Flac doesn't really need to know what the actual sample rate is; you could tell it 500e3 and you should get the same data out after compressing and decompressing it.
On Sat, Jul 16, 2016 at 11:20 AM, Dave NotTelling <[email protected]> wrote: > Marcus & Dan, > > Thank you very, very much for the detailed information! > > Dan: That's exactly what I thought when going into this at first. But, I > decided to give gzip a shot just to see how well it did. Turns out that (at > least for bursty environments) it almost halves the size of the original > file. It should be noted that the file was in fc32 format so there were > likely a lot of unused bits there (or so I guess). > > Marcus: I have been giving thought to truncating some of the bits. Going as > far as thinking about dropping from sc16 to sc8. I have worked with 8 bit > sample files before and had plenty of success demodulating, so I'm thinking > that it might be an okay path to go down. Dynamic range goes to hell, but > it it's worked in the past... I think that re-packing as 12 bit would give > considerable space savings without a lot of CPU overhead. I'll have to give > that one a go :) I really like your idea of using FLAC. Just a quick > Google search netted http://www.rtl-sdr.com/compressing-filtering-iq-data/. > What concerns me is that when I tried to use the command line flac in Ubuntu > it said that the sample rate must be between 1 and 655349 Hz. I'll have to > poke around at it to see what happens when I set an incorrect bit rate > (maybe a multiple of will be fine?). > > Thank you both! > > -Dave > > On Sat, Jul 16, 2016 at 5:14 AM, Marcus Müller <[email protected]> > wrote: >> >> Ah! >> >> On 16.07.2016 11:04, Marcus Müller wrote: >> > and maybe, but this is really speculation, you can just modify the >> > error calculation to just ignore the 4 lower bits of the actual sample >> > data, and safe another few percents of data volume. >> Yeah, there's a FLAC__stream_encoder_set_bits_per_sample[0] function-- >> guess that you don't need to modify anything. Also, there's a whole >> listing of things .._set_compression_level[1] sets internally. This >> approach (using FLAC as lossless waveform encoder) might be really >> interesting. >> >> >> >> [0] >> >> https://xiph.org/flac/api/group__flac__stream__encoder.html#gabfa3c989377785cda7c496b69dcb98cb >> [1] >> >> https://xiph.org/flac/api/group__flac__stream__encoder.html#ga07fc8c7806381a055a1eef26387e509f >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- GDB has a 'break' feature; why doesn't it have 'fix' too? _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
