the control of bitrate

[china_y_]

as i know the intel media  sdk can control the bitrate

so i set the parameter as follow  expect  to get a bitrate as small as possible

m_EncParam.mfx.TargetUsage = MFX_TARGETUSAGE_BALANCED ;
m_EncParam.mfx.TargetKbps = 512  ;
m_EncParam.mfx.RateControlMethod = MFX_RATECONTROL_VBR ;
m_EncParam.mfx.MaxKbps = 512  ;

i set the ratecontrol method  MFX_RATECONTROL_VBR 

but the bitrate is much bigger than i expected

so  i compare the media sdk with x264 t

x264 get i a much smaller bitrate

is something wrong with my settings 

 or i forgot some key setting 

thank you advanced 

best wishes 

[Petter_L_Intel]

Hi,

Can you please provide some more details about your encoder configuration? The easiest way to capture complete configuration is to collect a Media SDK trace log (the tracing tool is located in the SDK tools folder).

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".

Regards,
Petter