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 & Compliance

AudioTools 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:

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 fi le to mono WAVs
  • Mono WAVs to BWF
  • Compliant 16, 24 and 32 bits

Source files for non-SMPTE 337M analyses can also be linear PCM, in either WAV or Broadcast WAV (BWF) format, without Dolby E essence.

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 Analysis

Another 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 Measurement

AudioTools Loudness Measurement performs measurements directly on the audio content in order to verify the loudness settings 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.

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