Buffer Offload Fine-tuning

Started by theollybanks, June 03, 2013, 02:17:38 AM

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theollybanks

So I'm no expert in any of this, my knowledge of hardware and firmware is worryingly limited but here's what I'm seeing:

When the lv_rec and eventually raw_rec modules were created they offloaded chunks of this RAW data to the CF card in chunks of 32mb, which for the faster data rates of CF was, and is entirely fine, however on SD cards with older models like the 60D, 550D etc the maximum speed of the controller is 20mb/s or there about's, so from my purely layman-esqe and uneducated perspective, could we theoretically get a higher record time and possibly even higher resolutions by lowering the chunk sizes for the slower SD cameras and thus allow the buffer to offload these smaller chunks quicker freeing space for indefinite or extended recording?

So for example (not at all tested or correct) if it takes a 60D 5 seconds to offload one of these chunks of 32mb to the SD, surely it would take it considerably less time to offload a 16mb chunk? obviously we would still use the entire buffer's storage but rather than say 6 chunks of 32mb's we use 12 chunks of 16mb's and try to attain a quicker offload speed?

Anyway just my thoughts on the matter as a longtime lurker and long time magic lantern user with my 60D of truth!

- Olly

1%

You can't pick the chunk sizes.


theollybanks

Thanks for clearing up up guys!