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Delivery specifications are produced by broadcasters and streaming companies to describe how contributing production studios should format and submit their assets for deployment. These are detailed documents and they cover all of the supporting assets that go with the program.

In order for the program to appear in the viewers dashboard, metadata needs to describe various properties of the program. Supporting text, graphics, posters, trailers and featurettes must all be present.

The Netflix delivery specification is a prime example of the level of fine-detail required to specify compliant delivery of programs from external producers. There are equivalent documents provided by all broadcast and streaming companies. They cover broadly similar topics with some details altered to suit their own ingest workflows.

Let’s step back from a specific case such as Netflix and look at the more generalized common requirements across a range of deployment platforms.

A Menagerie Of Specifications

This article is based on the contents of the specifications below.

The DPP initiative is particularly interesting because it allows for a more diverse distribution of content and reduces the number of different standards supported by each organization that adopts it.

Initially the DPP was created by the public service broadcasters in the UK. This quickly expanded to support the rest of the UK based broadcasters. Interest from AMWA and NABA in the USA extended the membership significantly.

Membership is open to any organization involved in making tools or producing content and now stands at over 500 members. Interestingly, while Apple, Google, Paramount, Disney and Amazon are members, Netflix is not yet part of the DPP family.

Component Assets

After scanning several delivery specifications, some important points emerge for consideration when planning.

When delivering content across multiple platforms, some of the assets may only be needed occasionally. It is prudent to develop a superset of the assets from the outset. This avoids the need to rework the production to fill in the gaps when a new platform is being populated. The means of recreating older assets may not be available later.

Always check the specification for the fine-details of what is required.

Metadata Content

If the metadata is prepared when the program project is first instantiated, it can be used to create a checklist of assets that must be provided to complete the manifest. The manifest can steer the workflow.

When the manifest is complete, the package is forwarded for final quality checks and delivered to the client content store once it is signed off.

The quality and breadth of the metadata you provide will affect how your content is found during user searches on the media platforms. If your metadata is incomplete or inaccurate then viewers won’t find your programs.

Metadata is often packaged in XML files. The character encoding of your metadata files should support Unicode to enable the widest possible set of international glyph symbols to be supported. The UTF-8 encoding is recommended. A byte-order mark (BOM) may or may not be required. Some platforms require it while others mandate that it is not present.

XML files are usually tagged at the start with a namespace attribute. This allows automation at the receiving end to validate the XML file according to the right schema.

More recently, JSON files may be used instead of XML. They are easier to create and parse and are often used by the JavaScript interpreter running inside a web browser.

The table below shows some important descriptive metadata items that you could provide. These don’t include technical properties of the essence that may be inherited from the production process:

Timecode Values

Timing values are best described in this format:

Expressing the sub-second time as a decimal avoids problems with frame-rate conversion. Multiple frame rate changes might float a frame index early or late due to rounding happening at each stage. A decimal value can be quantized to the nearest frame and remains stable.

The Apple Video & Audio Asset Guide and Apple TV+ guidelines have many more interesting metadata properties outlined with clear explanations which could be useful in other contexts as well.

Age-ratings

Each country has its own set of age ratings for film and TV content. In the UK, this is managed by the British Board of Film Censors (BBFC) and by the Motion Picture Association (MPA) in the USA.

This summary illustrates the age-ratings and how they compare between the BBFC and MPA:

Content Advisories

Here is a list of advisory category tags for content to be warned about in the user interface when customers are browsing for content to watch. Inclusion of any of these tags might mandate a parental guidance message or elevation to an older age-rating:

Video Assets

The main feature may be just one of several video component assets that are provided.

Video content is defined with the following properties. Not all of these may apply in every delivery specification. This is aggregated from the specifications listed elsewhere in this article. The delivery specification being applied to your project may constrain them to a smaller sub-set:

Video Display Method

Progressive display is much better than interlaced. There are unpleasant combing effects resulting from displaying interlaced footage on progressive displays. Converting interlaced footage to progressive requires sophisticated software to interpolate the missing lines. Interlaced archival footage should be converted (carefully) to progressive before shipment.

Pulldown Issues

Telecine conversions of movie film to TV formats need to accommodate the different frame rates.

A Telecine scanner clones fields and frames as necessary to approximate the desired frame rate. The frames are no longer in a simple steadily incrementing linear sequence. If interlaced video is created the effects are even worse with odd and even fields being taken from adjacent film frames. Removing this is complex and laborious. Telecine pulldown must be eliminated before shipment. If the video has been scaled after scanning, the undesirable artefacts are near impossible to remove.

Picture Formats (Image Sizes)

These are some typical picture formats taken from the Netflix specification:

You may only need to provide a few of these. SD, FHD and 4K are most likely although there are differences in SD sizes for Europe vs. USA platforms. Higher definition formats are more consistent worldwide.

Automated Picture Format Conversion

Some clients will happily crop down an HD image to SD by center-cutting a 4:3 aspect ratio image from a 16:9 original. This is not pan-and-scan but just a simple unsupervised crop.

Film directors generally dislike this happening to their movies and perceive it as an insult to their creativity. Sidney Pollack included a passionate and insightful presentation about this with the DVD extras for the 2005 film “The Interpreter” starring Nicole Kidman. The short documentary is entitled “Interpreting Pan & Scan vs. Widescreen”. Sidney points out that there is important plot related information being conveyed in the parts of the image that are cropped off and that the resulting film is NOT the one he made.

Leading & Trailing Black Frames

It is common practice for all video to begin and end with at least one black frame. This helps the switching automation to transition from one asset to another.

You are not expected to determine where advertising breaks will occur so this only applies at the start and end of the asset.

Content Duration

You may need to produce variants of the program with the duration adjusted to take account of commercial breaks. So a 60-minute version for broadcast on the BBC may require a 50-minute version for deployment on a commercial channel if the program is re-run later. A 90-minute program may need to be delivered as two 45-minute episodes.

Presenter Replacement

Presenters may be well known in one country but not another. Localizing the program for international markets may require replacement of the presenter so a version with and without the presenter visible on-screen might be requested.

Visual Rights Issues

If there are secondary video or copyrighted images in the background, they must be rights cleared. For example if a drama program has an episode of another TV show in view on a TV at the back of the set, then the use of that footage must be licensed for inclusion. Be aware that permission may not always be granted and it is not wise to take a chance and apologize later. That may be a costly mistake and hard to ‘fix in post’.

Leader-clocks

The BBC specification says that leader-clocks should be placed before your program starts. Read the delivery specification for exact details. The DPP specification mentions that these informational items may also be present. Some are mandatory:

• UUID/ISAN/V-ISAN.
• Series title.
• Series number.
• Episode title (optional).
• Telephone numbers.
• Production company branding.
• Moving clocks must have at least 7 seconds duration.
• Distinctly and abrupt incrementing changes at 1 second intervals.

Recaps & Trails

Recapping what happened in previous episodes and trailing what is happening in the next must be included with guidance from the client. The segments should not refer to specific times such as yesterday or next week as there is no guarantee that the programs will be broadcast with a predictable cadence or as expected.

Credits & Attribution

Adhere to the delivery spec for guidelines on how credits should be rendered. If you incorporate any logo artwork, this should also be included in the asset manifest.

Any calls to action should be removed as these are the responsibility of the broadcaster:

• No phone numbers.
• No hashtags.
• No web site URL references.

Credit should be given to ancillary content creators such as subtitling and metadata production staff or companies. This might not have been included in the end-credits of the video asset because it tends to be produced after the final edit stage. Likewise translation and localization content experts should be acknowledged.

Your client may require an end board to be placed after your program. They should supply this for you. This might have space for a copyright date, your logo and a text such as:

Moving Backgrounds

Some platforms require a moving background to be provided for the user interface backdrop. Apple TV+ calls this an Ambient Video Asset. It is required in several aspect ratios sizes and orientations. A vertically oriented format is required for use on iPhones for example.

Poster Frames

Videos can be tagged with a poster frame. This is a still image that is representative of the video content. It can be the first frame of the video file or it may be some other frame identified by a timecode elsewhere in the video. When the user interface is being constructed, this poster frame will be displayed in the video player rectangle as a placeholder and is replaced with the moving footage when the video starts playing.

Taste & Decency (Visual)

Broadcasters prefer to mask out nudity and vulgar content themselves according their own taste and decency guidelines. Streaming platforms tend to be more permissive in this respect since they are not governed by the same guidelines as on-air broadcasters. That may change.

A list of time-coded references to potentially offensive visual items should be provided in the manifest.

Part 2 is available HERE.