Some features of Lagarith Lossless Video Codec 1.3 :
Lagarith is able to operate in several colorspaces - RGB24, RGB32, RGBA, YUY2, and YV12. Also, Lagarith will never down-sample video, preventing inadvertent quality loss. For DVD video, the compression is typically only 10-30% better than Huffyuv. However, for high static scenes or highly compressible scenes, Lagarith significantly outperforms Huffyuv. A comparison for various types of video can be found here.
Lagarith is able to outperform Huffyuv due to the fact that it uses a much better compression method. Pixel values are first predicted using median prediction (the same method used when "Predict Median" is selected in Huffyuv). This results in a much more compressible data stream. In Huffyuv, this byte stream would then be compress using Huffman compression. In Lagarith, the byte stream may be subjected to a modified Run Length Encoding if it will result in better compression. The resulting byte stream from that is then compressed using Arithmetic compression, which, unlike Huffman compression, can use fractional bits to encode a symbol. This allows the compressed size to be very close to the entropy of the data, and is why Lagarith can compress simple frames much better than Huffyuv, and avoid expanding high static video. Additionally, Lagarith has support for null frames; if the previous frame is mathematically identical to the current, the current frame is discarded and the decoder will simply use the previous frame again.
The trade-off for this improved compression is speed. Lagarith is significantly slower than Huffyuv on typical video. On my system, Lagarith tends to encode at about half the speed Huffyuv does. Additionally, the decode speed is slower than the encode speed; this is due to the nature of Arithmetic compression and the prediction algorithm. Fortunately, for the situations where the codec offers the most advantages over Huffyuv, the speed difference between the two tends to decrease, and Lagarith can be much faster for simple video.
This codec was build using the Huffyuv source as a template, and uses some Huffyuv code, most notably the routine to upsample YUY2 video to RGB. The function for upsampling YV12 to YUY2 was taken from AviSynth.
How to install Lagarith Lossless Video Codec :
- Uncompress the files from archive, right-click on the lagarith.inf file and select Install.
- That's all! Now check the installed codec. See Checking Installed VIDEO and AUDIO Codecs In Windows XP guide.
Changes in Lagarith Lossless Video Codec 1.3.19 :
- Fixed a race condition introduced in 1.3.18 that could cause corrupted RGBA video when using multithreading. Thanks to Jason Hamby and Sander for reporting this.
- Fixed a crash that could occur when decoding odd width RGBA with a height greater than 512. Thanks to Sander for reporting this and providing a sample video for debugging.
• Related downloads:
- MSU Lossless Video Codec: easy-to-use and understand interface.
- HuffYUV: is a very fast, lossless Win32 video codec.
- Arithyuv: is a lossless video codec designed for video capturing.
- Helix YUV Codecs: are two almost identical Video for Windows compatible codecs for decompressing/viewing I420 and YV12 AVI files or the output of AviSynth scripts...
- TechSmith Screen Capture Codec: is a lossless video codec optimized for screen recording.