Audio and video payload on React sites

Sites with under 500 KB of audio/video media audio and video payload have a good LCP most often: 80%, against 79% of all React sites. Sites with no audio or video requests media payload have it least often, at 78%.

Sites with under 500 KB of audio/video media audio and video payload have a good INP most often: 100%, against 99% of all React sites. Sites with no audio or video requests media payload have it least often, at 99%.

No audio or video requests is the most used: 80.8% of React sites. Under 500 KB of audio/video media is 11.8% of React sites.

Across the four LCP sub-parts in Chrome's field data, the largest gap between under 500 KB of audio/video media and no audio or video requests sits in time to first byte (TTFB): 670 ms median for under 500 KB of audio/video media against 735 ms for no audio or video requests. Overall median field LCP is 1.6s for under 500 KB of audio/video media (TTFB 670 ms, load delay 427 ms, load duration 176 ms, render delay 192 ms) versus 1.6s for no audio or video requests.

Across the four LCP sub-parts in Chrome's field data, the largest gap between under 500 KB of audio/video media and no audio or video requests sits in time to first byte (TTFB): 670 ms median for under 500 KB of audio/video media against 735 ms for no audio or video requests. Overall median field LCP is 1.6s for under 500 KB of audio/video media (TTFB 670 ms, load delay 427 ms, load duration 176 ms, render delay 192 ms) versus 1.6s for no audio or video requests.

On Wix, 76% of sites use no audio or video requests audio and video payload, and 92% of Wix sites have a good LCP, against 79% of all sites. On WordPress, 85% of sites use no audio or video requests, and 66% of WordPress sites have a good LCP.

On Wix, 76% of sites use no audio or video requests audio and video payload, and 100% of Wix sites have a good INP, against 99% of all sites. On WordPress, 85% of sites use no audio or video requests, and 100% 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%79%

Wix 5,824 sitesNo audio/video media 76%Light media (under 500 KB) 14%92%

WordPress 2,342 sitesNo audio/video media 85%Light media (under 500 KB) 11%66%

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, 89% of sites with under 500 KB of audio/video media audio and video payload have a good LCP, against 93% of Wix sites with no audio or video requests. Within Wix, sites with under 500 KB of audio/video media and no audio or video requests have a good LCP about equally often. On WordPress, 65% of sites with under 500 KB of audio/video media audio and video payload have a good LCP, against 66% of WordPress sites with no audio or video requests. Within WordPress, sites with under 500 KB of audio/video media and no audio or video requests have a good LCP about equally often.

On Wix, 100% of sites with under 500 KB of audio/video media audio and video payload have a good INP, against 100% of Wix sites with no audio or video requests. Within Wix, sites with under 500 KB of audio/video media and no audio or video requests have a good INP about equally often. On WordPress, 100% of sites with under 500 KB of audio/video media audio and video payload have a good INP, against 99% of WordPress sites with no audio or video requests. Within WordPress, sites with under 500 KB of audio/video media and no audio or video requests 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, 78% pass field LCP at a 1.5s median, versus 80% (1.6s median) under 500 KB and 83% (1.4s median) above 3 MB.