Xvid is a primary competitor of the DivX Pro Codec. In contrast with the DivX codec, which is proprietary software developed by DivX, Inc., Xvid is free software distributed under the terms of the GNU General Public License.
Xvid is a video codec for PC, whereas codec is an abbreviation for [co]der/[dec]oder, hence describes a program to encode and decode digital video.
The purpose of encoding video data is to reduce redundancies – that means to make it smaller for faster transmission over computer networks or for more efficient storage on computer disks.
Hence, Xvid can somewhat be seen as a ZIP for video. But unlike ZIP, Xvid is not lossless. That means that a video after compression and decompression with Xvid won't be identical to the original source.
Typically however, a difference to the source is visually imperceptible.
So Xvid removes information that is not important for human perception, which is somewhat similar to MP3 for audio. This enables very high compression rates that allow to effectively work with digital video on home computers at all. To give an example: uncompressed digital video is huge and requires about 100 GB per hour at PAL resolution. The same video would require just 500 MB per hour at very high quality when compressed with Xvid. That is a compression ratio of 200:1.
Main features of Xvid 1.4
- MPEG-4 Video Codec library
- Optimized for highest picture quality and archival purposes
- SP/ASP de-/encoding support
- Open-source software released under GPL license
- Primary platform PC (Windows and Linux)
- High-performance due to extensive assembly optimizations
- Jawor's stable builds are built on 24.06.2011 while the unstable builds are built on 13.07.2011.
- Jawor's patched build
includes Xvid EncRaw while x86 & x64
version and x64
version have a 64-bit DirectShow decoder.
Changes in Xvid Video Codec 1.3.3
- Improved MinGW and Cygwin compilation support
- Fixed possible encoder crash when Turbo+BVHQ+Qpel options are combined
- Added support for GNU Hurd as target OS
- Patch for QNX support
- Fix for possible overflow in Trellis quantization
* VFW frontend
- Minor GUI changes
* DShow/MFT frontend
- GUI cosmetics
- Switchable tray icon
* Example programs
- Fixed bug in xvid_encraw PGM header parser
- Fix out of bound access to framestats struct in xvid_encraw
It uses ASP features such as b-frames, global and quarter pixel motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices.