View Full Version : Same drive, build, settings-Different media consumption
Kevin Wild
02-19-2010, 06:55 PM
Anyone have any ideas on this?
We've done a bunch of 2 camera shoots this week...all the same build (21, I believe) and the cameras had identical settings. Both were using RED Prime Pro lenses...one was a wide shot, one was a closeup.
We started with the same amount of storage space/time left, but at one point, they were nearly 10% off from each other, though they were starting/stopping at the same exact time.
Something amiss?
Kevin
Martin Weiss
02-19-2010, 07:18 PM
R3D has a variable compression rate, thus the differences.
I also remember someone posting tests where it turned out that completely black pictures turned out to have the highest data rate.
Kevin Wild
02-19-2010, 08:05 PM
Hmm...I knew the codec was variable, but still...pretty big difference when they were shooting nearly the same thing under same lighting conditions. I hope that's all it is.
Thanks!
Kevin
Brook Willard
02-19-2010, 08:30 PM
A wide shot [more detail, more depth of field] will often have a higher data rate than a close-up [less depth of field, less detail].
Charles Angus
02-20-2010, 05:20 AM
R3D has a variable compression rate, thus the differences.
I also remember someone posting tests where it turned out that completely black pictures turned out to have the highest data rate.
Weird.
Although I remember some (and only some) of our Shake's at work would read-in and render fully black TGA's VERY slowly. Normal frames with detail were fine.
Sorry to get off topic...
Harry Clark
02-20-2010, 05:39 AM
And you may notice that, if you play back whatever proxy size your computer can play at "normal" speed (24/ 25 fps), or one size larger if it can play close to normal, the effect of variable bitrate recording on motion playback.
For instance, if you have a lock off with lots of detail, whatever IS moving in the frame (actor) stutters a bit, but if you pan quickly the motion is completely smooth.
The original footage is perfect, of course, but the bitrate going up on the scene with higher detail means that your playback program (Quicktime) needs to drop the frame rate to accommodate the bigger data flow. A mostly motion blurred pan can still play at 24 fps (or whatever your base frame rate is)
You can also do a test shot with detail and motion. Defocus the lens and snap it in to sharps, then play it back on the computer.
Just an interesting effect... I think the Red Team was very smart to use a variable bitrate.
Cheers,
Harry