The ID3 tag gives you the length of the track only for the part that has been loaded.

ID 3标签只能给出已载入部分的音轨时长。

youdao

For example: if you've got a track of 240 seconds that has only been loaded halfway, ActionScript will return 120 seconds for the length property of the sound.

例如：一段时长240秒的音轨，如果只载入了一半，ActionScript的音频长度属性将会返回120秒。

youdao

The main experimental parameters studied were the loaded area and the concrete filled length.

试验的主要参数为局部承压面积和管内混凝土填充长度。

youdao

Available as a bonus loaned exclusively to U.S. customers purchasing the Sony 4K LED TV, the video player comes loaded with content, including both full length Hollywood features and a gallery of videos, creating the first true home 4K experience.

ENGADGET: Sony's 4K Ultra HD Video Player revealed, COO Phil Molyneux tells us what 'only Sony can do'

If you follow a road, the M1 for example, along its length, the map will automatically load new crash locations as fresh sections of the map are loaded.

BBC: Crash: About the road fatality data