I have an implemenation of your h264 SW and QSV encoders. For VBR rate control method, I expose the TargetKpps and the MaxKbps parameters but I am wondring if you have a "Minimum bitrate"?

The only thing I see concerning the minimum bitrate is the following you post here http://software.intel.com/en-us/forums/topic/404650

"Also, by default, Media SDK limits the compression ratio to 500x. So if you're trying to encode frames with resolution 1920x1080, then the default minimum bit rate is ~1500kbps, even if you set the rate to 500kbps. If you do not want to the SDK to impose this restriction, then please set the mfxExtCodingOption2.BitrateLimit parameter to "OFF"."



FYI my setup:

Intel Media SDK System Analyzer (64 bit)
The following versions of Media SDK API are supported by platform/driver:

Version Target Supported Dec Enc
1.0 HW Yes X X
1.0 SW Yes X X
1.1 HW Yes X X
1.1 SW Yes X X
1.3 HW Yes X X
1.3 SW Yes X X
1.4 HW Yes X X
1.4 SW Yes X X
1.5 HW Yes X X
1.5 SW Yes X X
1.6 HW Yes X X
1.6 SW Yes X X
1.7 HW Yes X X
1.7 SW Yes X X
1.8 HW No
1.8 SW Yes X X

Graphics Devices:
Name Version State
Intel(R) HD Graphics 4000 Active
NVIDIA GeForce GT 545 Active

System info:
CPU: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz
OS: Microsoft Windows 8 Enterprise
Arch: 64-bit