Audio and video payload on React sites

Sites with 500 KB to 3 MB of audio/video media audio and video payload have a good LCP most often: 89%, against 84% of all React sites. Sites with no audio or video requests media payload have it least often, at 84%.

Sites with over 3 MB of audio/video media audio and video payload have a good INP most often: 97%, against 92% of all React sites. Sites with 500 KB to 3 MB of audio/video media media payload have it least often, at 92%.

No audio or video requests is the most used: 80.8% of React sites. 500 KB to 3 MB of audio/video media is 2.8% of React sites.

Across the four LCP sub-parts in Chrome's field data, the largest gap between 500 KB to 3 MB of audio/video media and no audio or video requests sits in time to first byte (TTFB): 477 ms median for 500 KB to 3 MB of audio/video media against 512 ms for no audio or video requests. Overall median field LCP is 1.3s for 500 KB to 3 MB of audio/video media (TTFB 477 ms, load delay 453 ms, load duration 132 ms, render delay 173 ms) versus 1.4s for no audio or video requests.

Across the four LCP sub-parts in Chrome's field data, the largest gap between 500 KB to 3 MB of audio/video media and no audio or video requests sits in time to first byte (TTFB): 477 ms median for 500 KB to 3 MB of audio/video media against 512 ms for no audio or video requests. Overall median field LCP is 1.3s for 500 KB to 3 MB of audio/video media (TTFB 477 ms, load delay 453 ms, load duration 132 ms, render delay 173 ms) versus 1.4s for no audio or video requests.

On Wix, 76% of sites use no audio or video requests audio and video payload, and 94% of Wix sites have a good LCP, against 84% of all sites. On WordPress, 85% of sites use no audio or video requests, and 63% of WordPress sites have a good LCP.

On Wix, 76% of sites use no audio or video requests audio and video payload, and 96% of Wix sites have a good INP, against 92% of all sites. On WordPress, 85% of sites use no audio or video requests, and 96% of WordPress sites have a good INP.

PlatformAudio and video payload on its sitesGood LCP

All React sites 9,570 sitesNo audio/video media 81%Light media (under 500 KB) 12%84%

Wix 5,824 sitesNo audio/video media 76%Light media (under 500 KB) 14%94%

WordPress 2,342 sitesNo audio/video media 85%Light media (under 500 KB) 11%63%

No audio/video media Light media (under 500 KB) Heavy media (over 3 MB) Medium media (500 KB to 3 MB)

Does the platform explain the audio and video payload difference?

On Wix, 93% of sites with 500 KB to 3 MB of audio/video media audio and video payload have a good LCP, against 95% of Wix sites with no audio or video requests. Within Wix, sites with 500 KB to 3 MB of audio/video media and no audio or video requests have a good LCP about equally often. On WordPress, 63% of sites with no audio or video requests audio and video payload have a good LCP, against 66% of WordPress sites with under 500 KB of audio/video media. Within WordPress, sites with no audio or video requests and under 500 KB of audio/video media have a good LCP about equally often.

On Wix, 98% of sites with over 3 MB of audio/video media audio and video payload have a good INP, against 97% of Wix sites with no audio or video requests. Within Wix, sites with over 3 MB of audio/video media and no audio or video requests have a good INP about equally often. On WordPress, 96% of sites with no audio or video requests audio and video payload have a good INP, against 94% of WordPress sites with under 500 KB of audio/video media. Within WordPress, sites with no audio or video requests and under 500 KB of audio/video media have a good INP about equally often.

How autoplaying video streams saturate initial bandwidth

When a <video> tag loads without preload="none" or an optimized poster image, the browser fetches megabytes of video segments concurrently with critical stylesheets and hero assets. Across 7,730 sites (80.8%) with no initial media requests, 84% pass field LCP at a 1.4s median, versus 86% (1.4s median) under 500 KB and 85% (1.4s median) above 3 MB.