480, and all resolutions support 4:3 aspect ratio video. The maximum chapters allowed per title is 99 and the maximum titles allowed per DVD is 99.
DVD-Video discs have a raw bitrate of 11.08 Mbit/s, with a 1.0 Mbit/s overhead, leaving a payload bitrate of 10.08 Mbit/s. Of this, up to 3.36 megabits can be used for subtitles and a maximum of 9.80 megabits can be split amongst audio and video. In the case of multiple angles the data is stored interleaved, and so there's a bitrate penalty leading to a max bitrate of 8Mbit/s per angle to compensate for additional seek time. This limit is not cumulative, so each additional angle can still have up to 8Mbit/s of bitrate available.
Professionally encoded videos average a bitrate of 4.0-5.0 Mbit/s with a maximum of 7–8 Mbit/s in high-action scenes. This is typically done to allow greater compatibility amongst players, and to help prevent buffer underruns in the case of dirty or scratched discs.
Columbia TriStar Home Entertainment has created a line of DVDs (dubbed "Superbit") aiming to maximize picture quality by eliminating multiple languages, angles, and audio tracks. This allows average bitrates closer to 6 Mbit/s.
Some DVD hardware or software players may play discs whose MPEG files do not conform to the above standards; commonly this is used to support DVD discs authored with formats such as VCD and SVCD. While VCD and CVD video is supported by the DVD standard, neither SVCD video nor VCD, CVD, or SVCD audio is compatible with the DVD standard.
Some hardware players will also play DVD-ROMs or CD-ROMs containing "raw" .mpg MPEG video files; these are "unauthored" and lack the file and header structure that defines DVD-Video. Standard DVD-Video files contain extra information (such as the number of video tracks, chapters and links to extra features) that DVD players use to navigate the disc.