Problems of Forensic Sciences 2016 Vol. 105 (CV) 351-369
TEST AUDIO RECORDINGS AND THEIR USE IN AUTHENTICITY EXAMINATIONS. DATABASE OF PROPERTIES OF DIGITAL AUDIO RECORDERS AND RECORDINGS
Marcin MICHAŁEK
Institute of Forensic Research, Kraków, Poland
Streszczenie
Currently, there are many brands and models of devices with a digital audio recording function and with different recording parameters. At present, experts almost exclusively receive digital devices and recordings stored using digital technology for forensic audio examination – these have almost entirely replaced analogue techniques in the field of multimedia. The aim of this study was to collect devices with a digital audio recording function, and then make test recordings with these devices and determine the possibility of converting them into a standard format. A database containing the parameters of the analysed recorders and their recordings was created as part of this study. The test recordings were made in available recording formats for each recorder and under different acoustic conditions. It was determined that the largest groups of analysed recorders was voice recorders (75%), followed by mobile phones (19%) and other devices with an audio recording function, such as multimedia players, tablets and cameras (6% in total). The test recordings were made in 18 different recording formats, which were characterized by different quality and parameters. The most numerous formats were: WAVE ADPCM, WMA and MP3. The conducted research and results, as well as the constructed database, are helpful for experts investigating the authenticity of audio recordings.
Słowa kluczowe
Authentic recording; Database; Digital recorder; Test recording.