Compatibility/Telemetry

Measuring web compatibility

This page tracks the telemetry measurements that the Web Compat team is tracking. See Telemetry for more information.

Bug 1109958 will serve as the meta tracking bug for all telemetry probes.

Possible telemetry probes

CSS

• `display: table` with `max-width: 100%` on children.

HTTP

• WAP (WML or XHTMLMP) content sent to Fennec users
• `Server:` name
• Redirection sequences
• Wrong mimetypes for images
• Wrong mimetypes for JSON

JS/DOM

• (When Possible) identify the js lib used against a DB of the latest versions of JS libs. (to understand the use of legacy code)
• Identify, count how many times `navigator.userAgent` is used on the Web and a couple of other related thing.
• WebKitCSSMatrix usage See https://bugzilla.mozilla.org/show_bug.cgi?id=717722

Video

• M3U8 src for <video>
• requestFullScreen vs requestFullscreen. See https://bugzilla.mozilla.org/show_bug.cgi?id=743198#c5
• format (ogg, mp4, h264, etc.)
• Ads before video and transition to video
• EME required
• geofencing for IP rights
• List of video providers (stats for understanding if we need to focus our contacts actions toward some specific people)
• List of JS libraries used for video players
• H.264 AVC profile info
• Flash-only video
• Media MIME types
  • HTMLMediaElement.canPlayType()
  • MediaSource.isSupportedType()
  • MediaSource.addSourceBuffer(DOMString type)
• Video dimensions
• Compressed video sample sizes
• Frame drops
• Hardware or software decoders
• Playing videos concurrently
• H.264 profile/flags/level
• Audio speaker configuration e.g. mono, stereo, 5.1
• "How many videos have the FRext bit set in the SPS" (req from Andreas Gal)

Related information

h264 rec: http://www.itu.int/rec/T-REC-H.264-201402-I/en