On Fri, Apr 01, 2005 at 02:06:53PM -0500, James Cooley wrote: > Hi all, > > There was some talk a few weeks back on creating a file format in which > there's a header storing info like the sample rate, capture freq, > decimation, etc. > > I would like to create such a file, but would like to store some small > amount of data once per work cycle. The idea is to constantly record a > changing freq and other data and be able to play it back later. > > I followed the model of file_sink/file_source and designed format like > this: > > <int> length of header stuff (could be 0) > <int> header ints > .... The sample data > > <int> length of header stuff (could be 0) > <int> header ints > .... The sample data > > <int> length of header stuff (could be 0) > <int> header ints > .... The sample data > > So far this doesn't work because of my assumption of the sample data > size. Am I assuming correctly that sample data (n_input_items) items is > a fixed size?
No. Not a safe assumption. The only thing your work routine can count on is that it will be called with noutput_items = k * output_multiple() for some integer k. > How is that determined in the flow graph? It's an implementation detail that is subject to change depending on the implementation of the scheduler. > Will it be the same when I go back to read in the file? (I think > not, this is why my code fails, it assumes that it will find my > header info (size, header) at the start of each work cycle when > reading in the file). Unlikely ;-) I think you can get what you want by including the length of each chunk of data in the file. > <int> length of header stuff (could be 0) > <int> header ints > <int> number of samples in this chunk > .... The sample data > <int> length of header stuff (could be 0) > <int> header ints > <int> number of samples in this chunk > .... The sample data Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio