Quote from: wildew on September 22, 2012, 08:19:31 PM
... OH, and for another future reference on video files.
winff is OK but the real deal is ffmpeg - it is a command line tool but there's a windows build that will convert ANYTHING - Quickly. Fair learning curve but tons of support out there. Another good tool if the cam is DVD friendly is DVDcatalyst. Love it for putting movies on my "phone" and for video conversions.

WinFF is the GUI for ffmpeg, and there are versions for Linux and Windows systems.

Quote from: see3d on September 22, 2012, 08:20:58 PM
TK,  Your method to calculate the lift is valid.  My method to calculate the lift is valid.  They generate the same answer.  I stand by my statements 100%.  First, for the battleship floating in a bucket of water.  Take every square inch of the hull and calculate the PSI at the average water depth for that square inch.  Add all the square inches up and guess what?  The total force lifting the battleship is equal to the weight of the ship.  The weight of the "virtual water" displaced is also the same number. A=1, B=1, A=B.

Let's take a very simple example.  Take a 1 inch cube with a total weight the tiniest bit less than a cubic inch of water.  It will float, but right at the surface.  It will have a virtual water displacement of 1 cubic inch of water weighing 0.036 pounds.  The pressure at the bottom surface one inch deep is 0.036 PSI.  The lift from the pressure differential is 0.036 pounds.  It does not matter if we calculate it with displaced virtual water or pressures at the water depth.  The answer is still the same.    The pressures at depth is the truest mathematical representation.  The buoyancy in virtual water is a geometric equivalent IMHO. 

If you want to argue with this analysis, then please do it with an actual example with real numbers.

How about if I just use your numbers as they stand and point out that a pressure differential is not the same thing as a pressure? You can take your one cubic inch down to a mile of depth, and the _pressure in psi due to depth_ will be much greater. The buoyant force will be just the same though, since the pressure differential across the vertical height of the cube is still the same.... since the pressure of water increases _linearly_ with depth. Just like the pressure of air increases linearly with decrease in volume.

If you are just using the pressure differential rather than the "psi due to depth" which is an absolute pressure, then fine, I suppose I am in agreement with your usage. But really..... your terminology was misleading.

Quote from: mondrasek on September 22, 2012, 06:20:22 PM

NOW you tell me!

Thanks for the info.  I'll have to check that out if I have to do this again.

What format does your video camera record in native?  I think mine is like AC3 or some such.  NOT PC friendly at ALL!

YouTube says only 13 minutes to go!  I wonder if that is realistic or just computereez for STFU and have a sandwich...

M.

The time remaining can vary due to internet traffic and the phase of the moon.
My camera is a Panasonic, it records its HD video files with a .MOD extension, and splits off some info into another tiny file that I don't bother with. My Linux system "thinks" that .MOD belongs to Amiga SoundTracker files (audio) but when I doubleclick on the file it opens and plays in MoviePlayer just fine... but at the wrong aspect ratio, so I have to manually set the aspect ratio to 16:9 in the player.  For the right icon to show up with the file and for it to be recognised by other players I just change the extension to .mpg or .mp4, but the aspect ratio still must be set manually. After I run them through WinFF (ffmpeg gui) I set the aspect ratio in WinFF and the output .avi file is then correct aspect ratio.
I see .ac3 is on the list of formats that WinFF supports.

OK - I have a minute

Quotea pressure differential is not the same thing as a pressure

Relativity...  what CAN be measured as anything other than a difference?

Quote from: TinselKoala on September 22, 2012, 09:28:15 PM
If you are just using the pressure differential rather than the "psi due to depth" which is an absolute pressure, then fine, I suppose I am in agreement with your usage. But really..... your terminology was misleading.

I welcome correction if my terminology is misleading (as opposed to just imprecise).  I used the absolute PSI in my statement because the top of the Riser is above the water.  Also, the air pocket pressure adds to the PSI of the water depth, so it can have some positive or negative additive "virtual" water head.  Much easier to calculate with pressures than figuring out an equivalent geometry.

I am still learning about the ZED.