Currently we use Cisco BAMS to get CDR files from PGW. BAMS converts the binary coded data into readable format. So it would be an advantage to import the binary data directly into splunk, if this is possible.....
Short answer: Probably, but that data is very unlikely to work with the Splunk for Cisco CDR app.
The Splunk for Cisco CDR app should really be called "Splunk for Cisco CallManager".
(Side Note: The app's current name was chosen in order to attract more technical users who were somewhat familiar with the raw CDR and CMR data. )
Anyway, the app is designed to work with the CDR and CMR data that comes out of Cisco CallManager. Cisco of course has a very broad set of products, even considering just the VOIP space. And each product tends to have its own data format. For instance Cisco CallManager Express, aka CME, has a very different data format for its CDR. We are actually close to releasing a new product for this data format, an app called "Cisco IOS Voice Gateway Reporting".
So, as far as practical advice, it is possible that the data you'd get out of BAMS matches this IOS voice gateway format. If you send a somewhat significant set of sample data to me (nick [at] sideviewapps.com) I can certainly index it and see if the app has any compatibility issues with it.
And even if it does not, I'd love to see the data anyway and it's quite possible we could make another sister product to analyze and report on this data, just like the Splunk for Cisco CDR app reports on CUCM data.