I've been digging into the GH1 firmware code and found that overall bitrate appears to have a big effect on the maximum speed that flash memory writes can occur. I’ve always wondered why the write speed error comes up in AVCHD mode when clearly the data rates are well below what the card can handle. I think I found the answer.
When the write speed error comes up it’s because the calculated maximum write rate has been exceeded – whether the card can handle more or not. I tried the Lpowell settings but changed two things: I doubled the overall bitrate to 86,000,000 and I checked Native 24p. Upping the overall bitrate nearly doubled the calculated flash write rate (i.e. the fastest write rate the camera attempts to write to flash). It appears to be working! I’m not getting any lockups and the clips look great. I tested this with highly detailed scenes, fast shutter speeds, everything I normally do to break the codec and it seems to be standing up.
We probably need to do some fine tuning and more testing (hint, hint, Lpowell), but so far it’s looking pretty good. I ran my tests with a Transcend class 10 card.
Chris
When the write speed error comes up it’s because the calculated maximum write rate has been exceeded – whether the card can handle more or not. I tried the Lpowell settings but changed two things: I doubled the overall bitrate to 86,000,000 and I checked Native 24p. Upping the overall bitrate nearly doubled the calculated flash write rate (i.e. the fastest write rate the camera attempts to write to flash). It appears to be working! I’m not getting any lockups and the clips look great. I tested this with highly detailed scenes, fast shutter speeds, everything I normally do to break the codec and it seems to be standing up.
We probably need to do some fine tuning and more testing (hint, hint, Lpowell), but so far it’s looking pretty good. I ran my tests with a Transcend class 10 card.
Chris
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