XVCD
The XVCD (eXtended Video CD) is a non-standard video CD (VCD) for storing video data on a normal CD-ROM or CD-R (W), which offers a longer playback time.
A normal VCD is coded using the MPEG-1 method with constant bit rate (CBR), ie all scenes are coded with the standard 1150 kbit / s for the video stream; regardless of whether it is a fast, moving scene or a largely static still image.
The eXtended-VCD is MPEG-1 coded, with variable bit rate (VBR), i. H. The bit rate is increased to around 2000 kbit / s for fast scenes, but can drop to up to 300 kbit / s for very quiet scenes. A modified quantization matrix is also used and - in order to gain more storage space - the bit rate of the audio track is reduced and, if necessary, the GOP (Group of Pictures) is extended.
With these changes, a feature film of around 2 hours can be put on a single CD.
In addition to VCD, there are other versions for resolutions from 352 × 288 up to 720 × 576 pixels and in the television standards PAL and NTSC, which can be found under the heading "eXtended". Colloquially, XVCD for MPEG1, VCD resolution and 1-CD file size for a video file has prevailed.
By closely following the SVCD standard (here "variable bit rate") , most DVD players can play XVCDs in VCD resolution (352 × 288 PAL or 352 × 240 NTSC). Experience has shown that especially “cheap players” in the lower (consumer) price range have fewer (!) Problems here. Historically, this extension of the format originates from the Asian region in order to be able to save complete feature films on CD free of license fees and to be able to play them on the simplest video players.
XVCD variants (XVCD, MVCD, KVCD, AVCD ...) differ essentially in terms of resolution, bit rate, GOP and the quantization matrix used. If necessary, attention should be paid to possible compatibility problems, for example in the area of "permitted resolutions" or GOP values that are too extreme. MVCD / KVCD, for example, are primarily CD formats (VCD). The DVD-Video specification is much stricter and may lead to playback errors. This varies a lot depending on the DVD player model.
Development of the format
The XVCD format was developed and invented by Thomas Steg in Karlsruhe in February 2000.
The background to the development was the first availability of cheap Far Eastern DVD players, which were not limited to playing back pressed DVDs and video CDs, but could also play home-burned video CDs, MP3 files and pictures for the first time. One of the first multi-format players to appear on the market across the board was the Yamakawa AVPhile 713/715 (consisting primarily of PC components). The device was not so careful when playing non-compliant CDs, while other standard DVD players immediately rejected self-burned blank discs. Due to the growing fan base of the player, the desire arose to burn and play higher resolution and own video material.
The biggest hurdle, however, was the refusal of common burning programs at the time to be able to burn non-compliant Video CD data streams. In lengthy research on all burning programs available on the market, Thomas Steg succeeded in removing this lock by exchanging a certain, older DLL of the CD burning program NTI-CDMaker, so that any format that did not conform to Video CD could be burned. Even a mix of MPEG2-Stream, burned as MPEG1 Video-CD was possible (= XSVCD - eXtended Super Video-CD).
After a long series of tests, the solution for creating an XVCD was first made available to the public on the DVD board in the spring of 2000 and the newly selected video CD standard was given the name XVCD (eXtended Video CD). From there, the creation of an XVCD with better image quality and higher data rate soon spread around the world. Manufacturers of the devices that followed generously advertised their support for the XVCD standard , trade magazines wrote instructions for creating such CDs and updates to current burning programs finally allowed non-compliant video files.
However, since the use of the MPEG1 format with high data rates overwhelmed many standard players and the SVCD format based on MPEG2, as well as the playback of DivX AVI files slowly spread, the creation / burning of these drilled-out video files became over time and is no longer used today. Likewise, the availability of DVD burners for home users has displaced the use of self-made video CDs.