Added clipping of the buffer level to maximum_buffer_size

The buffer level was not being capped at the maximum decode
buffer size specified by the user.

In CBR mode this resulted in large files being generated
immediately after a dramatic reduction in the data rate
target. This fix should prevent this from happening.

Change-Id: Iaf01c9fb037cf51515217a5834d6ee4fbb0cb853
2 files changed