DcVD
DcVD (Dreamcast Video Disc) is the proprietary video format based on the MPEG SOFDEC exclusively for the Sega Dreamcast. It includes custom encoded video in Sofdec (.sfd) format as well as the mpeg sofdec program on a CD prepared for self-boot. Similar to standards set for DVD video, VCD etc., DcVD is an attempt to establish a video standard on the Sega Dreamcast Game Console.
At maximum bitrates, it is possible to fit approximately. 38 minutes of near DVD quality video at true 480p EDTV on one CD. (For true progressive scan, the DC VGA adapter is required.)
Compression Dreamcast Video Disc [ CDcVD ]
Using lower overall bitrates combined with the "Notch" Quantize Matrix allows up to 2 hours of near DcVD quality video on one 80 minute CD.
Video Specifications
"OVERRiDE" has released a new SFD player for Dreamcast, "SFDC Player R11b", allowing a maximum video resolution of up to 704x480p. Video Specifications are now updated for this new player.
Format: Mpeg-1 (.m1v)
FrameRate: 23.976frame/s, 24frame/s, 25frame/s, 29.976frame/s, 30frame/s, 60frame/s (Match Source FrameRate)
DcVD Resolution:
- 704x480p (4:3, Widescreen material letterboxed)
- 512x384p (4:3, only for Fullscreen material)
- SFDC Player R11b will stretch any resolution up to 704x480 before output. Therefore, widescreen material must be letterboxed. Any resolution in multiples of 32x16 are supported.
kDcVD Resolution:
- 512x384p (4:3, Widescreen material letterboxed, recommended for up to 90min/CD)
- 352x288p (4:3, Widescreen material letterboxed, recommended for up to 120min/CD)
- 352x240p (4:3, only for Fullscreen material)
DcVD Bitrate:
- Variable Bitrate (VBR)
- Minimum Bitrate: 448 kbit/s
- Maximum Bitrate: 3,200 kbit/s ( 3.2 Mbit/s )
- Average Bitrate: 2,200 kbit/s ( 2.2 Mbit/s )
kDcVD Bitrate:
- Variable Bitrate (VBR)
- Minimum Bitrate: 64 kbit/s
- Maximum Bitrate: 3,200 kbit/s ( 3.2 Mbit/s )
- Average Bitrate: 656 kbit/s ( approx. 120 minutes / CD ) through 952 kbit/s ( approx. 90 minutes / CD )
Video Buffer Size (VBV): 212kb
GOP Structure: I P pictures only for better cpu usage, or Default for better quality
DcVD Quantize Matrix: "Notch" quantize matrix ( copyright Karl Wagner )
kDcVD Quantize Matrix: "Notch" quantize matrix ( copyright Karl Wagner )
Audio Specifications
DcVD: Linear PCM at DVD Quality (.wav) compressed into Sofdec Audio 44 kHz 396 kbit/s ( .sfa CD Quality )
kDcVD: Linear PCM at CD Quality (.wav) compressed into Sofdec Audio 32 kHz 144 kbit/s ( .sfa TV Quality )
[.m1v and .sfa must be multiplexed into .sfd Sofdec data (not explained here).]
Other Applications
Dreamcast-encoded sofdec video is the most common video format used for the console, and is commonly "downsampled" to fit a back-up of a GD-Rom onto a CD-R.
For example, it is standard to see sofdec video with a resolution of 320x240 and a bitrate of 3600kbit/s on Dreamcast. It is possible to use a much lower bitrate ( i.e. 800kbit/s ) with no noticeable difference using the video compression techniques explained here.
See also
External links
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