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Relation between SAI clocks and frame sync frequencies

Question asked by tom301 on Feb 4, 2016
I find that the STM32F4 reference manuals are a bit confusing regarding the relation between the SAI clocks SAI_CK_x, MCLK, SCLK and the FS frequency
Are the following 2 interpretations correct?

1) In master mode with NODIV=0, is the divisor of 256 always present and fixed at 256? Is the frame sync frequency always FS = SAI_CK_x / MCKDIV / 2 / 256? and SCK_x = SAI_CK_x / MCKDIV / 2 * (FRL + 1)  / 256.
   The reason it is not clear to me is because the reference manual states "In the SAI, the single ratio MCLK/FS = 256 is considered." which is then followed by an example. So it is not clear whether the word "considered" implies that 256 is just an example and nowhere in the document is there explicit reference to a fixed divisor of 256.

2) In master mode with NODIV=1, is the frame sync frequency FS = SAI_CLK_x / FRL ? and SCK_x = SAI_CLK_x ?