HTML5: video tag Why can't my video play?

Added this sentence to the page:

Reply to discussion (solution)

video The src playback file of this tag has been blocked due to browsing Different devices support different file formats. Moreover, video files must follow a certain encoding (such as: h264, etc.) before they can be played

Format issues, avi does not seem to support it currently, maybe I am ignorant
It depends on what browser you are using To give you an example

Can HTML5 be used without closing tags?

The format is incorrect and your avi

video tag is not supported The format of avi is not supported

Ogg = Ogg file with Theora video encoding and Vorbis audio encoding
MPEG4 = MPEG 4 file with H.264 video encoding and AAC audio encoding
WebM = WebM files with VP8 video encoding and Vorbis audio encoding
from Baidu.

Need to convert the format

A dark video area is out
====================== ========
The browser should be able to support html5,
but the video formats supported by html5 are limited, change to a supported format