I am seeing some weird results using omxh264enc. From a previous post i learned the following for the rate control (control-rate) options of the nvidia encoder:
Disabled: constant QP
Variable and Variable-skip-frame: actually it is same, for bSkipframe is not handled in codec driver.
Constant and constant-skip-frame: actually it is same, for bSkipframe is not handled in codec driver.
Pardon my ignorance and let me know if i am simply mistaken, but if “Disabled” is selected that basically means a constant quality based on the cooefficent defined in qp-range or enctune.conf. Hence the bitrate should vary greatly depending on the amount of motion on the screen since quality is the defining value. So in theory the “bitrate” option shouldn’t even be relevant since the output data rate is defined by quality.
Yet when I set the rate control to “Disabled” i am getting almost a perfectly restricted output data rate defined by the “bitrate” parameter.
I’ve always had issues with CBR not restricting the data to set bitrate option and it is looking like “Disabled” produces a way better restriction to bitrate.
Any ideas what is going on? Is there any better documentation on the rate control options?