What is ASF file?

Advanced Systems Format
File extension: .asf
MIME type: video/x-ms-asf
Type code: 'ASF_'
Uniform Type Identifier: com.microsoft.advanced-​systems-format
Magic: 30 26 b2 75
Developed by: Microsoft
Type of format: Container format
Container for: WMA, WMV, MPEG4 etc.

What is OGG file?

File extension: .ogg
MIME type: application/ogg
Magic: OggS
Developed by: Xiph.Org Foundation
Type of format: Container format
Container for: Vorbis, Theora, Speex, FLAC

Ogg is an open standard for a free container format for digital multimedia, unrestricted by software patents and designed for efficient streaming and manipulation. Ogg is maintained by the  Xiph.Org Foundation.

Convert ASF to OGG with Mini-stream Ripper