In our opinion, XviD is the best MPEG-4 video codec.
We have compared many examples using WMV9, Xvid and DivX codecs, and came to a conclusion that video created with XviD codec has the best quality.
Let's look at each codec in more detail...
We have compressed a video clip using 3 different codecs with the same settings (resolution: 320x240):
Codec #1: XviD v1.1 - bitrate: 780 kbps, profile: home theatre profile level, single pass
Codec #2: Windows Media Video v9 - bitrate: ~780 kbps
Codec #3: DivX v6.4 - bitrate: 780 kbps, profile: home theatre profile, single pass
XviD codec produces industry-leading compact high quality MPEG-4 video. Its quality and efficiency has made it one of the most popular video codecs online. The XviD codec is developed and maintained by a handful of skilled and interested engineers from all over the world. Playback of XviD movies is usually supported in new DVD players nowadays. This codec makes it possible to compress a full-length DVD-quality movie enough to fit on a single CD, while still maintaining high image quality. The video is usually combined with MP3 or AC3 audio.
Quality: XviD maintains good detail, keeps the background and faces smooth. It looks very good when the clip is in motion.
Pros: Free, excellent image quality, support in consumer electronics devices, good encoding speed.
Summary: An excellent choice for playback and for video encoding.
Microsoft Windows Media Video 9
Microsoft's video codec makes vast improvements over that from series 8, and more importantly, the decode stream parameters are now fixed – future iterations of Windows Media Video will make improvements in the encoder, but those will be able to play back on devices that are WMV9 compatible. This has enabled them to find support in several new and a great many upcoming DVD players, digital media adapters, and portable video players.
Quality: WMV9 does a good job as XviD, with about the same level of detail. Usually, WMV9 clips doesn't have compression artifacts around the edges, but video is slightly "soft" with a bit less definition. It looks excellent and the problems virtually melt away when the clip is in motion.
Pros: Free Windows encoder, excellent image quality, support in consumer electronics devices and portables.
Cons: Average encoding speed.
Summary: Though slower, this codec produces video with good quality.
The codec from DivX, Inc is popular online, and has even found its way into several consumer electronics devices. DivX ;-) 3.11 alpha refers to a hacked version of the Microsoft MPEG-4 Version 3 video codec, extracted around 1998 by French hacker Jerome Rota (also known as Gej). In early 2000, Rota created a company to improve the codec development. Free versions of DivX Pro before 5.2 typically contained spyware. From 5.2 onwards, including version 6.4, no spyware was included, but Pro version (with DivX encoder) is only available in the form of a paid release.
Quality: DivX isn't quite as sharp as the source material. There are noticeable compression artifacts around the edges of objects - still present when the video is in motion. The background isn't as smooth as it should be.
Pros: Good encoding speed, support in consumer electronics devices.
Cons: Not free.
Summary: The quality of video produced by this codec is not bad.
Of course, quality isn't the only factor when it comes to personal video encoding. It's a processor-intensive task that can take quite a long time. Let's take a quick look at the encoding time for these three codecs:
780KBit Encoding Times (Pentium 4 3GHz CPU), Clip Duration: 1 min, resolution: 576x320
Certainly both codecs – XviD and DivX – are fast.
The best codecs are XviD and Windows Media Video 9 -- it all depends on your priorities. If you're going to stick to computers as playback devices, the faster speed and excellent image quality of XviD is welcome. If you want to play your stuff on the PDAs, portable video players, and DVD players, WMV9 has broader industry support and is worth the extra encoding time. Both codecs delivered quite impressive image quality.
It's difficult to say whether XviD or Windows Media Video 9 looks better. It's safe to make the generalization that the XviD encoded clips tend to have a touch more detail. On the whole, watching the clips in motion and scrutinizing details over and over, it's hard to recommend one over the other. XviD certainly encodes faster, which can be a real concern when compressing large video clips. WMV9, on the other hand, has found its way into several consumer electronics devices, with a great many more on the way. The XviD codec is also available in consumer electronics devices, but support for WMV9 in DVD players, portable video players, and home media gateways is certainly stronger.