Buffers and crashes

[Gavin Greenwalt]

The SI DVR movie reminded me a few questions I had.

How large is the oncamera cache? I'm assuming you guys have some built in RAM for buffering. 256MB? Does it buffer the REDCode or the uncompressed RAW stream? I know hard drives like to get data in bursts and can see significantly higher performance than streaming... would it be possible to record very short uncompressed bursts to hard drive using the cache as a framestore?

What happens if the camera crashes during a take. What happens to the Quicktime Mov? Is it corrupted?

 

[Jochen Schmidt-Hambrock]

In audio there are systems that loose the take when crashing and systems where everything´s saved untill the moment of the crash.

Somebody explained it to me a couple of years ago (hope I remember correctly) that some systems write a file to disk the moment you hit the red button that has the maximum specified recording time. Then it just modifies that file. So a crash is not deadly for already recorded data.
Other systems start writing the file and if a crash occurs, the whole file is lost.
Because the file was not done being created (my english is in its outer limits).

Did this make sense? Maybe the technology has advanced (also I havent had a recording crash in years).

Jochen

 

[Rob Lohman]

The QuickTime files are just references to the actual data files. So don't worry about them.

There will be ways to deal with corrupt or files that have not been closed properly. The latter should in general load fine but the last frame might be corrupt.

In theory you could corrupt the file system when power is lost for example that could screw things up. Always good to format your drive if you had a power drop or if the camera should crash. That way you know for sure you're good to go shoot new stuff.

 

[Steve Freebairn]

Rob, will the camera be able to format a drive without use of a computer?

 

[Obin Olson]

ya will it Rob? that is a good q

Can the camera deal with disks like any machine can - format - transfer -copy etc?

 

[antique suede]

The SI DVR movie reminded me a few questions I had.

How large is the oncamera cache? I'm assuming you guys have some built in RAM for buffering. 256MB? Does it buffer the REDCode or the uncompressed RAW stream? I know hard drives like to get data in bursts and can see significantly higher performance than streaming... would it be possible to record very short uncompressed bursts to hard drive using the cache as a framestore?
QUOTE]

Sorry,but there is no one who answers these questions from thatoneguy.
So if there is anyone who can tell me or us the answer, i will be lucky.
Thanks

 

[Rocco Schult]

ok, I have no clue of the onboard cache (surely it must have, but its size?).
But I wouldn't count or make anything dependent on its size - it has a specified purpose, to cache the data for the record and packing the data in its whatever wrapper, or so, not doing additional work. And thus, onboard chache is usually comparibly small if I'm not wrong.

 

[Rob Lohman]

There is an onboard buffer. Yes, format on the camera