OGG is a free audio container format developed by Xiph.Org Foundation. Its unrestricted design offers efficient manipulation and streaming of high-quality digital multimedia. It multiplexes multiple streams for video, audio, text, and metadata. OGG has a filename extension of .ogg, although it can also come in .ogv, .oga, .ogm, .opus, and .spx.
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HEVC MKV is a digital media format that uses HEVC codec, instead of the usual H.264, which is used on typical MKV files. HEVC MKV files are encoded at lower bitrates than H.264 MKV, making them smaller by up to 50%. However, software and hardware support for HEVC MKV files is quite limited as opposed to H.264 MKV, which ranks among the most popular media formats today.
VLC Media Player
MKV File Player