问题
I'm developing on Processing 2.0b, and i just bought a C920 logitech webam for a good capture quality.
Then I try to capture at 1920 x 1080, the problem is that I'm under 15 fps per seconds..
When I list all the devices availsable to capture, the program write:
Some size and fps
...
-[61] "name=HD Pro Webcam C920,size=1024x576,fps=5"
-[62] "name=HD Pro Webcam C920,size=1024x576,fps=30"
-[63] "name=HD Pro Webcam C920,size=1280x720,fps=5"
-[64] "name=HD Pro Webcam C920,size=1280x720,fps=30"
-[65] "name=HD Pro Webcam C920,size=1600x896,fps=5"
-[66] "name=HD Pro Webcam C920,size=1600x896,fps=30"
-[67] "name=HD Pro Webcam C920,size=1920x1080,fps=5"
-[68] "name=HD Pro Webcam C920,size=1920x1080,fps=30"
...
some others size and fps...
So, as I can read.. for the size 1920 x 1080 the framerate of 30 fps is available..
What's wrong ??
Even if I force the program or run at 30 fps.. theres a crash pointing on cam.start(); telling me that the framerate for this size isn't available...
Any help ... ?
回答1:
I ran into this problem a few months back as well. Here's what I found, searching through forums and contacting customer support:
The Logitech C920 only provides 30fps at 1080p with applications that supports H.264 directly, and can pull in the H.264 stream directly from the camera. The C920 does on-board H.264 compression, but most applications don't support pulling the compressed stream straight from the camera; instead, they have to decompress then re-compress the stream, dropping the framerate.
Skype supports H.264 straight from the camera, so with Skype you should be able to get 1920x1080 @ 30fps, but you won't see this high framerate with Processing. Also, I think you have to use Windows to use the Logitech drivers to support this.
I'll post the research I did a while back if I can find it, but unfortunately the answer is that you'll have to drop either your resolution or your framerate.
来源：https://stackoverflow.com/questions/13113560/processing-c920-logitech-capture-frame-rate-video-discourse