Why is my MATLAB video such poor quality?

Here's an imgur link to the poor quality video of someone walking: https://imgur.com/a/mr4340L . Other videos I've rendered have turned out fine, see here for a good quality video: https://imgur.com/a/2Xlnb9M

Notice how in the bad quality video, the feet outlines (an image plotted with Image Processing Toolbox) and the line on the ground are blurry, and the dots on the person also lack definition. Is this a rendering issue of some sort? I have tried doing

set(fig, 'Renderer', 'zbuffer');

as well as not specifying any renderer. I'm on M1 Mac running MacOS Sonoma 14.6.1.

[William Rose]

@Mitchell Tillman, the first link leads to a message "The requested page could not be found.". The link to the second video works. Since you created both videos, tell us what you did differently, if anything.

[Walter Roberson]

@William Rose

The first link accidentally extended to include the period following. I have editted the link and it works now

[Mitchell Tillman]

Thank you for fixing the link. I’m really not sure what if anything I may have done differently. They both used the same code to plot, and that code reads from config files that only differ slightly. I’ve been switching back and forth between using the command line and plotting with the GUI, could that be it?

Answer 1

[William Rose]

@Walter Roberson, thank you for the link fix.

[Edit: fix spelling.]

@Mitchell Tillman, I would definitely explore the possibility that the quality difference is due to GUI versus command line. I would also compute the file size divided by the number of frames, to get average bytes per frame, for the two videos. It looks like the lower quality video is more compressed. A lower number of bytes per frame, in the low quality video, would support that hypothesis. Then you would investigate whether there is some setting for image compression that is different in the two cases.

The walking pace is about 215 frames per full stride in the lower quality video, and about 295 frames per stride in the higher quality video, i.e. ~35% faster pace in the low quality video, assuming frame rate is constant. (Average across 5 strides, in both cases.) But that does not explain the quality difference.