# Difference between Normal and Preview video elements **URL:** \ **Category:** macOS\ **Created:** [March 3, 2021, 6:39am UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722 "2021-03-03T06:39:27Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![richard1](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/richard1/32/5472_2.png) [@richard1](https://devforum.zoom.us/u/richard1)\ **Post date:** [March 3, 2021, 6:39am UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/1 "2021-03-03T06:39:28Z")
Hello I’m building out some functionality with custom UI and am trying to understand the limitations of using ‘normal’ video elements. Are there restrictions on the number of normal video elements which can be rendered concurrently? Does the size of each element affect this and should the HD status of an element effect this? Also, can you confirm what the ‘resize’ method does under the hood? Thanks Richard ---
**Author:** ![jon.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jon.zoom/32/13495_2.png) [@jon.zoom](https://devforum.zoom.us/u/jon.zoom)\ **Post date:** [March 3, 2021, 5:54pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/2 "2021-03-03T17:54:09Z")
Hi @richard1, thanks for the post. The preview element is used for previewing your own video (e.g. setting virtual backgrounds, video preview window before joining a meeting). The normal element is for displaying regular in-meeting video. > Are there restrictions on the number of normal video elements which can be rendered concurrently? Does the size of each element affect this and should the HD status of an element effect this? There are restrictions, but they are not based on the number of concurrent streams. The limit is based on the total bandwidth of all streams being received by your SDK instance. Usually this ends up being around 34 streams. Currently there is a known issue where, after exceeding the bandwidth limit, the SDK will silently fail for all additional streams you add. We are working on adding an explicit error code for this scenario. > Also, can you confirm what the ‘resize’ method does under the hood? I know that this is tied to some internal state representing the dimensions of the element, but I’m not 100% sure what the full implications of calling this method entail. I will need to investigate this one and get back to you. Thanks! ---
**Author:** ![richard1](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/richard1/32/5472_2.png) [@richard1](https://devforum.zoom.us/u/richard1)\ **Post date:** [March 3, 2021, 6:08pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/3 "2021-03-03T18:08:47Z")
Thanks Jon Is the bandwidth limit public and fixed? Or does it depend on network conditions? Richard ---
**Author:** ![jon.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jon.zoom/32/13495_2.png) [@jon.zoom](https://devforum.zoom.us/u/jon.zoom)\ **Post date:** [March 3, 2021, 9:20pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/4 "2021-03-03T21:20:28Z")
Hi @richard1, The bandwidth is fixed, but we do not have any public documentation on what the limit is at this time. Thanks! ---
**Author:** ![liminal\_andy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/liminal_andy/32/16222_2.png) [@liminal\_andy](https://devforum.zoom.us/u/liminal_andy)\ **Post date:** [March 3, 2021, 9:29pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/5 "2021-03-03T21:29:43Z")
Would it be safe to say that if I can render more feeds at 720p than I can at 360p, this would likely be an error and not intended behavior? ---
**Author:** ![jon.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jon.zoom/32/13495_2.png) [@jon.zoom](https://devforum.zoom.us/u/jon.zoom)\ **Post date:** [March 3, 2021, 10:20pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/6 "2021-03-03T22:20:59Z")
Hey @liminal_andy, It’s difficult to say for sure with this much information, but if you are actually seeing fewer streams at 360p than at 720p, then I’d say probably. If they were the same, it could have been something different. How many streams in each resolution are you able to see? Thanks! ---
**Author:** ![liminal\_andy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/liminal_andy/32/16222_2.png) [@liminal\_andy](https://devforum.zoom.us/u/liminal_andy)\ **Post date:** [March 3, 2021, 11:17pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/7 "2021-03-03T23:17:31Z")
That’s what I need to spend time determining, how many concurrent streams I can grab at each resolution step, and then what happens when I start mixing and matching. This is where documentation is really needed. It’s going to take hours to essentially reverse engineer Zoom’s bandwidth logic. ---
**Author:** ![jon.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jon.zoom/32/13495_2.png) [@jon.zoom](https://devforum.zoom.us/u/jon.zoom)\ **Post date:** [March 4, 2021, 7:14pm UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/8 "2021-03-04T19:14:13Z")
Hi @liminal_andy, Apologies for the inconvenience this causes. Hopefully the error code we will be adding for exceeding the bandwidth will be helpful in the future. Thanks! ---
**Author:** ![system](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/3X/6/1/614bdd549b610bbaa46ff934617683a02bdaa03c.png) [@system](https://devforum.zoom.us/u/system)\ **Post date:** [April 4, 2021, 5:14am UTC](https://devforum.zoom.us/t/difference-between-normal-and-preview-video-elements/44722/9 "2021-04-04T05:14:38Z")
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