VIDEOENCODER_BITRATE_MODE - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// ksmedia.h
typedef enum {
ConstantBitRate,
VariableBitRateAverage,
VariableBitRatePeak
} VIDEOENCODER_BITRATE_MODE;
View the official Windows Driver Kit DDI referenceNo description available.
The VIDEOENCODER_BITRATE_MODE enumeration describes the bit rate encoding modes supported by the device.
ConstantBitRateSpecifies that the encoding bit rate is constant.
VariableBitRateAverageSpecifies that the encoding bit rate is variable, with the specified bit rate used as a guaranteed average over a specified window. The default window size is considered to be 5 minutes. That is, this guarantees that the average bit rate over the window period (5 minutes) will not exceed that specified in ENCAPIPARAM_BITRATE.
VariableBitRatePeakSpecifies that the encoding bit rate is variable with the specified bit rate used as an average with a peak not to exceed the specified peak bit rate over a specified window. The default window size is considered to be 500ms (classically one GOP). That is, this bit rate is "constant quality" − the bit rate is expected to average around ENCAPIPARAM_BITRATE but may spike above this. It cannot exceed the bit rate specified in ENCAPIPARAM_PEAK_BITRATE.
For all three modes, ENCAPIPARAM_BITRATE must be set to the expected average bit rate over a 5 minute period.
When VariableBitRatePeak mode is used, the ENCAPIPARAM_PEAK_BITRATE must also be set to the peak bit rate, which the VBR encoder must not exceed over a 500ms period (typically one GOP for MPEG-2 video).