记录一下，可以在线查询mp4编码格式的网站：
https://gpac.github.io/mp4box.js/test/filereader.html
通常H264的格式的文件编码信息如下：
Movie Info
File Size / Bitrate： 0 bytes / 0 kbps
Duration / Timescale： 220845/1000 (0:03:40.845)
Brands (major/compatible)： isom,isom,iso2,avc1,mp41
MIME： video/mp4; codecs="avc1.42c01f,mp4a.40.2"; profiles="isom,iso2,avc1,mp41"
Progressive： false
Fragmented： false
MPEG-4 IOD： false
重点查看MIME类型是否为video/mp4，是否包含avc信息。且 Progressive/Fragmented/MPEG-4 IOD 三个参数为false。
另外iOS支持的编码格式可以通过官方查看：
https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/FrequentlyAskedQuestions/FrequentlyAskedQuestions.html
What are the specifics of the video and audio formats supported?
Although the protocol specification does not limit the video and audio formats, the current Apple implementation supports the following formats:
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)