What is a OGA file?
Ogg audio container with Vorbis encoding
OGA files contain only the audio elements of an OGG file. It’s a container format that contains the audio transport stream encoded in the Vorbis format and is the preferred extension for audio-only OGG files.
The OGG file format is an open-source, and royalty-free file format framework. Ogg is an open and standardized bitstream container format designed for streaming and manipulation. It was developed by the Xiph.Org Foundation. The file format can multiplex a number of separate independent open source CODECs for audio, video and text (e.g., subtitles). It usually contains the Vorbis or FLAC audio CODEC. OGA files are typically associated with OGG files and are used when only the audio needs to be sent and not an entire movie.