record start; start of recording
Computing term for the action or command that begins recording data, audio, video, or logs.
Please press the record start button.
In this software, you can set the record start time.
記録停止 means 'record stop' or 'stop recording', the opposite action of 記録開始.
録画開始 is more specific to video recording, while 記録開始 can refer to any kind of recording (data, audio, etc.).
Compound of 記録 (record) and 開始 (start). A straightforward technical term.