diff --git a/toolkit/components/antitracking/test/browser/browser_staticPartition_cache.js b/toolkit/components/antitracking/test/browser/browser_staticPartition_cache.js
index 9afe3180fba8..9383e5a6f9fb 100644
--- a/toolkit/components/antitracking/test/browser/browser_staticPartition_cache.js
+++ b/toolkit/components/antitracking/test/browser/browser_staticPartition_cache.js
@@ -105,7 +105,7 @@ add_task(async function () {
// The CSS cache needs to be cleared in-process.
content.windowUtils.clearSharedStyleSheetCache();
- let videoURL = arg.urlPrefix + "file_thirdPartyChild.video.ogv";
+ let videoURL = arg.urlPrefix + "file_thirdPartyChild.video.webm";
let audioURL = arg.urlPrefix + "file_thirdPartyChild.audio.ogg";
let URLSuffix = "?r=" + arg.randomSuffix;
@@ -176,7 +176,7 @@ add_task(async function () {
"xhr.html",
"worker.xhr.html",
"audio.ogg",
- "video.ogv",
+ "video.webm",
"fetch.html",
"worker.fetch.html",
"request.html",
diff --git a/toolkit/components/antitracking/test/browser/file_saveAsPageInfo.html b/toolkit/components/antitracking/test/browser/file_saveAsPageInfo.html
index 8f22e911e723..e74e18695e4d 100644
--- a/toolkit/components/antitracking/test/browser/file_saveAsPageInfo.html
+++ b/toolkit/components/antitracking/test/browser/file_saveAsPageInfo.html
@@ -1,6 +1,6 @@
-
+
diff --git a/toolkit/components/antitracking/test/browser/file_video.ogv b/toolkit/components/antitracking/test/browser/file_video.ogv
deleted file mode 100644
index 68dee3cf2b1d..000000000000
Binary files a/toolkit/components/antitracking/test/browser/file_video.ogv and /dev/null differ
diff --git a/toolkit/components/antitracking/test/browser/file_video.webm b/toolkit/components/antitracking/test/browser/file_video.webm
new file mode 100644
index 000000000000..2cee5a9e51e8
Binary files /dev/null and b/toolkit/components/antitracking/test/browser/file_video.webm differ
diff --git a/toolkit/components/windowcreator/test/320x240.ogv b/toolkit/components/windowcreator/test/320x240.ogv
deleted file mode 100644
index 093158432ac6..000000000000
Binary files a/toolkit/components/windowcreator/test/320x240.ogv and /dev/null differ
diff --git a/toolkit/components/windowcreator/test/320x240.webm b/toolkit/components/windowcreator/test/320x240.webm
new file mode 100644
index 000000000000..16ecdbf688bd
Binary files /dev/null and b/toolkit/components/windowcreator/test/320x240.webm differ
diff --git a/toolkit/components/windowcreator/test/bug449141_page.html b/toolkit/components/windowcreator/test/bug449141_page.html
index 3b8e3f550ac4..4c8e46dd10b4 100644
--- a/toolkit/components/windowcreator/test/bug449141_page.html
+++ b/toolkit/components/windowcreator/test/bug449141_page.html
@@ -6,6 +6,6 @@
-
+