In RTL_SDR, option -b
What does: "output_block_size (default 16*16384)" mean?
I have been searching and I just can't find that explained anywhere.
Thanks, Pete
Hi Pete,
On 31/05/2019 19.59, P C wrote:
In RTL_SDR, option -b
What does: "output_block_size (default 16*16384)" mean?
I have been searching and I just can't find that explained anywhere.
It's the size of the buffer that's used while capturing in synchronous mode.
http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n143 http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n174 http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n236
Regards, Vasil
Vasil,
Thank you for the prompt reply. And thank you for not chastising me for saying I searched but you found the links for me.
Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. I was hoping for something like, The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......).
Would you know where can find that kind of information?
Thanks again,
Pete
On 5/31/2019 3:14 PM, Vasil Velichkov wrote:
Hi Pete,
On 31/05/2019 19.59, P C wrote:
In RTL_SDR, option -b
What does: "output_block_size (default 16*16384)" mean?
I have been searching and I just can't find that explained anywhere.
It's the size of the buffer that's used while capturing in synchronous mode.
http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n143 http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n174 http://git.osmocom.org/rtl-sdr/tree/src/rtl_sdr.c#n236
Regards, Vasil
Hi Pete,
On 01/06/2019 05.00, P C wrote:
Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. I was hoping for something like, The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......).
Would you know where can find that kind of information?
Sorry, I don't know.
In my opinion smaller buffer sizes would remove latency as the buffer would fill faster and rtlsdr_read_sync would returns sooner but this would add an additional overhead as rtlsdr_read_sync would be called more often, and bigger buffer sizes would add latency but remove the overhead.
Hope this helps.
Regards, Vasil
Vasil,
Nothing to be sorry for. You give me a lead to follow. I'm not using synchronous mode but maybe I should. The last time I did anything with PLLs was the Signetics NE5xx family. Ouch, that dates me.
Thanks Pete
On 6/1/2019 10:38 AM, Vasil Velichkov wrote:
Hi Pete,
On 01/06/2019 05.00, P C wrote:
Unfortunately, had already found that page.?? Maybe I am dense as a box of rocks but I couldn't find what I was looking for there. I was hoping for something like, The size of the buffer is used while capturing in synchronous mode.?? It is adjustable so that (insert the reason here).?? Make it larger if (insert reason here) but that will cause (insert result here).?? (more explanation......).
Would you know where can find that kind of information?
Sorry, I don't know.
In my opinion smaller buffer sizes would remove latency as the buffer would fill faster and rtlsdr_read_sync would returns sooner but this would add an additional overhead as rtlsdr_read_sync would be called more often, and bigger buffer sizes would add latency but remove the overhead.
Hope this helps.
Regards, Vasil
-
P C -
Vasil Velichkov