Relevant Quality Control for the File-Based Automated Environment

Relevant QC

With the proliferation of distribution channels, the broadcasting landscape is expanding geometrically. As con-tent is continually repurposed for new target formats, the potential for errors increases in proportion. And while qual-ity control solutions for video have kept pace with today’s workflows, comprehensive audio QC remains a challenge for many of today’s production platforms. Issues with audio quality and loudness, channel configu-ration and formatting, encoding and metadata, etc. are beyond the scope of the more video-centric QC tools.

With today’s file-based workflows, QC and verification is essential to ensure file integrity, compliance with new loudness regulations and compatibility with the next stage in that content’s lifecycle. Min-netonka Audio, in collaboration with leading broadcasters and studios, identified the most critical QC tasks for both Dolby E files and PCM audio content and incorporated them into AudioTools Quality Control Server.

We Do Audio

AudioTools Quality Control Server provides automated QC and verification of Dolby E formats and delivery specs. AudioTools Server’s QC also intelligently screens the PCM audio itself for surround channel identification, program cor-relation, and playback anomalies such as clicks, pops, and silence.

AudioTools Quality Control Server features individual modules tai-lored to each audio essence type and can be configured to handle mul-tiple types simultaneously, including:

• Format and metadata validation • Correction and compliance• Essence integrity • Channel assignment • Loudness conformance and rectification • Transient/click and loss of program detection• Program correlation/comparison

These tools and more are managed and regulated according to your company–defined rules and standards. Further automation is accomplished through the AudioTools Workflow Control module, a decision engine that processes and adjusts audio proper-ties according to predefined instruction sets and parameter ranges. AudioTools Workflow Control also manages load balancing in multiple-server deployments.

Use Case

Dolby E Quality Control

AudioTools Quality Control Server for Dolby E is comprised of the following QC modules:

• Dolby E WavFileAnalyzer• AudioTools Metadata Verifier• AudioTools Loudness Measurement

AudioTools Dolby E WavFileAnalyzer – Dolby E Validation & ComplianceAudioTools Dolby E WavFileAnalyzer operates directly on the file’s data essence, without the need to decode the contents. WavFileAnalyzer performs a detailed analysis of the SMPTE 337M based Dolby E file structure and can correct the Dolby E line position in the file.

The AudioTools Dolby E WavFileAnalyzer Module inspects the file the following key areas:

The results of the processing are formatted in XML and can be classified as Errors, Warnings, and Information. Post analysis workflow options, such as processing file types and formats, and SMPTE alignment correction can be used within the QC processor as a separate job or can also be included in the analysis step directly. Correcting the Dolby E line position fixes the number one reason for rejecting Dolby E files.

AudioTools Metadata Verifier – Metadata AnalysisAnother critical problem with Dolby E content is inconsistent metadata within the Dolby E stream, which can cause transmission mutes and other audible anomalies. The Metadata Analysis processing phase decodes the metadata for each frame of the Dolby E stream and for each program within the stream. Dolby E and program metadata are checked for consistency across all frames. In combination with the AudioTools Loudness Measurement module, AudioTools Quality Control Server for Dolby E also verifies the loudness information in the metadata against the measured loudness values in the audio file.

AudioTools Loudness MeasurementAudioTools Loudness Measurement performs measurements directly on the audio content in order to verify the loudness set-tings in the metadata. AudioTools Loudness Measurement supports all international loudness standards, such as ITU-R BS.1770 (including ITU-R BS.1770-2), EBU R 128 as well as ATSC A/85. If the metadata does not accurately reflect the content loudness, the new measurement metadata value can be applied before the content is encoded back to Dolby E. This is also true in cases where the loudness measurement standard is supposed to be changed, which might result in a different loudness value.

Alternatively, the file’s audio loudness can be adjusted to a new standard and/or set of loudness values by adding AudioTools Loudness Adjustment to the QC environment, which automates adjustment to the new target loudness values. See AudioTools Loudness Control document for more details.

Chunk analysis (all fields) BWF or RF64 Files:

• RIFF, RF64, ds64, fmt ,data, dbmd, BEXT, and LIST

• Name and size of any other chunk

SMPTE 337M analysis:

• SMPTE 337M Pa, Pb, Pc,

Pd spacing all along the file

• SMPTE 337M alignment with video

• SMPTE 337M quantification

• SMPTE 337M video format (PAL or NTSC)

• File duration

Peak detection:

• Peaks over -3dBFS in stereo

and multi-mono WAV files

Processing:

• SMPTE alignment

• BWF file to mono WAVs

• Mono WAVs to BWF

Source files for non-SMPTE 337M analyses can also be linear PCM, in either

WAV or Broadcast WAV (BWF) format, without Dolby E essence.

Quality Control for PCM audio content

AudioTools Quality Control Server for PCM analyzes the audio content and uses unique modules to identify potential issues.

• AudioTools Audio Quality Analysis• AudioTools Channel Assignment Detection• AudioTools Program Correlation Check

AudioTools Audio Quality AnalysisWhile there are an unlimited number of potential problems that can be screened for in the analysis of audio content, the most critical issues for a broadcaster are clicks and crackle, and silence. The AudioTools Quality Analysis module uses a series of algorithms to analyze incoming PCM audio content and detects anomalies such as clicks and silence. Parameters may be speci-fied to control the algorithm processing, and each algorithm may be enabled or disabled. The output log indicates the types of anomalies found and the time code locations where they occurred.

AudioTools Channel Assignment Detection – Channel ConfigurationsHow can you determine whether the channel assignments indicated in your database records and metadata accurately reflect the content’s actual channel configuration? The AudioTools Channel Assignment Detection module determines channel loca-tions within multi-channel programs by evaluating relative loudness levels, channel correlations, and frequency range on a representative section of the audio. The module then algorithmically identifies likely channel pairs; front, rear, center, and LFE, extending the sample range until the desired level of confidence for each assignment is reached.

AudioTools Program Correlation CheckMultiplatform and multi-device broadcasting require that the same content is generated and handled in a number of formats. This can be a simple 5.1 + 2 configuration or a large number of content-wise identical files for web, mobile and other devices and platforms. How do you know that there is indeed the same content in those files, from start to end?

The AudioTools Program Correlation module performs a correlation check between two audio programs and is used to deter-mine whether both represent the same content. An initial alignment step is performed to account for small differences in the start of each program. The number of channels in each program may hereby range from 1 to 8.

These modules can be used separately or as part of a complex and conditional ingest or QC process, in combination with other AudioTools modules or integrated with 3rd party QC or workflow platforms

Operation and integration of AudioTools Server is possible in a number of ways.

• For custom integration with existing digital asset and content management systems, full access to the AudioTools Server automated feature set is available via Web Services (SOAP/XML). This standardized yet extensible development interface provides complete, programmatically addressable access to all of AudioTools Server’s capabilities.• “Watch” or “hot” folders can be created, into which asset files are copied to a network directory that is monitored by AudioTools Server. AudioTools Server can also monitor a watch folder for XML job description files instead of the assets themselves. This enables AudioTools Server to work directly on shared storage, eliminating the need for large network file copies.• The AudioTools Server Sample Client utility, available for Windows, Mac, and Linux, offers an easy and straightforward simple GUI for managing and monitoring AudioTools Server jobs manually.

AudioTools Server Modules

AudioTools Server Module Description

AudioTools Dolby E WavFileAnalyzer QC analysis and correction module for Dolby E file structure.

AudioTools Metadata Verifier QC module for Dolby E metadata.

AudioTools Loudness Measurement Loudness measurement according to ITU-R BS.1770, EBU R128 and ATSC A/85 specifications.

Dolby Media Meter Loudness Measurement option for Dolby Dialogue Intelligence™.

AudioTools Loudness Adjustment Loudness Adjustment according to ITU-R BS.1770, EBU R128 and ATSC A/85 specifications.

AudioTools Upmix Upmix modules, stereo to 5.1 or 7.1 multi-channel audio.

AudioTools Downmix Downmix from 7.1 or 5.1 to stereo, including optional dynamic range adjustment.

SurCode for Dolby E Encoder/Decoder Encoder / Decoder module for Dolby E with full metadata support.

SurCode for Dolby Pro Logic II Encoder/Decoder Encoder / Decoder for Dolby Pro Logic II, can be combined with AudioTools Downmix.

SurCode for Dolby Digital Plus Encoder/Decoder Encoder / Decoder for Dolby Digital Plus and Dolby Digital.

SurCode for Dolby Pulse Encoder/Decoder Encoder / Decoder for Dolby Pulse, AAC and HE-AAC.

AudioTools Audio Extractor for MXF Extractor for audio and metadata store in MXF files.

AudioTools ReWrap™ for MXF Output module for laying audio data back into an existing or new MXF file.

AudioTools Audio Extractor for QuickTime™ Extractor for audio streams from QuickTime formats including Apple ProRes, H.264 and MPEG-2 video formats.

AudioTools ReWrap™ for QuickTime™ Output module for laying back audio into the QuickTime format including Apple ProRes, H.264 and MPEG-2 video formats.

AudioTools Channel Manager Audio channel and program handling and replacement in multi-channel audio files.

AudioTools Watermarking Module for adding Civolution™ watermarking to the audio essence.

AudioTools Workflow Control Module for adding complex and conditional workflows or for load balancing between multiple AudioTools Servers.

AudioTools Audio Quality Analysis Analysis of audio content for anomalies such as clicks or silence.

AudioTools Channel Assignment Detection Detection of the channel location within a multi-channel program based on audio content.

AudioTools Program Correlation Check Correlation check between audio programs to dertermine whether they represent the same content.

Customer defined and 3rd party modules AudioTools Server has been designed to host customer defined and 3rd party modules.

See AudioTools Module Description document for more information.

17113 Minnetonka Blvd Minnetonka, MN 55345 USA Phone +1 952 449-6481 Heimbachstrasse 40 D-41747 Viersen, Germany Phone +49 2162 1062622

www.minnetonkaaudio.com contact@minnetonkaaudio.com

20110901

AudioTools Server and SurCode are trademarks of Minnetonka Audio Software, Inc. Dolby®, Pro Logic®, Pro Logic II®, Dolby Digital®, Dolby® E and Dolby® Media Meter are all registered trademarks of Dolby Laborato-ries. DTS, THE SYMBOL AND DTS + THE SYMBOL TOGETHER ARE REGISTERED TRADEMARKS OF DTS, INC. QuickTime and the QuickTime Logo are trademarks of Apple Inc.

For more detailed information and tutorials for AudioTools™ Server please visit our website:www.minnetonkaaudio.com

September 2011