SC-03-12 meeting report, 2008-05, Amsterdam

Report of the meeting of the SC-03-12 Working Group on Forensic Audio of the SC-03 Subcommittee on the Preservation and Restoration of Audio Recording, held in Amsterdam, the Netherlands, 2008-05-18

The meeting was convened by vice-chair E. B. Brixen.

At present time there was no report from the previous meeting, 2007-10-07.

Open projects

AES27-R: Review of AES27-1996 (r2002): AES recommended practice for forensic purposes - Managing recorded audio materials intended for examination

Assigned to: SC-03-12, Initiated: 2007
Intent: Review, Target: 2012
Current goal: Status report, Goal date: continuing
Status: AES27-1996 (r2007) reaffirmed 2008-02-05.
No action was requested or required.

AES43-R: Review of AES43-2000: AES standard for forensic audio - Criteria for the authentication of analog audio tape recordings
Project scope: This standard specifies the minimum procedure for the authentication of analog audio tape recordings intended to be offered as evidence or otherwise utilized in civil, criminal, or other fact finding proceedings. It does not specify or restrict additional testing procedures that can be used.

Assigned to: SC-03-12-C, Initiated: 2005
Intent: Review, Target: 2010
Current goal: Status report, Goal date: Continuing
Status: No action requested or required.
Discussion: The contents of this document were not under discussion. However, it was considered how to manage separate documents for the authentication of analog recordings and the authentication of digital recordings. In that respect the ENF methodology is just one tool out of several for the digital recordings. Preferably we will form a task group to take care of this work.

Development projects

AES-X135: Forensic audio - Recordist Audio Evidence Collection (FARAEC)

Assigned to: SC-03-12, Initiated: 2002-10
Intent: Information document, Target: 2008
Current goal: PWD, Goal date: 2008-10
Status: Draft to be formatted as a PWD
Discussion: W. Dooley has produced a draft and the initial formatting has been prepared by M. Yonge. Dooley stated that two specific areas are open for further input, the implementation of the ENF methodology, and the still increasing resolution of digital media. It was discussed how the ENF methodology could be reflected in this document and the conclusion was that the progress in the ENF task group should be followed closely in order to find the right way to prepare recordings for a possible ENF extraction. A broader discussion took place on the storage and authentication of these recordings. Various techniques involving GPS-data, uploading recordings to a safe site on the internet, utilizing specific hum injection, etc., were mentioned.

It was decided to continue the work on this document in order to bring it one step further before next meeting in San Francisco. Brixen and Dooley will make it happen.

AES-X172: Forensic analysis of Electric Network Frequency (ENF)

Assigned to: SC-03-12, Initiated: 2007-05
Intent: Standard, Target: 2008
Current goal: PTD, Goal date: 2007-12
Status: AES-X172 initiated and assigned to SC-03-12
Discussion: There is a lot of ongoing work regarding the ENF technique. It is understood that a number of papers on the topic will be presented at the AES33rd International Conference in Denver, 2008-06. By then, the documentation on the North American grids should be in place. Some work on the limitations of the technology is still necessary as it cannot be applied to all digital recordings. In some cases no traces of ENF can be found. However, there is a wide interest for this technology so it is a hope that the writing of the document can take place soon.

New projects

It was discussed that there is a need for a document on acceptable forensic practice for speech enhancement of sound recordings intended for voice identification. It was mentioned by G. Reid that Cedar Audio has a small document that defines the influence on the speech signal from the signal processing. It is suggested that this topic is brought up in the AES-TCAF (Technical Committee on Audio Forensics). Any writing of white papers or any other documents can be brought back to the SC.

New business

There was no new business. The next meeting will be scheduled in conjunction with the AES 125th Convention in San Francisco, CA., US, 2008-10.

AES - Audio Engineering Society