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Specification for Apps 2022

Version: 4.22

Date: 2021-12-28



Version Number







Publication release





  • Removed text about terminal-defined behavior in the exit key. The application may now manage this key event freely.
  • The Application MUST handle both VK_BACK_SPACE and VK_BACK.
  • The Application MUST support HD, Full HD or both resolutions
  • Removed mention of viewport META tag
  • The Application MUST explicitly set colors
  • Restructured content
  • Improved clarity and grammar




Publication release


  • Rebranded to a new company entity


  • Updated Chromium version
  • Fixed MSE reference [30]
  • Added sections on HDR and 4K video support


  • Removed VP8 support
  • Added AV1 as an optionally available codec for MSE
  • Added Ogg Vorbis audio codec support
  • Added Dolby AC4 codec
  • Added Marlin DRM support
  • Stricter rules for Widevine support
  • Optional feature "persistent licenses" for Widevine is removed
  • Added CMAF multimedia format section
  • Changed reference links
  • Added requirement for PlayReady automatic license acquisition
  • Added restrictions to adaptive streaming content
  • Added CBCS support for PlayReady and Widevine DRM




  • No changes in requirements.




  • Added AV1 codec support in MPEG-DASH streaming protocol requirement


2.1 Scope

This document specifies the requirements for Vewd TV Applications and provides guidelines on how to develop Vewd-compliant apps. It is primarily aimed at app developers and owners.

This document is closely connected to the Specification for Devices [1] which defines the platform that Vewd TV Applications run on.

2.2 Abstract

To have an app certified for Vewd, the owner or developer must submit it for review. This document defines the requirements and criteria for certification and also gives guidelines for developers on how to make apps function well on devices integrating the Vewd Core.

While applications may use any available web technologies outside these specifications to provide an enhanced experience for devices with a richer feature set, the application must provide graceful fallbacks outlined within these specifications to provide the same basic functionality to all Vewd Devices.

2.3 Definitions

Chromium and Google Chrome - Chromium is the open-source project that forms the basis for the Google Chrome browser.

Vewd Core - An embeddable browser and streaming engine with an extensible API, based on the Chromium open-source project, which implements a set of international and industry standards to download and render webpages, execute web apps, and stream video and audio content.

Vewd TV Application - A web app that is Vewd-compliant and is certified to run on Vewd Devices.

Also referred to as App or Application in this document.

Vewd Device - A TV or STB device running software based on the Vewd Core, and certified to meet the requirements defined in the Vewd Device Specification [1].

Vewd Specification for Devices - Specifies platform requirements that a Vewd Device must meet to be officially certified, and, therefore specifies the platform that an app can expect when running on a Vewd Device.


2.4 Compliance terminology used in this document

The following keywords used in this specification to indicate the level of compliance needed for the requirements are sourced from RFC2119. In essence:

  • MUST, REQUIRE or SHALL indicates that you need to comply with the requirement absolutely.
  • SHOULD or RECOMMENDED indicates that while sometimes there could be valid reasons to ignore the requirement, you need to fully understand and accept the implications and risks to optimal end-user experience.
  • MAY or OPTIONAL indicates that you can decide to implement an item at your discretion.

We also use an additional compliance term not described in RFC2119:

  • CONDITIONALLY REQUIRED - an item or a feature is supported in the browser if the underlying platform supports this capability.

2.5 Changes and Versioning

When the Specification for Apps or the Specification for Devices [1] are changed, the version number of both documents will be updated to match the corresponding Vewd Core version.

2.5.1 Backward compatibility

New versions of these requirements may not be backward compatible with previous versions. Web standards and technologies are evolving fast; some older specifications may be replaced with more modern features, and their support may be removed. The deprecation process is relatively slow, but cannot be totally avoided. This specification and the Specification for Devices list features that were deprecated since the previous version and also mark features that might be deprecated in later versions. You should be careful if using features marked for possible deprecation.

2.5.2. Specification and Software Versions

The Application Requirements document defines compliance requirements for a particular version of the Specification for Devices[1], Vewd Core, and Chromium. The table below defines corresponding versions:

Specification for Devices version

Vewd Core

Google Chromium


4.10.0 LTS










This section outlines the requirements for an app to be certified to run on Vewd TV  Devices.

3.1 Browser engine

A Vewd TV Application runs in a browser engine based on Chromium so almost all Chromium features and Chromium-supported web standards are available to app developers. However, a TV is a limited device, normally without a keyboard, mouse, or touch-screen support, and without a desktop user interface. A typical TV also has a greater screen size, runs apps in fullscreen, and is designed to be viewed at a distance, while having a slower CPU and less memory (RAM) than a typical PC, tablet, or mobile phone.

3.1.1 User Agent string

Apps should test for the presence of specific features whenever possible, and SHOULD NOT associate specific User Agent strings with device feature sets. For more information, refer to the Specification for Devices [1] section 4.8. “User Agent String”.

If the app should be loaded through the Vewd App Store, it can search for the string “TV Store” in the UserAgent string.

3.2 Standards compliance

3.2.1. Web specifications

Due to the nature of TV devices, not all features available in desktop and mobile browsers are supported.

Apps MUST NOT rely on the following browser features; they are not supported by Vewd Devices. Note that this list is not exhaustive or exact, but aims to highlight some important exclusions. There may be other features that are unavailable or have limited functionality compared to a desktop or mobile browser.

  • Adobe Flash
  • Audio Output Device API [14]
  • Device Orientation [4]
  • Downloaded Plugins (including NPAPI and PPAPI)
  • Drag and Drop Directories [5]
  • Extensions
  • FTP
  • Geolocation [6]
  • High Resolution Timestamp [15]
  • JavaScript dialogs
  • Password manager
  • Pointer Events [7]
  • Touch Events [10]
  • Vibration API [8]
  • Web Audio [13]
  • Web Notifications [9]
  • Web Speech API [12]
  • WebRTC [11]

To assess web standards compliance and the availability of a particular feature you can check these online resources:

Look for the Chrome (Chromium) version in the Specification and Software versions above.

3.2.2 HbbTV, CE-HTML and OIPF

Apps MUST NOT rely on HbbTV [16] and OIPF [18] standards and related profiles (Freeview Play, TDT Híbrida, TNT2). Support for these standards is out of the scope of this specification, even though the Vewd Core itself supports these standards.

Apps MUST NOT rely on the CE-HTML video object defined in CEA-2014 [17] since it is not necessarily supported by Vewd Devices.

3.2.3 WebGL

Apps MUST NOT rely on the WebGL [19] standard. It is not a mandatory requirement for Vewd Devices so it will not be available on all devices.

This is normally supported on high-end devices, but typically requires more platform resources than CSS/HTML/JavaScript.

The app can detect the availability of WebGL as follows:

if (!window.WebGLRenderingContext) {
    console.log("WebGL is not supported by browser");
} else {
    var canvas = document.createElement("canvas");
    var context = canvas.getContext("webgl");
    if (!context) {
        console.log("WebGL is supported by browser but disabled");
    } else {
        console.log("WebGL is supported by browser and enabled");

3.3 Media streaming and DRM

This section highlights the supported streaming and DRM protocols by Vewd Devices. See Annex C: Supported media by HTML5 MediaElement for a complete table.

3.3.1 Progressive downloads

Progressive download of video and audio is supported by Vewd Devices, but note that:

  • Protected content (DRM) is not supported with progressive download
  • In-band subtitles are not supported with progressive download
  • Out-of-band subtitles are supported with any streaming or download as they are handled outside of the media streaming

Apps MAY rely on support for the following combinations on Vewd Devices:


Audio codec

Video codecs






Dolby AC3

Dolby E-AC-3










Dolby AC3

Dolby E-AC-3













3.3.2 Adaptive Bitrate protocols

Apps MAY rely on support for the following Adaptive Bitrate Streaming (ABR) protocols:

Streaming Type



Apple HTTP Live Streaming (HLS)



VoD (static playlists) and Live (dynamic playlists)



Main profile and Live profile of MPEG-DASH

Microsoft Smooth Streaming (MSS)


application/ Restrictions for HLS content

  1. Audio/video encoding

    1. The same codec MUST be used across all variant streams (all quality levels).

    2. Audio parameters (number of channels and sample rates) MUST be the same across all variant streams.

  2. Media segments

    1. All media segments MUST be independently decodable. Consequently, the first video frame in every segment that contains video MUST be an IDR frame.

    2. Discontinuities in timestamps, frame rate, encoding profiles, or audio/video parameters MUST NOT occur within segments.

  3. Playlist files (M3U8)

    1. Audio and video playlists MUST use the same target duration and MUST contain the same duration of the content.

    2. A playlist MUST NOT contain invalid URLs.

    3. Media sequence numbers MUST be aligned across all variant streams (quality levels), so that media sequence numbers can be used to identify matching content.

    4. For live streams, media segments MUST remain available on the server for at least one target duration after the segment disappears from the playlist.

    5. Playlists MUST use sufficiently accurate segment durations to ensure that the sum of the #EXTINF durations of any contiguous group of segments is within one video frame duration of the actual duration.

    6. Playlists MUST provide at least 6 segments in live/linear streams.

    7. Discontinuities in timestamps, frame rate, encoding profiles, or audio/video parameters MAY occur between segments, but such discontinuities MUST be indicated using the #EXT-X-DISCONTINUITY tag.

    8. EXT-X-STREAM-INF tags MUST always provide CODECS and RESOLUTION attributes.

  4. Subtitles

    1. The app MUST support subtitles that conform to the Subtitles and Closed Captions section.

  5. DRM

    1. The decryption key MUST be directly downloadable via an HTTP or HTTPS URLs

    2. Note that with AES-128 encrypted HLS, segments are completely encrypted. Restrictions for MPEG-DASH content

  • The media segment container format MUST be the ISO Base Media File Format (aka MP4).

  • All media segments MUST be independently decodable. Consequently, the first video frame in every segment that contains video MUST be an IDR frame.

  • Manifest URLs MAY include the MPD anchor, but MUST NOT use any other than the ‘t’ parameter ([3] section C.4)

  • The app MAY support multiple audio tracks associated with multiple Adaptation Sets defined in an MPD of MPEG-DASH.

  • Each audio track MUST be a separate media stream.

  • Support for the <SegmentList> element is NOT REQUIRED.

  • The app MAY support multiple Periods defined in an MPD of MPEG-DASH. Restrictions for MSS content

  • All media segments MUST be independently decodable. Consequently, the first video frame in every segment that contains video MUST be an IDR frame.

  • For live streams that use FragmentLookahead, segments MUST remain available on the server for one DVRWindowLength after they disappear from the Manifest file.

3.3.3 Media Source Extensions (MSE)

Apps MAY rely on Media Source Extensions to be supported according to the MSE specification [30]For information about container and codec support, please see: Annex C: Supported media by HTML5 MediaElement. 

3.3.4 Subtitles & Closed captioning

Apps MAY rely on support for in-band and out-of-band subtitles (text tracks) according to the table below:

Media delivery method

In-band Subtitles

Out-of-band Subtitles

Progressive playback

Not supported



Not supported





Smooth Streaming




Not supported


3.3.5 DRM

Apps MAY rely on support for the following DRM technologies: Annex A: DRM code Examples. ClearKey

  • Supported with EME PlayReady

  • Supported with EME
  • Supported with WebInitiator
  • PlayReady Header Object v4.0.0.0 is supported
  • PlayReady Header Object v4.1.0.0 may be supported
  • Supported for security level "2000"
  • If supported, supported with security level "3000" on devices supporting Ultra HD/4K (2160p) resolution

For an example of implementing PlayReady with WebInitiator, see: 6.1 Playready License Acquisition

  • The app MAY rely on automatic license acquisition, supporting the following:
    • License Acquisition URLs provided in the manifest
    • License Acquisition URL provided in the WebInitiator Widevine

  • Supported if the platform has Widevine DRM installed
  • If supported, supported with EME
  • If supported, supported with security level “L2”
  • If supported, supported with security level “L1” on devices supporting Ultra HD/4K (2160p) resolution
  • MAY support "server certificate" and "privacy mode" features AES-128 encryption

  • Supported for Apple HLS streams
  • Supported for at least one of the following encryption algorithms:
    • AES 128 bit keys in CENC mode: Counter Mode (AES-CTR) and Full-Sample encryption
    • AES 128 bit keys in CBCS mode: Cipher Block Chaining mode (AES-CBC) and Sub-Sample encryption

For more information about Media streaming and DRM, refer to the Specification for Devices [1].

EME can only be used on secure contexts, it can not be used on any pages served over HTTP. App developers MUST use a secure origin (HTTPS).

3.3.6 4K video resolution

Apps MUST NOT rely on devices having support for 4K resolution. If the device does support 4K resolution, it will be available in Vewd. See the Specification for Devices [1] for more details.

3.3.7 CMAF multimedia format

Common Media Application Format (CMAF) [34] combines and constrains several MPEG specifications to define a multimedia format optimized for delivery of a single adaptive multimedia presentation to a variety of devices, using various adaptive streaming formats, broadcast, download, and storage methods. The device MUST support this standard.

For more information, refer to the Specification for Devices [1] section 3.6.4. “CMAF multimedia format”.

3.3.8 High Dynamic Range

Apps MUST NOT rely on devices having support for High Dynamic Range (HDR). If the devices do support HDR, it will be available in Vewd. See the Specification for Devices [1] for more details.

3.4 Performance

Performance requirements for Vewd TV Applications are significantly stricter than for web applications for PC or mobile. However, performance considerations, recommendations for enhancements, and optimization approaches are similar across devices and can be applied to all Vewd TV Applications.

It is important to understand that even high-end TV and STB devices have very limited computational, memory, and graphics resources. Even though new device models are refreshed and manufactured regularly, the aforementioned resources are unlikely to significantly improve on the previous year's models.

The average specification of a mid-range TV may look like the following:

  • Low-range CPU, often under 1GHz, dual-core ARM or MIPS architecture
  • Less or equal to 1GB of RAM
  • Low range GPU (e.g. Mali-400) with limited or no video memory
  • Large screen with Full HD (1920 x 1080, 2M pixels), or Ultra HD/4K (3840 x 2160, 8M pixels)

This makes TV devices much slower than an average PC. Note also that most of these resources are reserved for the platform, operating system, and browser engine, so there may be as little as 150MB out of 1GB available for the app.

3.4.1. Memory consumption

Apps SHOULD NOT use more than 150MB of memory.

Memory consumption affects app performance, and as mentioned above, the amount of memory available for apps is very limited on devices. In addition, TV devices typically have a hard memory limit so if an app uses a lot of memory, it could suffer from performance degradation or be killed.

You should be aware of the size of your DOM tree and prune away unnecessary nodes, as this can be a major factor of uncollected memory consumption.

3.4.2 Graphics requirements and animations

Apps SHOULD NOT use heavy graphics and complex animations.

Even though modern TV devices are now using specialized GPU chipsets, their graphics performance is usually still quite modest.

3.4.3 Hardware-accelerated features

Apps MAY NOT rely on CSS 3D transforms [27] or WebGL [19] features.

Unfortunately, not all TV devices support OpenGL ES 2.0 [28].

3.4.4 Performance acceptance criteria

Applications MUST meet the following performance requirements on Vewd Devices.

Vewd will reject applications that are unable to meet these performance requirements, based on tests run onVewd reference devices, and commercial devices currently in development. If your application is unable to meet them, Vewd will engage with you and attempt to help you reproduce performance issues on commercially available hardware and resolve them. Load time

The time between when the browser first starts loading the application, and when the application is loaded to the point where it is functional, MUST NOT exceed 30 seconds. Internal navigation

The time between when the user initiates internal navigation within the application, for instance navigating within a menu or selecting between different videos, and when the user is able to activate the new selection, MUST NOT exceed 1 second. Action latency

The time between when the user performs any kind of action on the application, and when the user receives feedback that the action has been initiated, MUST NOT exceed 4 seconds.

3.5 Security

3.5.1 Transport Layer Security (TLS)

You should always protect your apps with HTTPS, even if there is no sensitive communication. HTTPS provides critical security and data integrity both for the app and for users.

3.5.2 Same-Origin policy

Vewd Devices apply the Same-Origin policy as mentioned in section 4.10 "Security" in the Device Specification [1]. This is sometimes less permissive than other browser engines and previous Vewd Core versions, so apps may need to adapt if they are to be ported from such a platform. To prevent apps from breaking the Same-Origin policy, use Cross-Origin Resource Sharing (CORS) [20].

3.5.3 Mixed content

Apps MUST NOT use any kind of active mixed content (mixing secure and insecure requests). Insecure requests will be blocked by the browser engine as they are serious security vulnerabilities.

For information about the security aspects of mixed content and how to fix them, refer to the W3C specification, or articles on the internet, such as "Prevent mixed content" by Google [22] or "Mixed content" by Mozilla [23].

3.5.4 Pop-ups

Apps MUST NOT use any pop-up windows or dialogs. Pop-ups are blocked by Vewd Devices.

3.6 Input handling

3.6.1 Key mapping

Apps SHOULD NOT use numerical key codes directly.

Vewd Devices provides standardized keycodes as global JavaScript constants to use in apps, as the numerical value of key codes differs between devices (see the Device Specification, section 4.7. Input handling [1]).

Hardware key

JavaScript constant



Always present in remote controls


Always present in remote controls


Always present in remote controls


Always present in remote controls

Confirm / Select / OK


Always present in remote controls

Back / Return


Always present in remote controls

Back / Return


Always present in remote controls

Exit / Close ***

Usually present in remote controls*



Usually present in remote controls*



Usually present in remote controls*



Usually present in remote controls*



Usually present in remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*

FF (Fast-Forward)


Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*



Not available in some remote controls*

Not available in some remote controls and Usually present in remote controls * - not all devices have a corresponding physical key on the remote control and are conditionally required by the Device Specification [1].

VK_BACK_SPACE ** - handling this key code is important for compatibility with the Vewd App Store and older versions of the Vewd Core.

Exit / Close *** - this hardware key will be handled by the browser and can not be overridden by the application. Navigation and Select keys

The Navigation and Select keys are mandatory and result in sending corresponding key codes on key events into the app. If the navigation keys are not handled and prevented by the app, this MIGHT trigger automatic (spatial) navigation, but the result of this is undefined. Back key

The Back/Return button is a mandatory button on the remote control to go back or close the app.

The app MAY handle the Back/Return key event. If it does handle the Back/Return key, the app MUST handle both VK_BACK and VK_BACK_SPACE to ensure compatibility between legacy and current devices. On the remote control, the key may be marked with "Back", "Return" or similar. The Back/Return key SHOULD provide the user with typical back navigation, and finally, an exit path via window.close() to leave the app and return to the previous screen (for example, the Vewd App Store if the app was launched from there).

There are additional requirements for apps that are deployed in the Vewd App Store. For more details, refer to Functional Key Handling in Vewd App Store Applications [33]. Color keys

The blue, green, red, and yellow color keys are conditionally required on remote controls that have them, however, the placement and order of color keys will differ depending on device manufacturer and geographical region.

3.6.2 Virtual Keyboard

Apps MAY rely on the On-Screen Keyboard or Virtual Keyboard provided on Vewd Devices to allow the user to enter text. Do not make any assumptions about the visual appearance of this keyboard as this depends on the device make and model. Be aware that when activated, the Virtual Keyboard may be displayed over any portion of the screen, and can cover any part of the app. This sometimes leads to design inconsistencies.

If you want to change the look and feel of text inputs to match the particular design of your app, you MAY implement your own text input mechanism in JavaScript (for example, using a div marked a content editable instead of a text field).

Also, be aware that on some devices the Virtual Keyboard only supports a limited set of languages.

3.6.3 External input devices

Apps MUST NOT reply on the availability of external input devices such as a pointer remote, USB keyboard, and mouse, even though some Vewd Devices support these.

3.7 User interface and usability

3.7.1 TV screen size and resolution

Design apps for at least one of the following screen resolution configurations:

  1. HD resolution (1280 x 720)
  2. Full HD resolution (1920 x 1080)
  3. Both HD and Full HD resolutions can be supported by one application

Important notes:

Manufacturers do not set the physical screen size or pixel ratio in the firmware, so this information is not available for apps.
The media player may be able to play video in other resolutions than the resolution that the app is rendered in. Use the JavaScript canPlayType method on the HTML5 Video element to detect this.

3.7.2 Overscan

Be aware of possible overscan problems where margins of your app might be shown outside the visible area of the TV screen. As a general guide, assume that a 4% margin might not be visible to the user when designing your app. Test to ensure that the app works and displays correctly with margins applied for the visible areas.

This is because TV sets, even the most recent, large Ultra HD/4K models, may set a certain amount of overscan by default. The amount of overscan varies from manufacturer and model. While it is possible for users to turn off overscan, we recommend that you design your app with this invisible margin in mind as most users are likely unaware of this option.

3.7.3 Layout Text Size

Text size MUST be large enough to be seen on a TV screen from 3 meters (10 feet) away: the average distance that users sit from the TV.

The minimum text size RECOMMENDED for Vewd TV Applications is 3/100 of the screen height, or "3vh" in CSS (this gives approximately 32px at 1920 x 1080px):

p { font-size: 3vh; }

See Viewport-percentage lengths in CSS Values and Units Module Level 3 [24].

3.7.4 Colors

Apps MUST explicitly set colors for all visual elements including text and page background colors.

The app MUST not rely on any default colors defined by the browser engine.

* { background-color: #000000; color: #ffffff; }

Apps MUST NOT rely on platform-specific spatial navigation mechanisms and SHOULD instead provide navigation implemented by the app (e.g. in JavaScript).

3.7.5 Navigation

Spatial navigation SHOULD be explicitly blocked (by calling Event.preventDefault) if the app implements its own navigation mechanism.

For an example of implementing navigation with JavaScript, see Annex B: JavaScript navigation.

3.7.6 App exit

You SHOULD provide an explicit option or button in the UI to close the app with a simple call to the window.close() method.

This is because when an app is launched, it opens in a full screen in a new window on the TV, it runs completely “chromeless”, with no address bar or user interface controls. Users will be able to close the app and return to the main TV screen (or dashboard) via the remote control’s Exit/Close and/or Back/Return” keys (as mentioned above) but it’s a good idea to provide another, more explicit option.

3.7.7. Inputs and forms

Apps SHOULD NOT use input elements or forms as these don’t provide a good user experience on a TV, even though Vewd Devices support these elements and also provide a Virtual Keyboard (On-Screen Keyboard). This includes the use of <input> of all types, <textarea>, <form>, <fieldset>, <select>, <option>, <optgroup>, <datalist>, <keygen> elements.

3.7.8 Fonts

You SHOULD NOT rely on built-in fonts but instead use downloadable web fonts.

A Vewd Device provides Sans Serif fonts containing all the characters required to properly render the text in the languages available on the device, but the exact font used may vary among device models. Right-to-left text rendering is also supported if required by any language available on the device. However, the identity, look, and language coverage of these fonts cannot be guaranteed across all devices.

Consider the following when using web fonts:

  • Font resources MUST be in the WOFF [31] / WOFF2 [32] (Web Open Font Format) or TTF (TrueType Font) file format.
  • Font resources SHOULD NOT be large, otherwise they can take a long time to download and also consume a lot of memory and CPU power.
  • The Font Loading API [25] can be used to improve text rendering performance.

3.8 Data management

3.8.1 Temporary and persistent storage

Be aware that devices have very limited storage capacity. For more information, refer to the Device Specification [1], section 4.12.5. "Storage".

An app SHALL NOT rely on Persistent Storage Quota request when using the Quota Management API [26].

Chrome 'unlimitedStorage' permission is not available to Vewd TV Applications.

3.8.2 Cookies

An app MAY use up to 180 cookies per domain and each cookie will be available for a minimum of 30 days.

The maximum number of cookies stored in the Vewd Device database is set to 2000, each using a maximum of 4096 bytes. 

3.9 Supplementary multimedia devices

Apps MUST NOT rely on the microphone or camera being available on the device.



Application Programming Interface


Consumer Electronics Association standard 2014 [17]


Consumer Electronics Hyper Text Markup Language [17]


Cross-Origin Resource Sharing [20]


Central Processing Unit


Cascading Style Sheets


Document Object Model


Digital Rights Management


File Transfer Protocol


Hybrid Broadcast Broadband TV [16]


HTTP Live Streaming


Hyper Text Markup Language specification version 5


Hypertext Transfer Protocol


Hypertext Transfer Protocol Secure


International Organisation of Standardization


ISO Base Media File Format


MPEG-4 Part 14


Moving Picture Experts Group


MPEG2 Transport Stream


Media Source Extensions [30]


Microsoft Smooth Streaming


Netscape Plugin Application Programming Interface


Original Equipment Manufacturer


The Open IPTV Forum [18]


Pepper Plugin Application Programming Interface


Software Development Kit


Set-Top Box


TrueType Font


Web Graphics Library [19]


Web Open File Format [31]


WOFF File Format 2.0 [32]


[1]Vewd Device Specification

[2] “Can I Use” on-line service

[3] “Chrome Platform Status” on-line service

[4] DeviceOrientation Event Specification (W3C Editor's Draft 26 February 2016)

[5] WHATWG DragAndDropEntries

[6] Geolocation API Specification (W3C Recommendation 24 October 2013)

[7] Pointer Events (W3C Recommendation 24 February 2015)

[8] Vibration API (W3C Recommendation 10 February 2015)

[9] Web Notifications (W3C Recommendation 22 October 2015)

[10] Touch Events (W3C Recommendation 10 October 2013)

[11] WebRTC 1.0: Real-time Communication Between Browsers (W3C Working Draft 31 May 2016)

[12] Web Speech API Specification (W3C, 19 October 2012)

[13] Web Audio API (W3C Working Draft 08 December 2015)

[14] Audio Output Devices API (W3C Working Draft 01 June 2016)

[15] High Resolution Time Stamp for Events (Chrome Platform Status)

[16] HbbTV

[17] CE-HTML and CEA-2014

[18] Open IPTV Forum (OIPF) specifications

[19] WebGL Specification (Khronos Group, Version 1.0.3, 27 October 2014)

[20] Cross-Origin Resource Sharing (W3C Recommendation 16 January 2014)

[21] Mixed Content (W3C Candidate Recommendation, 08 October 2015)

[22] Prevent mixed content (Google Developers, Progressive Web App Dev Summit)

[23] Mixed content (Mozilla Development Network)

[24] CSS Values and Units Module Level 3 (W3C Candidate Recommendation, 11 June 2015)
Viewport-percentage lengths

[25] CSS Font Loading Module Level 3 (W3C Last Call Working Draft, 22 May 2014)

[26] Quota Management API (W3C Working Group Note 23 May 2016)

[27] CSS Transforms Module Level 1 (W3C Working Draft, 26 November 2013)

[28] OpenGL ES 2.0 (The Standard for Embedded Accelerated 3D Graphics)

[29] CSS Device Adaptation Module Level 1, Chapter 10: Viewport <META> element

[30] Media Source Extensions (W3C Candidate Recommendation 5 July 2016)

[31] WOFF File Format 1.0 (W3C Recommendation 13 December 2012)

[32] WOFF File Format 2.0 (W3C Candidate Recommendation 15 March 2016)

[33] Functional Key Handling in Vewd App Store Applications

 [34] ISO/IEC 23000-19:2018 Information technology — Multimedia application format (MPEG-A) — Part 19: Common media application format (CMAF) for segmented media

6. Annex A: DRM code Examples

6.1 PlayReady Web-Initiator license acquisition

Example of usage in HTML5 <video> tag.

    <source src="" type="application/" />

Example of PlayReady WebInitiator. <LicenseAcquisition> tag MUST contain <Content> tag, which is URL to MSS manifest.

<?xml version="1.0" encoding="utf-8"?>
<PlayReadyInitiator xmlns="">
        <Content>URL to MSS manifest</Content>
            <WRMHEADER xmlns= version="">
        <CustomData>Optional CustomData</CustomData>
Persistent licenses MAY be supported but web app MUST BE prepared to apply for the license again if the feature is not supported.

7. Annex B: JavaScript navigation

Example of handling navigation with JavaScript.

document.addEventListener("keydown", function(ev) {
    switch (ev.keyCode) {
        case VK_LEFT:
            // Handle mandatory key ←
        case VK_RIGHT:
            // Handle mandatory key →
        case VK_UP:
            // Handle mandatory key ↑
        case VK_DOWN:
            // Handle mandatory key ↓
        case VK_ENTER:
            // Handle mandatory key Confirm / Select / OK
        case VK_BACK:
        case VK_BACK_SPACE:
            // Handle mandatory key Back / Return
    // Block the browser from handling the keydown event.
}, false);

8. Annex C: Supported media by HTML5 MediaElement

Streaming TypeContainerAudio CodecVideo CodecDRMDRM TriggerInband subtitlesMime type
ProgressiveMP4 (ISO BMFF)AAC-LCH.264

H.265 *

AV1 *

Dolby AC3 *
Dolby E-AC-3 *
Dolby AC4 *
Dolby AC3 *
Dolby E-AC-3 *
Dolby AC4 *
WebM*Opus*VP9 *NoneNoneNonevideo/webm
ADTS / AACAAC-LCNoneNoneNoneNoneaudio/aac


Ogg *Vorbis *NoneNoneNoneNoneaudio/ogg
Adaptive (HLS)MPEG2-TSAAC-LCH.264H.265 *AES-128ManifestNoneapplication/
Dolby AC3 *
Dolby E-AC-3 *
Dolby AC4 *
Adaptive (DASH)MP4AAC-LCH.264H.265 *ClearKeyEMEEBU-TT-D
HE-AAC v1PlayReady
HE-AAC v2Widevine *
Dolby AC3 *
Dolby E-AC-3 *
Dolby AC4 *
Adaptive (MSS)PIFFAAC-LCH.264PlayReadyWeb InitiatorEBU-TT-D
HE-AAC v1PlayReadyManifestEBU-TT-D

H.265 *

AV1 *



Note1: *     H.265, VP9, AV1, WebM, Opus, Ogg Vorbis, Dolby AC3, Dolby E-AC-3, Dolby AC4, Widevine are conditionally required by the Device Specification [1] and might not be supported by devices. Apps MUST NOT rely on those technologies.

Note2:        All streams are supported with out-of-band subtitles (EBU-TT-D, WebVTT)
Note3:        Encrypted text tracks in container are not supported.

Printable versions of specifications

Current version:

Apps Requirements 2022

Version: 4.22

Date: 2021-12-28

PDF: VCA_4.22.pdf

Older versions:

Apps Requirements 2021

Version: 4.21

Date: 2021-12-28

PDF: VCA_4.21.pdf

Apps Requirements 2020

Version: 4.20

Date: 2020-09-07


Apps Requirements 2018

Version: 4.11

Date: 2018-02-22

PDF: Vewd Certify Devices 4.11.pdf

Apps Requirements 2017

Version: 4.10

Date: 2017-03-16

PDF: opera-tv-dcp-4.10.pdf

Application Requirements 2017

Version: 4.9.0-r1

Date: 2016-11-04

PDF: opera-tv-dcp-4.9.0-r1.pdf

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