Matroska!

Ogg Vorbis is a fully open, general-purpose compressed audio format for mid to high quality (8kHz-48.0kHz, 16+ bit, polyphonic) audio and music at fixed and variable bitrates from 16 to 128 kbps/channel. This places Vorbis in the same competitive class as audio representations such as MPEG-4 (AAC), and similar to, but higher performance than MPEG-1/2 audio layer 3, MPEG-4 audio (TwinVQ), WMA and PAC.

Opus is a totally open, royalty-free, highly versatile audio codec. Opus is unmatched for interactive speech and music transmission over the Internet, but also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716 which incorporated technology from Skype's SILK codec and Xiph.Org's CELT codec.

The CCCP was created to replace the video playback packs provided in favor of a single reliable pack capable of decoding practically anything.

ffdshow tryouts is a DirectShow and Video for Windows codec with support for a wide range of audio and video formats, such as Xvid, DivX, and H.264. It includes a powerful filter set that can enhance the video quality - with filters for resizing, deinterlacing, and displaying subtitles - as well as audio quality through normalization, down-/upmixing, and resampling.

Xvid is an open-source research project focusing on video compression and is a collaborative development effort. All code is released under the terms of the GNU GPL license.

LAV Filters are a set of open-source DirectShow filters, aimed to eventually replace the better part of the playback chain required to play all and any modern media.

WavPack is a completely open audio compression format providing lossless, high-quality lossy, and a unique hybrid compression mode. Although the technology is loosely based on previous versions of WavPack, the new version 4 format has been designed from the ground up to offer unparalleled performance and functionality.

Apple Lossless (also known as ALAC) is an audio codec developed by Apple Inc. for lossless data compression of digital music.

Nero AAC reference quality MPEG-4 and 3GPP audio codec

»TAK – [T]om’s lossless [a]udio [k]ompressor / [T]oms verlustfreier [A]udio[k]ompressor – is, as the name already suggests, a lossless audio compressor, similar to FLAC, WavPack and Monkey’s Audio. On average, lossless compression reduces the file size to about 50 percent of the original size; however the compression can vary between approximately 30 and 70 percent, depending on the file. Decompression restores a bit identical copy of the original audio data (that's why we call it lossless). »

Satsuki Decoder Pack is an audio/video auto-installable filters and decoder for windows 2k/XP/2k3/2k8/vista/seven/8 (French, English).The purpose of this pack is to decode most of video files.This pack contain only filters and decoders (with some exeptions), it avoid conflict.This pack is free with no spyware or adware.