Layer 2 — Modular Design

Essence Extraction

Many Workflows entail source files in a format other than linear PCM. Dolby E is an example of a common audio format that must be decoded prior to further action. Video containers are another common format in many workflows, where the audio essence must be extracted from the container before that material can be processed.

For audio within QuickTime or MXF containers, AudioTools Server extracts audio essence without accessing, copying or altering the video essence. This saves time and ensures video integrity.

Data Discrimination

AudioTools Server can not only decode Dolby E, but it can also distinguish between “pure” linear PCM and PCM carrying a Dolby E payload. This allows your Workflow to automatically handle mixed un-encoded and Dolby E encoded WAV files. AudioTools Server will also detect whether the material is stereo or multichannel and, if surround, which channels are front, center, surround and LFE.

These discrimination operations are all performed on the essence itself since headers or metadata alone cannot be trusted. This small but valuable part of AudioTools Server’s repertoire enables unattended operation in environments where a wide variety of source files are expected.

Measurement & Validation

Once your audio material has been validated, extracted or decoded, it can be processed further. One of the most pressing issues in today’s broadcast environment, program distribution and OTT content management today is assessment and control of perceived audio loudness. AudioTools Server has two measurement modules available, AudioTools Loudness Measurement and Dolby® Media Meter 2. Both modules measure subjective loudness according to the ITU-R BS.1770-1, BS.1770-2,
ATSC A/85:2011a and EBU R 128 standards. Both also feature Dialogue Intelligence, a patented technology that automatically detects speech in your audio tracks and only then measures loudness.

Whichever module you use, all mandated metrics are supported, including Program Loudness, Maximum Momentary and Maximum Short Term Loudness plus Loudness Range, Average ITU (LKFS), Maximum Sample Peak Loudness and True Peak. The BS.1770-2 specification includes optional and adjustable amplitude gating. AudioTools Server can be specifically configured as an AudioTools Loudness Control Server turnkey package.

Constant Compliance

After measurement, it’s often necessary to alter audio essence so it conforms to local standards. Many loudness control solutions employ audio processing, left over from NTSC and PAL workflows, that shoehorns your content into a pre-defined loudness envelope. As part of an agile loudness control system as recommended by the ATSC, AudioTools Server can be configured to apply a single gain correction to the entire program, without dynamic range modification or peak limiting, which ensures the best possible fidelity. If correction is applied, AudioTools Server can modify or replace missing metadata to direct the consumer’s decoder to the desired playback gain. It can also validate and correct Dolby Digital and Dolby E metadata and Dolby E framing errors based on a prior measurement step. As a versatile loudness engine for any file-based loudness control strategy, this is only one of several loudness control Workflows that can be realized with AudioTools Loudness Control Server.

For material that already meets predefined parameters, AudioTools Server bypasses any processing and leaves the file untouched. On the other hand, for exceptional material, a multi-band dynamics package can be brought into play, to expand, compress and peak limit as necessary. Alternatively, AudioTools Server can set aside any file that cannot be processed sensibly, so manual intervention can take place.

RePack & ReConfigure
Enterprise-class automation demands more than simple unwrapping and rewrapping. Complete post-processing channel management requires unwrapping, essence manipulation and channel re-configuring prior to rewrap.
All are easily accomplished with AudioTools Server’s ability to remap channels and transcode formats as needed. For instance, four stereo pairs can be upmixed to 5.1, an LtRt can be generated, and the resulting 3/2 + 2/0 files can be inserted back into their parent container or, re-encoded with SurCode for Dolby E. Format and file type changes, up/downmixing, channel management, watermarking or any other required audio processes can be inserted between decoding and re-encoding.

Always On The Job
AudioTools Server supports automated, semi-automatic, and manual modes or a combination. For instance, normal operation can be automated, with manual exception handling. Utilizing AFP and SMB protocols, semi-automated
operation can be driven by watched folders, while file access can be local or networked. AudioTools Server employs two separate watch folder methods, Watch-for-Content or Watch-for-Job.

With a Content-driven Workflow, files dropped into a Watched Folder are copied to undergo predefined processes or processing chains, and are then output to a specified location. Incoming XML job descriptions power Watch for Job Workflows, where a Watched Folder acts as a clip bin for incoming XML job descriptions, processing directly on shared storage.

Always Up To Date
Got a new Workflow you need to implement? Simple Job setup is easy with AudioTools Server’s Job Wizard, which guides you through the process of creating a novel job or template. For more elaborate Workflows, the optional AudioTools WFC module is available in conjunction with Minnetonka Audio’s professional services team, who can help tailor complex, conditional and adaptive Workflows that address your specific production needs.

Each AudioTools Server is delivered with stock job definitions and Workflows. To completely leverage your investment and utilize every aspect of its flexible and powerful personality, the professional services team will assign a dedcated engineer to adapt your current working methods to an automated, hands-free approach.

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