MPEG-4/H.264 video format

- OTHER

Commonly used video compression format.

IE

  1. 5.5 - 8
  2. 9 - 10
  3. 11

Edge

  1. 12 - 81
  2. 83

Firefox

  1. 2 - 20
  2. 21 - 34
  3. 35 - 75
  4. 76
  5. 77 - 78

Chrome

  1. 4 - 81
  2. 83
  3. 84 - 86

Safari

  1. 3.1
  2. 3.2 - 13
  3. 13.1
  4. TP

Opera

  1. 9 - 24
  2. 25 - 67
  3. 68

iOS Safari

  1. 3.2 - 13.3
  2. 13.4

Opera Mini

  1. all

Android Browser

  1. 2.1 - 2.2
  2. 2.3
  3. 3 - 4.3
  4. 4.4 - 4.4.4
  5. 81

Blackberry Browser

  1. 7
  2. 10

Opera Mobile

  1. 10
  2. 11 - 12.1
  3. 46

Chrome for Android

  1. 81

Firefox for Android

  1. 68

IE Mobile

  1. 10
  2. 11

UC Browser for Android

  1. 12.12

Samsung Internet

  1. 4 - 10.1
  2. 11.1

QQ Browser

  1. 10.4

Baidu Browser

  1. 7.12

KaiOS Browser

  1. 2.5

Firefox supports H.264 on Windows 7 and later since version 21. Firefox supports H.264 on Linux since version 26 if the appropriate gstreamer plug-ins are installed.

Partial support for older Firefox versions refers to the lack of support in OS X & some non-Android Linux platforms.

Resources:
Firefox extension allowing support in Win7
Wikipedia article