amazon-ivs-react-native-player ,Video width and height not getting on video load

When a player first connects to an Amazon IVS channel, it will retrieve the top level manifest (https://<ivs_channel_path>.channel.<channel_id>.m3u8) which will contain descriptions of the number of streams and the resolution for each stream. Then players will retrieve a playlist for the stream it will be playing, which will contain segment lists with durations or byte range lists. Players will seamlessly switch which between different streams (each with a separate bitrate and resolution) based on the perceived BW connection available at the time.

It is unclear where the onLoad command you are reference is occurring in this process. You may need to look back to the initial player connection for the resolutions of streams.