Extracting session audio from OCS 2007 Speech Server logs
The ability to extract the audio for an entire call (both prompts and recognitions) from the Speech Server 2007 logs is a really useful feature for a number of analysis and tuning scenarios. Since the topic has surfaced a few times on the Beta newsgroups, here's a summary of how to do it.
1. Ensure your logging parameters for the server are set (via the Trace Logging tab in the Administration Console) to log Application Events and All audio for: 100% of calls.
2. When you import the log data into the database with the MssLogToDatabase utility, be sure to specify the flag /audio:session.
3. In Analytics and Tuning Studio, connect to the database and in the Session List View or Session Detail View select the call that you want to hear. Hit the Play Session Audio button to play it back using your default .wav player, or hit the Export Session Audio button to export to file.
Some notes:
1. The logging of prompt audio is not available with TIM deployments of Speech Server (i.e. you need to be running a VoIP gateway).
2. The prompt audio as recorded does not take account of any dynamic changes to timing or volume. (So if, for example, the caller accelerated or decelerated playback while the prompt was underway, you won't hear the changes, and you may notice timing mismatches on the concatenated output file. You can check for these cases by looking for the relevant event signalling the prompt rate change in the session details.)
3. Some scenarios may call for access to the audio data in environments outside Analytics and Tuning Studio. For some sample code that illustrates how to extract the audio programmatically from an OCS 2007 database, see this article. (Extracting session audio is not possible with the command line utility MssContentExtract.exe, which be used only for extracting recognition audio.)
