--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -125,16 +125,20 @@ MediaLoadUnsupportedMimeType=HTTP “Content-Type” of “%1$S” is not supported. Load of media resource %2$S failed.
 # LOCALIZATION NOTE: %S is the URL of the media resource which failed to load because of error in decoding.
 MediaLoadDecodeError=Media resource %S could not be decoded.
 MediaWidevineNoWMF=Trying to play Widevine with no Windows Media Foundation. See https://support.mozilla.org/kb/fix-video-audio-problems-firefox-windows
 # LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
 MediaWMFNeeded=To play video formats %S, you need to install extra Microsoft software, see https://support.mozilla.org/kb/fix-video-audio-problems-firefox-windows
 # LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
 MediaPlatformDecoderNotFound=The video on this page can’t be played. Your system may not have the required video codecs for: %S
 MediaUnsupportedLibavcodec=The video on this page can’t be played. Your system has an unsupported version of libavcodec
+# LOCALIZATION NOTE: %1$S is the URL of the media resource, %2$S is technical information (in English)
+MediaDecodeError=Media resource %1$S could not be decoded, error: %2$S
+# LOCALIZATION NOTE: %1$S is the URL of the media resource, %2$S is technical information (in English)
+MediaDecodeWarning=Media resource %1$S could be decoded, but with error: %2$S
 # LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
 MediaCannotPlayNoDecoders=Cannot play media. No decoders for requested formats: %S
 # LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
 MediaNoDecoders=No decoders for some of the requested formats: %S
 MediaCannotInitializePulseAudio=Unable to use PulseAudio
 # LOCALIZATION NOTE: Do not translate "MediaRecorder".
 MediaRecorderMultiTracksNotSupported=MediaRecorder does not support recording multiple tracks of the same type at this time.
 # LOCALIZATION NOTE: %S is the ID of the MediaStreamTrack passed to MediaStream.addTrack(). Do not translate "MediaStreamTrack" and "AudioChannel".