In FLV streams, cue points are received via the normal Flash/FLV conventions, via an in-stream onCuePoint event. The cue point type is the cue point's name field, and all other attributes are sent as a flat list of key/value pairs in the cue point's parameters field.
Depending on the stream's configuration, cue points may be received in STWCue or AndoXML formats. See Cue Point Formats for details.
Players using a standard Flash implementation will hook to the NetStream.onCuePoint event to receive cue points. API details are documented here: NetStream.onCuePoint (AS3 Reference).
Players decoding the FLV stream themselves (i.e., outside the Flash environment) can refer to the FLV File Format Specification for details.
In addition, the FLV transport supports an additional feature: cue point previews. This allows players to see upcoming cue points in order to fetch resources and prepare playback before the actual cue point. Cue point previews are sent via the non-standard onCuePointPreview and onCuePointPreviewExpired events. Not all cue points are "previewed" – only cue points that are deemed "expensive" to setup for playback (mostly, video mid-rolls).