diff --git a/phpBB/includes/acp/acp_attachments.php b/phpBB/includes/acp/acp_attachments.php
index f2d42aef1a..ebfff442a2 100644
--- a/phpBB/includes/acp/acp_attachments.php
+++ b/phpBB/includes/acp/acp_attachments.php
@@ -637,6 +637,7 @@ class acp_attachments
 					ATTACHMENT_CATEGORY_NONE		=> $user->lang['NO_FILE_CAT'],
 					ATTACHMENT_CATEGORY_IMAGE		=> $user->lang['CAT_IMAGES'],
 					ATTACHMENT_CATEGORY_AUDIO		=> $user->lang('CAT_AUDIO_FILES'),
+					ATTACHMENT_CATEGORY_VIDEO		=> $user->lang('CAT_VIDEO_FILES'),
 				);
 
 				$group_id = $request->variable('g', 0);
@@ -1412,6 +1413,7 @@ class acp_attachments
 			ATTACHMENT_CATEGORY_NONE		=> $user->lang['NO_FILE_CAT'],
 			ATTACHMENT_CATEGORY_IMAGE		=> $user->lang['CAT_IMAGES'],
 			ATTACHMENT_CATEGORY_AUDIO		=> $user->lang('CAT_AUDIO_FILES'),
+			ATTACHMENT_CATEGORY_VIDEO		=> $user->lang('CAT_VIDEO_FILES'),
 		);
 
 		if ($group_id)
diff --git a/phpBB/includes/constants.php b/phpBB/includes/constants.php
index 046cbf063b..286a9f2442 100644
--- a/phpBB/includes/constants.php
+++ b/phpBB/includes/constants.php
@@ -162,6 +162,7 @@ define('ATTACHMENT_CATEGORY_NONE', 0);
 define('ATTACHMENT_CATEGORY_IMAGE', 1); // Inline Images
 define('ATTACHMENT_CATEGORY_THUMB', 4); // Not used within the database, only while displaying posts
 define('ATTACHMENT_CATEGORY_AUDIO', 7); // Browser-playable audio files
+define('ATTACHMENT_CATEGORY_VIDEO', 8); // Browser-playable video files
 
 // BBCode UID length
 define('BBCODE_UID_LEN', 8);
diff --git a/phpBB/includes/functions_content.php b/phpBB/includes/functions_content.php
index f61c7928f8..4dd6fef47e 100644
--- a/phpBB/includes/functions_content.php
+++ b/phpBB/includes/functions_content.php
@@ -1323,6 +1323,15 @@ function parse_attachments($forum_id, &$message, &$attachments, &$update_count_a
 					$update_count_ary[] = $attachment['attach_id'];
 				break;
 
+				// Audio files
+				case ATTACHMENT_CATEGORY_VIDEO:
+					$block_array += [
+						'S_VIDEO_FILE'			=> true,
+					];
+
+					$update_count_ary[] = $attachment['attach_id'];
+				break;
+
 				default:
 					$l_downloaded_viewed = 'DOWNLOAD_COUNTS';
 
diff --git a/phpBB/install/schemas/schema_data.sql b/phpBB/install/schemas/schema_data.sql
index c3a3ff9876..d708a0d6ad 100644
--- a/phpBB/install/schemas/schema_data.sql
+++ b/phpBB/install/schemas/schema_data.sql
@@ -777,6 +777,7 @@ INSERT INTO phpbb_extension_groups (group_name, cat_id, allow_group, upload_icon
 INSERT INTO phpbb_extension_groups (group_name, cat_id, allow_group, upload_icon, max_filesize, allowed_forums) VALUES ('DOCUMENTS', 0, 0, '', 0, '');
 INSERT INTO phpbb_extension_groups (group_name, cat_id, allow_group, upload_icon, max_filesize, allowed_forums) VALUES ('DOWNLOADABLE_FILES', 0, 0, '', 0, '');
 INSERT INTO phpbb_extension_groups (group_name, cat_id, allow_group, upload_icon, max_filesize, allowed_forums) VALUES ('AUDIO_FILES', 7, 0, '', 0, '');
+INSERT INTO phpbb_extension_groups (group_name, cat_id, allow_group, upload_icon, max_filesize, allowed_forums) VALUES ('VIDEO_FILES', 8, 0, '', 0, '');
 
 # -- extensions
 INSERT INTO phpbb_extensions (group_id, extension) VALUES (1, 'gif');
@@ -842,6 +843,11 @@ INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'm4a');
 INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'ogg');
 INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'webm');
 
+INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'mp4');
+INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'ogg');
+INSERT INTO phpbb_extensions (group_id, extension) VALUES (6, 'webm');
+
+
 # Add default profile fields
 INSERT INTO phpbb_profile_fields (field_name, field_type, field_ident, field_length, field_minlen, field_maxlen, field_novalue, field_default_value, field_validation, field_required, field_show_novalue, field_show_on_reg, field_show_on_pm, field_show_on_vt, field_show_on_ml, field_show_profile, field_hide, field_no_view, field_active, field_order, field_is_contact, field_contact_desc, field_contact_url) VALUES ('phpbb_location', 'profilefields.type.string', 'phpbb_location', '20', '2', '100', '', '', '.*', 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, '', '');
 INSERT INTO phpbb_profile_fields (field_name, field_type, field_ident, field_length, field_minlen, field_maxlen, field_novalue, field_default_value, field_validation, field_required, field_show_novalue, field_show_on_reg, field_show_on_pm, field_show_on_vt, field_show_on_ml, field_show_profile, field_hide, field_no_view, field_active, field_order, field_is_contact, field_contact_desc, field_contact_url) VALUES ('phpbb_website', 'profilefields.type.url', 'phpbb_website', '40', '12', '255', '', '', '', 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 2, 1, 'VISIT_WEBSITE', '%s');
diff --git a/phpBB/language/en/acp/attachments.php b/phpBB/language/en/acp/attachments.php
index 4139f4f8b6..3c8ae0b340 100644
--- a/phpBB/language/en/acp/attachments.php
+++ b/phpBB/language/en/acp/attachments.php
@@ -69,6 +69,7 @@ $lang = array_merge($lang, array(
 	'ATTACH_TO_POST'					=> 'Attach file to post',
 
 	'CAT_AUDIO_FILES'			=> 'Audio files',
+	'CAT_VIDEO_FILES'			=> 'Video files',
 	'CAT_IMAGES'				=> 'Images',
 	'CHECK_CONTENT'				=> 'Check attachment files',
 	'CHECK_CONTENT_EXPLAIN'		=> 'Some browsers can be tricked to assume an incorrect mimetype for uploaded files. This option ensures that such files likely to cause this are rejected.',
diff --git a/phpBB/phpbb/db/migration/data/v400/add_video_files_attachment_group.php b/phpBB/phpbb/db/migration/data/v400/add_video_files_attachment_group.php
new file mode 100644
index 0000000000..cca0b244a8
--- /dev/null
+++ b/phpBB/phpbb/db/migration/data/v400/add_video_files_attachment_group.php
@@ -0,0 +1,86 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\db\migration\data\v400;
+
+class add_video_files_attachment_group extends \phpbb\db\migration\migration
+{
+	public static function depends_on()
+	{
+		return ['\phpbb\db\migration\data\v400\dev'];
+	}
+
+	public function update_data()
+	{
+		return [
+			['custom', [[$this, 'add_video_files']]],
+		];
+	}
+
+	public function add_video_files()
+	{
+		$sql = 'SELECT group_id
+			FROM ' . $this->table_prefix . 'extension_groups
+			WHERE ' . $this->db->sql_build_array('SELECT', ['group_name' => 'VIDEO_FILES']);
+		$result = $this->db->sql_query($sql);
+		$video_group_id = $this->db->sql_fetchfield('group_id');
+		$this->db->sql_freeresult($result);
+
+		if ($video_group_id === false)
+		{
+			$sql = 'INSERT INTO ' . $this->table_prefix . 'extension_groups ' . $this->db->sql_build_array('INSERT', [
+				'group_name'		=> 'VIDEO_FILES',
+				'cat_id'			=> ATTACHMENT_CATEGORY_VIDEO,
+				'allow_group'		=> 0,
+				'upload_icon'		=> '',
+				'max_filesize'		=> 0,
+				'allowed_forums'	=> '',
+			]);
+			$this->db->sql_query($sql);
+			$video_group_id = $this->db->sql_nextid();
+		}
+		else
+		{
+			$sql = 'UPDATE ' . $this->table_prefix . 'extension_groups SET cat_id = ' . ATTACHMENT_CATEGORY_VIDEO . '
+				WHERE ' . $this->db->sql_build_array('SELECT', ['group_id' => $video_group_id]);
+			$this->db->sql_query($sql);
+		}
+
+		$video_extensions = ['mp4', 'ogg', 'webm'];
+
+		foreach ($video_extensions as $video_extension)
+		{
+			$sql = 'SELECT group_id
+				FROM ' . $this->table_prefix . 'extensions
+				WHERE ' . $this->db->sql_build_array('SELECT', ['extension' => $video_extension]);
+			$result = $this->db->sql_query($sql);
+			$extension_group_id = $this->db->sql_fetchfield('group_id');
+			$this->db->sql_freeresult($result);
+
+			if ($extension_group_id === false)
+			{
+				$sql = 'INSERT INTO ' . $this->table_prefix . 'extensions ' . $this->db->sql_build_array('INSERT', [
+					'group_id'	=> $video_group_id,
+					'extension'	=> $video_extension,
+				]);
+				$this->db->sql_query($sql);
+			}
+			else if ($extension_group_id != $video_group_id)
+			{
+				$sql = 'UPDATE ' . $this->table_prefix . "extensions SET group_id = $video_group_id
+					WHERE " . $this->db->sql_build_array('SELECT', ['extension' => $video_extension]);
+				$this->db->sql_query($sql);
+			}
+		}
+	}
+}
diff --git a/phpBB/phpbb/mimetype/extension_guesser.php b/phpBB/phpbb/mimetype/extension_guesser.php
index 19de618df6..67a9d26e35 100644
--- a/phpBB/phpbb/mimetype/extension_guesser.php
+++ b/phpBB/phpbb/mimetype/extension_guesser.php
@@ -253,6 +253,7 @@ class extension_guesser extends guesser_base
 		'omc'		=> 'application/x-omc',
 		'oga'		=> 'audio/ogg',
 		'ogg'		=> 'audio/ogg',
+		'ogg'		=> 'video/ogg',
 		'ogm'		=> 'video/ogg',
 		'omcd'		=> 'application/x-omcdatamaker',
 		'omcr'		=> 'application/x-omcregerator',
@@ -426,6 +427,7 @@ class extension_guesser extends guesser_base
 		'wbmp'		=> 'image/vnd.wap.wbmp',
 		'web'		=> 'application/vnd.xara',
 		'webm'		=> 'audio/webm',
+		'webm'		=> 'video/webm',
 		'wiz'		=> 'application/msword',
 		'wk1'		=> 'application/x-123',
 		'wmf'		=> 'windows/metafile',
diff --git a/phpBB/phpbb/storage/controller/attachment.php b/phpBB/phpbb/storage/controller/attachment.php
index 7c3d355ad8..8df2727ea1 100644
--- a/phpBB/phpbb/storage/controller/attachment.php
+++ b/phpBB/phpbb/storage/controller/attachment.php
@@ -254,7 +254,8 @@ class attachment extends controller
 		$response->headers->set('Content-Type', $attachment['mimetype']);
 
 		// Display images in browser and force download for other file types
-		if (strpos($attachment['mimetype'], 'image') !== false || strpos($attachment['mimetype'], 'audio') !== false)
+		if (strpos($attachment['mimetype'], 'image') !== false || strpos($attachment['mimetype'], 'audio') !== false || 
+		strpos($attachment['mimetype'], 'video') !== false)
 		{
 			$disposition = $response->headers->makeDisposition(
 				ResponseHeaderBag::DISPOSITION_INLINE,
diff --git a/phpBB/styles/prosilver/template/attachment.html b/phpBB/styles/prosilver/template/attachment.html
index ceeea21d24..7d47ec13d0 100644
--- a/phpBB/styles/prosilver/template/attachment.html
+++ b/phpBB/styles/prosilver/template/attachment.html
@@ -49,6 +49,26 @@
 			</dl>
 		{% endif %}
 
+		{% if _file.S_VIDEO_FILE %}
+			<dl class="file">
+				<dt class="c-file-header">
+					<video class="c-file-video-controls" controls="controls" preload="metadata">
+						<source class="c-file-video-source" src="{{ _file.U_DOWNLOAD_LINK }}" type="{{ _file.MIMETYPE }}">
+					</video>
+				</dt>
+				{% if _file.COMMENT %}
+					<dd class="c-file-comment">{{ _file.COMMENT }}</dd>
+				{% endif %}
+				<dd class="c-file-actions">
+					{% if _file.UPLOAD_ICON %}
+						<span class="o-icon c-file-icon">{{ _file.UPLOAD_ICON }}</span>
+					{% endif %}
+					<a class="c-file-actions-link postlink" href="{{ _file.U_DOWNLOAD_LINK }}" download>{{ _file.DOWNLOAD_NAME }}</a>
+					<span class="c-file-actions-meta">({{ _file.FILESIZE }} {{ _file.SIZE_LANG }}) {{ _file.L_DOWNLOAD_COUNT }}</span>
+				</dd>
+			</dl>
+		{% endif %}
+
 		<!-- EVENT attachment_file_append -->
 	<!-- ENDIF -->
 <!-- END _file -->
diff --git a/phpBB/styles/prosilver/theme/content.css b/phpBB/styles/prosilver/theme/content.css
index 04dd1f38e5..2296a15224 100644
--- a/phpBB/styles/prosilver/theme/content.css
+++ b/phpBB/styles/prosilver/theme/content.css
@@ -688,6 +688,16 @@ dl.thumbnail dt a:hover img {
 	max-width: 100%;
 }
 
+.c-file-audio-source {
+}
+
+.c-file-video-controls {
+	max-width: 100%;
+}
+
+.c-file-video-source {
+}
+
 /* Post poll styles
 ---------------------------------------- */
 fieldset.polls {