Video Mystery

Every few years or so I will circle back and try to understand video.  Then I give up.

I still use my D7000 for video capture.  It can shoot at 1080p at 24fps or 720p at 30fps.  Now your experience maybe different from mine.  If I were to shoot static scenes then I guess it doesn't make any difference.  But if I were to shoot cycling on the velodrome, I find the footage has too much shudder or stutter.  The stutter is subtle and has nothing to do the playing machine or software being not optimized or being inferior to play video full HD.  I think the shudder has to do with the capture the way it's recorded in the D7000.  I think at 1080p and 24fps the shudder is pretty insufferable for action shots.  At 720p and 30fps, it seems like it's better, the motion is a bit smoother.

I set shutter at 1/50s for 24fps and 1/60s for 30fps.

Again this whole write up is not scientific or anything.

I think about bit rate and I read the D7000 captures at 20mbps and I guess it's not very good if you want to grade your video in post or when the scene is dark or when you are shooting moving subjects, that's the frame is quite different from each other.

Lucky me, D7000 can be hacked to increase the bit rate to some ~64mbps,  I proceeded to downgrade the firmware to 1.03 and patch it from the Nikon hackers.  The thing is I don't know what I lose by downgrading the firmware--probably lost the lens data from jpeg correction and I don't know what I gain on my video--other than the file would be bigger and I can't even play back the high bit rate video on the camera.

So I am able to shoot at 1080p at 24fps and at higher bit rate like 64mbps.

I am able to play the footage on my MBP but I don't think I see any noticeable improvement on how smooth the action become, like when a cyclist goes by.  Perhaps there is some but I really can't tell for sure.

When the video is shot with the the Optex 1.33 anamorphic adapter, then I use Handbrake to de-squeeze it so it can play at 2554 x 1080.  Then I notice when after the desqueeze the bit rate goes to 1 or 2 mbps no matter what my footage bit rate was.  I read somewhat about it but I could not fully understand it, well that's expected.  I think if the scenes or frames have a lot of changes then the bit rate would rise to capture the changes otherwise there is really no need to increase the bit rate.  Again I don't see any significant degrading in the video in particular motion scenes.

Now the raw footage is desqueezed then I proceed to use iMovie to whip up some project and use share to create a new high quality video like with titles and sound track.

And surprise, even with the above 1 or 2 mbps footage the final video can have a bit rate more than that.  So I am perplexed.  I thought you can't have what you don't have to begin with.  If the footage is only 1.2mbps how could the final video has a bit rate in the 10.

D7000 file.MOV at 1080p 24fps 64mbps -->Handbrake --> file.mp4 1080p 24fps 1.5mbps   ---> iMovie file.mp4 1080p 24fps 10mbps

What I want is just smooth action video.  Why so hard with D7000?

Again video is a major mystery to me.