苹果官方文档中对 ios 能支持的压缩级别进行了描述：

https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/FrequentlyAskedQuestions/FrequentlyAskedQuestions.html 

Video:

H.264 Baseline Level 3.0, Baseline Level 3.1, Main Level 3.1, and High Profile Level 4.1.
Audio:

HE-AAC or AAC-LC up to 48 kHz, stereo audio
MP3 (MPEG-1 Audio Layer 3) 8 kHz to 48 kHz, stereo audio
AC-3 (for Apple TV, in pass-through mode only)

安卓其实都是支持的，就按这个标准压就好了。

ffmpeg -i "input.mp4" -c:v libx264 -profile:v high -level:v 4.1 -c:a aac oupput.mp4