I do not have access to 3CX code, so I can only guess at the cause. However, coincidently, there is a 25 MB file size limit with OpenAI and Azure. It is important to understand that 3CX saves recordings at
approximately 1 MB per minute, so as you approach 25 minutes the file size will be very close to the maximum permitted file size. I don't know whether there is a similar file size restriction with the 3CX AI since I do not believe they have ever mentioned what AI they are using.
To get around the 25 MB file size limit, programmers can use "chunking" which essentially means splitting up larger files into smaller pieces (chunks) and then sending the chunks to AI. AI will analyze all the chunks and return a single result.
As I said, I do not have access to 3CX's code, so I cannot be certain this is the cause, but it seems possible 3CX is not chunking larger recordings.
If you are having issues processing larger recordings, I encourage you to take a look at our
3CX Recording Manager tool. We support analyzing multi-hour long recordings.
In the example above, you can see we provided a transcription, agent score (based on our "Ask AI Anything" feature), and much more for a phone call that was nearly two hours long.