Digital Assets 
by: Lawrence Harte

A digital asset is a digital file or data that represents a valuable form of media. Digital assets may be in the form of media files, software (e.g. applications) or information content (e.g. media programs). 

Digital content is raw media (essence) that is combined with descriptive elements (metadata). Metadata is information (data) that describes the attributes of other data. Metadata or meta tags are commonly used to provide technical and descriptive information about other data. (metadata is data that describes other data). A television program may contain technical metadata that describes the media encoding formats and duration of the media along with descriptive metadata that provides information about the title and actors.

In addition to digital assets that may be acquired or originally recorded (such as video from a sports game), digital assets may be combined to create new digital assets through the production and editing process. This process produces secondary content. An example of secondary content is the creation of "sports highlights" from a series of games that were previously broadcasted. 

Digital assets are typically stored in a high resolution version so they that can be converted (transcoded) into lower resolution formats as required. High-resolution digital assets require and extensive amount of storage area so older or less used digital assets are commonly moved to offline repositories. The original digital assets (master files) are commonly stored in a secure area (called a "vault") which usually has restrictions on use or have usage costs associated with the content. This vault may be an electronic storage facility (e.g. video disks) that is protected by a password system and data network firewalls.

Some of the key types of digital assets include digital audio, images, video, animation and application programs. There can be many other types of digital assets including web pages, scripted programs (e.g. Javascript files), fonts and other types of media that can be represented in digital form.

Digital Audio (Voice and Music)

Digital audio is the representation of audio information in digital (discrete level) formats. The use of digital audio allows for more simple storage, processing, and transmission of audio signals.

The creation of digital audio typically involves the conversion of analog signals into digital formats (it is possible to create synthetic audio without analog signals). The conversion process determines the fidelity of the digital audio signal. Audio fidelity is the degree to which a system, or a portion of a system, accurately reproduces at its output the essential characteristics of the signal impressed upon its input.

The typical data transmission rate for uncompressed high quality audio is 1.5 Mbps (for 2 channels of audio). This requires a data storage area of approximately 11 MBytes for each minute of storage. Digital audio is commonly compressed (coded) to reduce the amount of storage that is required for the audio. There key ways that digital audio may be coded including waveform coding, media or perceptual coding. Broadcast audio is commonly compressed and transmitted in an MPEG format (e.g. MP3) at 128 kbps.

Waveform coding consists of an analog to digital converter and data compression circuit that converts analog waveform signal into digital signals that represent the waveform shapes. Waveform coders are capable of compressing and decompressing voice audio and other complex signals. 

Media coding is the process of converting an analog waveform into components that represent its underlying media format. For example, speech coding analyzes the analog signal into codes that represent human sounds. Media coders typically provide a substantial amount of compression (8:1 ore more). However, media coders are only capable of transforming signals of the media types they are designed for. This 

Perceptual coding is the process of converting information into a format that matches the human senses ability to perceive or capture the information. Perceptual coding can take advantage of the inability of human senses to capture specific types of information. For example, the human ear cannot simultaneously hear loud sounds at one tone (frequency) and soft sounds at another tone (different frequency). Using perceptual coding, it is not necessary to send signals that cannot be heard even if the original signal contained multiple signals. MP3 coding format uses perceptual coding.

Images

Images are data files that organize their digital information in a format that can be used to recreate a graphic image when the image file is received and decoded by an appropriate graphics application. Images may be used within or added to (e.g. logos) program materials.

The creation of digital images may involve the conversion of pictures or images into digital formats (e.g. scanning or digital photographing) or it may be through the creation of digital components (image editing). 

The resolution of the image is determined by the number of pixels per unit of area. A display with a finer grid contains more pixels, and therefore has a higher resolution, capable of reproducing more detail in an image. The raw file size is determined by how many bits represent each pixel of information. A single image that has high resolution can require over 200 MBytes per image (600 dpi x 11" horizontal x 600 dpi x 17" vertical x 24 bits (3 Bytes) per pixel = 200+ MBytes). 

Animation

Animation is a process that changes parameters or features of an image or object over time. Animation can be a change in position of an image within a video frame to synthetically created images that change as a result of programming commands.

Animation media is the set of data and images along with their controlling software commands that are used to produce animated displays. The production of animated images may be performed at the broadcaster's facility or they may be performed at the viewer's location (e.g. gaming applications).

Digital video is a sequence of picture signals (frames) that are represented by binary data (bits) that describe a finite set of color and luminance levels. Sending a digital video picture involves the conversion of a scanned image to digital information that is transferred to a digital video receiver. The digital information contains characteristics of the video signal and the position (or relative position) of the image (bit location) that will be displayed.

The typical data transmission rate for uncompressed standard definition (SD) television is 270 Mbps and uncompressed high definition (HD) digital video is approximately 1.5 Gbps. This requires a data storage area of approximately 200 MBytes for each minute of standard definition storage and more than 11 GBytes for 1 minute of high definition television storage. 

Digital video is commonly compressed (coded) to reduce the amount of storage that is required for the video. The ways that digital video may be coded (compressed) including spatial compression and temporal compression. Spatial compression (within a frame) is the analysis and compression of information or data within a single frame, image or section of information. Temporal compression (between frames) is the analysis and compression of information or data over a sequence of frames, images or sections of information. 

Combining spatial compression and temporal compress, the data transmission rate for digital video can be reduced by 200:1 or more. Broadcast video is commonly compressed and transmitted in an MPEG format at 2 to 4 Mbps (2 hours of video is approximately 4 GBytes = 1 DVD). During the editing and production process, the use of compression is minimized to ensure the quality of the original materials.

Data Files (Books and Databases)

A data file is a group of information elements (such as digital bits) that are formatted (structured) in such as way to represent information. While the term data file is commonly associated with databases (tables of data), a data file can contain any type of information such as text files or electronic books.

Digital asset management is the process of acquiring (ingesting), maintaining (managing assets), and distributing (broadcasting and transferring) digital assets.

Ingestion

Ingesting content is a process for which content is acquired and loaded onto initial video servers (ingest servers). Content ingestion may come from several different sources including satellite downlinks, stored media (DVDs, tapes) or data connections.

While ingestion may be directly controlled from media players (such as DVD players), some content is transferred via data networks and there is a cost associated with the transfer of information through these networks. In general, as the data connections speed and distance increases, the cost of the data connection dramatically increases. As a result, some media may be ingested slowly to allow for the user of 

Cataloging

Cataloging is the process of identifying media and selecting groups of items to form a catalog or index of the stored media. As media is ingested into a DAM system, it is identified (labeled) along with key characteristics and added to the catalog of materials. Cataloging is a key part of the asset manager.

The first step in cataloging is labeling (logging) the digital asset when it is acquired or created. After the digital asset is identified, additional information is associated with the digital asset. This information may be technical or descriptive data. Much of this information may already be available within the metadata portion of the asset that is ingested.

The cataloging process is becoming more automated and much of the metadata that is already provided with the media may be automatically imported, categorized and stored with the digital asset. To ensure that descriptions are clear and compatible between networks