The final transfer of physical carriers to file formats for preservation should be done without quality loss. Usually the quality level of the signal retrieval from the original carrier determines the overall signal quality of the preservation process. In a mass migration process the technical quality of the used playback devices and the carefulness utilized in the transfer process is hard to estimate by inspecting the resulting files. Particularly by using an external service provider, spot checks and comparisons with in-house digitization will be a time consuming and still fragmentary approach to judge the quality of service.

Three methods have be presented, to close that 'analogue security gap'.

• Single-ended error detection based on transfer error models
• Full automatic reference-based error analysis using calibration media
• Automatic signal verification using multiple ingests of the same physical media

The three methods were compared and advantages, as well as limits of each method were demonstrated by using results from real-world mass migration projects. The three methods have been combined to complement each other.

The presented methods will enable a precise specification of the required signal transfer quality and will continuously document the technical quality of the used playback devices and analog to digital converter. The in-house quality management will benefit from this and the new parameter can become part of the description of the level of service.

A service provider will be able to provide certified parameter of the technical transfer quality, as an online service to his client. For this the parameter can be visualized in easy understandable graphics within an Internet browser window. The presentation is focused on the supervision of audio signal paths. An outlook on corresponding technology for motion pictures will be provided.