Question about minimp4_test.c

[Ahmad Nofal]

Thank you for your work on this great and helpful project, wanted to ask you about a certain line in the test that I could not understand
Here in minimp4_test.c
in_args.numInSamples = 1024;
Why are setting the number of samples to 1024, I am very new to A/V if this is a stupid question. I can see the same value used throughout the file in relation to audio but cant know what it signifies.

Also why is the aac encoder output size is set to 2048 but the output_element_size is set to 1, how is the calculation done ?

Thanks