Free lossless software for windows

Alparysoft Lossless Video Codec is for encoding and decoding of video Without any mathematical losses (i.e. source and destination video are absolutely identical after encoding/decoding process), the compression ratio is twice - 5 times Without any visual losses.

Onda Lossless Audio Compressor is a Java program that compresses 16-bit and 24-bit WAVE and AIFF audio files using the Onda lossless audio compression (LAC) algorithm.
The Onda Lossless Audio Compressor algorithm doesnt perform as well as some other open-source LAC algorithms in terms of either speed or compression ratio; its virtue, if it can be said to have one, is that it is easy to understand and to implement, involving no mathematics beyond a bit of arithmetic.
The motivation for publishing the Onda Lossless Audio Compressor algorithm is that there may be circumstances in which a mediocre but simple LAC algorithm thats easy to implement is preferable to a good but complex algorithm.
There is a diminishing return on the complexity of LAC algorithms; each extra percentage point of compression becomes increasingly difficult to achieve.
The Onda Lossless Audio Compressor algorithm is content with the easy pickings: it gives up the struggle for extra compression when the going gets tough, with the expectation that its less-than-stellar performance will be sufficient for some purposes.
Main features:
- It can compress 16-bit and 24-bit AIFF and WAVE audio files, and can validate and expand files that it has compressed.
- It can be used as a command-line (console) application or with a graphical user interface (GUI).
- It can operate on single files or on all the files in a directory, with optional recursion. Input files and directories can be specified directly or as a list of pathnames in a text file.
- When it is run as a GUI application, input files and directories can be specified by drag-and-drop on systems that support it.
- It can preserve the ancillary chunks of AIFF and WAVE files (eg, the "bext" chunk used in BWF files), using a filter to specify the chunks that should be included in or excluded from a compressed file.

The Lagarith Lossless Video Codec was designed to be used in editing and archiving. Lagarith offers better compression than codecs like Huffyuv, Alparysoft, and CorePNG. There are a few lossless codecs that can compress better than Lagarith, such as MSU and FFV1; however Lagarith tends to be faster and stabler than these codecs.

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. For multiple processor systems, Lagarith 1.3.0 can take advantage of additional processors; while Huffyuv cannot. On such systems Lagarith may be faster than Huffyuv.
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 and to perform pixel prediction on YUY2 video. Other colorspace conversion routines were taken from AviSynth.

Major Features:

1. Lagarith is able to operate in several colorspaces - RGB24, RGB32, RGBA, YUY2, and YV12. 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.
2. 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.
3. 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 per 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.
4. 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.
5. On a single processor system, Lagarith can be significantly slower than Huffyuv on typical video. Additionally, the decode speed tends to be slower than the encode speed; this is due to the nature of Arithmetic compression and the prediction algorithm.

Enhancements

• Fixed a bug that would cause the codec to crash when attempting to upsample YUY2 video with a width that was not a multiple of 4. Thanks to Zack Hartmann for reporting this and providing a sample video.
• Fixed a bug that prevented the configure dialog from showing up in Sony Vegas. Thanks to Adam S. for reporting this.
• Added a configure option to prevent Lagarith from upsampling video when decoding. Checking this option and having the mode set to RGB or RGBA will prevent Lagarith from performing any colorspace conversions. Thanks to Andrew Harrison for suggesting this option.