# Smart block track length criteria

**URL:** <https://discourse.libretime.org/t/smart-block-track-length-criteria/818>\
**Category:** Get Help\
**Created:** [March 1, 2021, 9:22pm UTC](https://discourse.libretime.org/t/smart-block-track-length-criteria/818 "2021-03-01T21:22:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![davorin](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.libretime.org/davorin/32/447_2.png) [@davorin](https://discourse.libretime.org/u/davorin)\
**Post date:** [March 1, 2021, 9:22pm UTC](https://discourse.libretime.org/t/smart-block-track-length-criteria/818/1 "2021-03-01T21:22:54Z")

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Good evening

How should the track length criteria work for smart blocks?

Even when entering length \> 0 and pressing preview I don’t see any results…

So what is the exact format for the track length specifier?

thanks in advance  
richard

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<div class="post-metadata">

**Author:** ![davorin](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.libretime.org/davorin/32/447_2.png) [@davorin](https://discourse.libretime.org/u/davorin)\
**Post date:** [March 1, 2021, 9:57pm UTC](https://discourse.libretime.org/t/smart-block-track-length-criteria/818/2 "2021-03-01T21:57:11Z")

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Ah got it…must be in the hh:mm:ss firmat,

But what still puzzles me:

When I set the Limit to 24 hours and press the preview button, the duration is always shown as ~24:00:00.0, even when there are only a few tracks…

So how can I see the total length it uses?