Every transcription tool I tried wanted an MP3 first. My voice memos were m4a, my interviews were mp4, and converting before upload was the step that cost time and quietly lost quality. ScribVoice takes WAV, MP3, M4A and MP4 directly, with speaker labels, timestamps, and SRT or DOCX export in 38 spoken languages. 30 minutes free without an account. Paid starts at $9/month for 1,200 minutes.