Now if you want to use the video tag in the page, you need to consider three situations: those that support Ogg Theora or VP8 (if nothing happens to this thing) (Opera, Mozilla, Chrome), and those that support H.264 (Safari, IE 9, Chrome), are not supported (IE6, 7, 8). Okay, now let's understand HTML 5 video from a technical level, including the use of video tags, media properties and methods that can be used by video objects, and media events.
Use of Video tag
The Video tag contains several attributes such as src, poster, preload, autoplay, loop, controls, width, height, etc., as well as an internally used tag
(1) src attribute and poster attribute
You can imagine what the src attribute is used for. Like the tag, this attribute is used to specify the address of the video. The poster attribute is used to specify a picture to be displayed (preview picture) when the current video data is invalid. Invalid video data may mean that the video is loading, the video address may be incorrect, etc.
<video width="658" height="444" src="http://www.youname.com/images/first.mp4" poster="http://www.youname.com/images/first.png" autoplay="autoplay"></video>
(2) preload attribute
The use of this attribute can also be understood by its name. This attribute is used to define whether the video is preloaded. The attribute has three optional values: none, metadata, and auto. If this attribute is not used, the default is auto.
<video width="658" height="444" src="http://www.youname.com/images/first.mp4" poster="http://www.youname.com/images/first.png" autoplay="autoplay" preload="none"></video>
None: No preloading. Using this attribute value, it is possible that the page author believes that the user does not expect this video, or to reduce the HTTP request.
Metadata: Partially preloaded. Using this attribute value means that the page author believes that the user does not expect this video, but provides the user with some metadata (including dimensions, first frame, track list, duration, etc.).
Auto: All preloaded.
(3) autoplay attribute
is another attribute whose use can be known by looking at its name. The Autoplay attribute is used to set whether the video plays automatically. It is a Boolean attribute. When it appears, it means automatic playback. If it is removed, it means not automatic playback.
<video width="658" height="444" src="http://www.youname.com/images/first.mp4" poster="http://www.youname.com/images/first.png" autoplay="autoplay" preload="none"></video>
Note that the values of Boolean attributes in HTML are not true and false. The correct usage is to use this attribute in a tag to indicate true. At this time, the attribute either has no value or its value is equal to its name (here, autoplay is or ); and not using this attribute in the tag means false (not autoplaying here is ).
(4) loop attribute
<video width="658" height="444" src="http://www.youname.com/images/first.mp4" poster="http://www.youname.com/images/first.png" autoplay="autoplay" loop="loop"></video>
It is clear at a glance that the loop attribute is used to specify whether the video is played in a loop. It is also a Boolean attribute.
(5) controls attribute
<video width="658" height="444" src="http://www.youname.com/images/first.mp4" poster="http://www.youname.com/images/first.png" autoplay="autoplay" preload="none" controls="controls"></video>
The Controls attribute is used to indicate to the browser that the page author did not use a script to generate a playback controller and requires the browser to enable its own playback control bar.
The control bar must include playback pause control, playback progress control, volume control, etc.
The default playback control bar of each browser is different in the interface. Due to a weird problem with my browser, the Video tags of Firefox and Safari are not working properly, so I can only find screenshots of these two online.
(6) The width attribute and height attribute
are common attributes of tags. Needless to say more about this.
(7) source tag
<video width="658" height="444" poster="http://www.youname.com/images/first.png" autoplay="autoplay" preload="none" controls="controls"><source src="http://www.youname.com/images/first.ogv" /><source src="http://www.youname.com/images/first.ogg" /></video>
The Source tag is used to specify multiple selectable (because the audio tag can also contain this tag, so media is used here instead of video) The browser can ultimately only select one) file address, and it can only be used when the media tag does not use the src attribute.
The browser checks whether the video specified by the tag can be played in the order of the source tag (the video format may not be supported, the video does not exist, etc.). If it cannot be played, change to the next one. This method is mostly used to be compatible with different browsers. The Source tag itself does not mean anything and cannot appear alone.
This tag contains three attributes: src, type, and media.
src attribute: used to specify the address of the media, the same as the video tag.
Type attribute: Used to describe the type of media specified by the src attribute, helping the browser determine whether it supports this category of media formats before obtaining the media.
Media attribute: Used to describe the medium in which the media is used. If not set, the default value is all, indicating that all media are supported. Have you thought about the media attribute of the
