From Amazon Transcribe FAQs – Amazon Web Services (AWS):
What kind of inputs does Amazon Transcribe support?
Amazon Transcribe supports both 16 kHz and 8kHz audio streams, and multiple audio encodings, including WAV, MP3, MP4 and FLAC.
Since Amazon Transcribe is a service for converting spoken speech into text, it would be best to provide it with an audio file rather than a video.
If you convert that 4.3 GB video into an audio file, it will probably be small enough to use with Amazon Transcribe. If you require a service to perform that conversion, you could use Amazon Elastic Transcoder.