[Feature] Add long video demo

[HypnosXC]

No description provided.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #274 (88415a9) into master (bd9b725) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #274   +/-   ##
=======================================
  Coverage   86.30%   86.30%           
=======================================
  Files          98       98           
  Lines        6921     6921           
  Branches     1118     1118           
=======================================
  Hits         5973     5973           
  Misses        730      730           
  Partials      218      218           

Flag	Coverage Δ
unittests	86.28% <ø> (ø)

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[dreamerlin]

This PR is still in progress since there are many code lines can be improved.

[OpenMMLab-Assistant-007]

Hi!
@HypnosXC
First of all, we want to express our gratitude for your significant PR in the OpenMMLab project. Your contribution is highly appreciated, and we are grateful for your efforts in helping improve this open-source project during your personal time. We believe that many developers will benefit from your PR.

We would also like to invite you to join our Special Interest Group (SIG) private channel on Discord, where you can share your experiences, ideas, and build connections with like-minded peers. To join the SIG channel, simply message moderator— OpenMMLab on Discord or briefly share your open-source contributions in the #introductions channel and we will assist you. Look forward to seeing you there! Join us ：https://discord.gg/UjgXkPWNqA

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Thank you again for your contribution❤