Super video compact disc
A Super Video CD (SVCD) is a disc format of consumer electronics and computer technology to store movies and videos in digital , compressed form. A conventional compact disc (CD) serves as the data carrier .
description
The SVCD differs from the original Video CD format (VCD) primarily in terms of improved image quality and a shorter running time. This requires the playback devices (SVCD-compatible DVD players or portable SVCD players) to have faster drives and higher computing power. The picture quality is somewhat lower than with DVD-Video , and the sound quality does not quite reach the quality of a DVD . Digital surround sound is officially supported ( MPEG-2 Audio Multichannel 5.1 or 7.1), but there are only a few players that can play it. Two different audio tracks on a single disc are allowed, but just as with multi-channel audio, you have to accept severe losses in image quality and runtime.
In this format, around 35 to 55 minutes of film or television material is usually compressed in such a way that it can be stored on a standard 700 MB compact disc - therefore several SVCDs are usually required for one feature film. The more minutes you save per disc, the worse the picture quality will be. It is entirely possible to save 90 minutes on an SVCD with a minimum sound and image data rate - but the image and sound quality will then be below VHS level. A non-standardized variant of the video CD, which is largely compatible with the SVCD, is the MVCD , which achieves high SVCD picture quality with a playing time of up to 120 minutes and is played by almost all DVD players. It also contains an MPEG-2 program stream with variable bit rates and an MP3 audio track.
Like the VCD format, the SVCD is standardized. While the VCD standard is recorded in the "White Book", the SVCD is outside the "Colorful Books" of the official CD formats and for a long time - in contrast to the VCD - was also not allowed to use the "Compact Disc" only awarded by Philips - Wear logo. In the meantime, the CD consortium has also awarded a “Compact Disc” logo for SVCD - the signature is “Super Video”.
The format was not very successful commercially, except in the People's Republic of China , where it was developed. Nevertheless, films are still sold commercially on SVCD in small quantities. The format was originally intended to be replaced by the introduction of the DVD standard. Due to the possibility of storing films (especially commercial ones) on cheap, writable CD-Rs , the format experienced a renaissance as a medium for self-burned DVD copies, especially during the years when DVD-R Burners and media were much more expensive than CD-R.
In order to copy the content of a DVD onto SVCDs, the DVD image format ( MPEG-2 ) is converted into SVCD (also MPEG-2, but with a lower resolution and data rate) by means of very complex calculations , the audio format is (mostly) Transcoded from Dolby Digital 5.1 at 48 kHz to MPEG1 (Layer 2) -encoded stereo or Dolby Surround at 44.1 kHz. Most DVD players today support SVCDs.
specification
- Television standard PAL / SECAM -B / G / D / K / I / N: 480 × 576 pixels, 25 frames per second
- Television standard NTSC -M (or PAL -M): 480 × 480 pixels, 29.97 or 23.976 frames per second
- Aspect ratio 4: 3 or 16: 9
- Still images up to 720 × 480 or 720 × 576
- Image coding in ( MPEG-2 ) with variable (Variable Bit Rate, VBR) or constant (Constant Bit Rate, CBR) data rate , progressive or interlaced (480p / 576p or 480i / 576i).
- One or two sound tracks with 44.1 kHz in mono, ( joint ) stereo or multi-channel 5.1 / 7.1, data rate mostly between 128 and 224 kbit / s
- According to the standard, the total data rate (audio stream (s) and video stream) may not exceed 2778 kbit / s.
- Up to four selectable subtitles can be displayed, but many (allegedly) compatible DVD players do not support this, so that subtitles are often firmly integrated into the picture, as is the case with the VCD.
When encoding videos in SVCD-compatible video streams, particular attention should be paid to the aspect ratio so that the image is not squashed or too small.
SVCD modifications
Further, not officially standardized and almost only used for copies modifications of VCD and SVCD are among others. a. AVCD, MVCD , XVCD , TVCD , KVCD , RSVCD , TSVCD , MSVCD, KSVCD and XSVCD .