getDuration return error time

[VeiZhang]

Before filing a bug:

• Search existing issues, including issues that are closed:
  SimpleExoPlayer getDuration some audio links are getting incorrectly #6241 getDuration() return wrong value on audio mp3 since 2.9.3 #6238

[REQUIRED] Issue description

Using ExoPlayer to play some videos, I found some of them get the wrong duration, always return -1, so I can't seek.

[REQUIRED] Reproduction steps

Using the ExoPlayer demo app, replace Cats -> Dogs uri in media.exolist.json playlist with the test link content.

[REQUIRED] Link to test content

I couldn't upload to my repository, please download from https://mbf.me/Tqk7HX , it is a local video file, not online

[REQUIRED] Version of ExoPlayer being used

the latest.

[REQUIRED] Device(s) and version(s) of Android being used

Amlogic, android7.1

[google-oss-bot]

This issue does not seem to follow the issue template. Make sure you provide all the required information.

[tonihei]

Some streams don't provide the duration or seek information in the header data and that's why we need to play to the end before knowing the actual duration.

The actual value of getDuration is C.TIME_UNSET as documented on the method.