DivX® Codec 6.8.2 Released!
DivX Codec 6.8 introduced two major improvements over older versions - multithreaded decoding and support for custom quantization matrices. In addition, DivX Codec 6.8.2 will contain fixes for several issues reported to us since the 6.8 release, including better support for dual monitors and for older DivX files.
This article has been updated to reflect the official release of DivX Codec 6.8.2 as part of the DivX for Windows bundle on the DivX.com website.
DivX Codec has long featured multi-threading for improved performance on hyperthreaded, dual core or multi-processor systems, but we continue to optimize the codec further over time, and DivX 6.8 brought significant performance gains in the decoder.
In the chart below, we took a full-frame PAL source and encoded it at quantizer 2 with I/P frames to represent a very high bitrate DivX file, and quantizer 6 with I/P/B frames to represent more commonly encountered DivX video. We then made some minor modifications to VirtualDub to record in miliseconds the average time required to decode these two bitstreams over three passes with all other non-critical processes closed on our test machine, a Dell Preceision M90 featuring the Intel Centrino Duo.
The chart shows that in our test when we disabled post-processing and compared the time taken by DivX Codec 6.7 against DivX Codec 6.8.2 for the clip encoded at Q2, DivX Codec 6.8.2 performed 37% faster. DivX Codec 6.8.2 clearly outpaces 6.7 even when full deblocking with sharpening is enabled, the most taxing of all post-processing settings.
Custom quantization matrices
DivX 6.8 also introduced custom quantization matrices as an option in the encoder when using either of the HD profiles or unconstrained mode. Quantization matrices control the way information about the picture is subtly degraded as it undergoes parts of the lossy compression process. By loading different matrices you can influence how high and low frequency components of each block are adjusted, biasing data allocation towards flat or textured surfaces. This can lead to improved quality for certain types of content, such as anime, CGI, certain stylized works, and so on.
DivX Codec can load both CQM and XCM format matrix files, so you can leverage a large volume of matrices already created by the digital video community (see link to "qmatrix.zip" in this thread at Doom9.org, for example). We really like LigH's Custom Quantization Matrix Editor, which lets you easily edit files in both of these formats and visualize the matrices in 3D. You can edit both the intraframe matrix (used for I-frames, or "key-frames") and the interframe matrix (used for P/B frames, or "delta-frames"). LigH's help file also explains quantization matrices in more technical detail, so be sure to check it out. Best of all, many older versions of the DivX decoder already load custom matrices, so you should not run into compatibility issues with this new feature.
What's fixed in 6.8.2
- When videos that have non-square aspect ratios are moved across dual monitors the aspect ratio is now correctly preserved.
- It is now possible to play DivX 3.11 videos when "Use advanced hardware overlay" is enabled in the decoder configuration utility.
- Custom quantization matrices containing the ASCII end-of-file character are now loaded correctly.
- The "Browse Matrices" button in the encoder UI is now available consistently when the quantization type is set to "MPEG-2 Custom".
- The codec should no longer output licensing messages to the console. Thanks to BitBasher over at Doom9.org for getting in touch about this problem!
DivX Codec 6.8.2 is part of the DivX for Windows package and can be installed on top of any prior version of DivX to update it. If you are a registered user of DivX 6 your registration will be retained if you choose to try this beta or if you choose to re-install the last official release of DivX for Windows.
- Download DivX Codec 6.8.2 now (15.7MB)