non-monotonous decodetimestamp

[wang_y_1]

sInputParams(from intel media sdk sample) struct value is :

nTargetUsage    4
CodecId    541283905
ColorFormat    842094169
nPicStruct    1
nWidth    1920
nHeight    1080
dFrameRate    30
nNumFrames    0
nBitRate    3757
MVC_flags    0
nGopPicSize    0
nGopRefDist    0
nNumRefFrame    0
nBRefType    1
nIdrInterval    0
nQuality    0
numViews    1
nDstWidth    1920
nDstHeight    1080
memType    0
bUseHWLib    1
strSrcFile    ../IntelCodecTest/1920X1080_i420.yuv
pluginParams.pluginGuid    
pluginParams.strPluginPath    
pluginParams.type    0
.srcFileBuff.size()    0
dstFileBuff.size()    1
HEVCPluginVersion    0
nRotationAngle    
strPluginDLLPath    libsample_rotate_plugin.so
nAsyncDepth    4
gpuCopy    0
nRateControlMethod    1
nLADepth    0
nMaxSliceSize    0
nQPI    0
nQPP    0
nQPB    0
nNumSlice    0
UseRegionEncode    0

may be use full info:

libva info: VA-API version 0.99.0
libva info: va_getDriverName() returns 0
libva info: User requested driver 'iHD'
libva info: Trying to open /opt/intel/mediasdk/lib64/iHD_drv_video.so
libva info: Found init function __vaDriverInit_0_32
libva info: va_openDriver() returns 0
isV4L2InputEnabled    0Encoding Sample Version 1.0.0.0

Input file format    YUV420
Output video        AVC
Source picture:
    Resolution    1920x1088
    Crop X,Y,W,H    0,0,1920,1080
Destination picture:
    Resolution    1920x1088
    Crop X,Y,W,H    0,0,1920,1080
Frame rate    30.00
Bit rate(Kbps)    3757
Gop size    0
Ref dist    0
Ref number    1
Idr Interval    0
Target usage    balanced
Memory type    system
Media SDK impl        hw
Media SDK version    1.19

key code:

        // at this point surface for encoder contains either a frame from file or a frame processed by vpp
        sts = m_pmfxENC->EncodeFrameAsync(NULL, &m_pEncSurfaces[nEncSurfIdx], &pCurrentTask->mfxBS, &pCurrentTask->EncSyncP);

input timestamp is : 90K*1, 90K*2, 90k*3, ... and so on

output timestamp and decodetimestamp is :

isK 1    timeStamp: 90000    decodetimeStamp: 87000
isK 0    timeStamp: 360000    decodetimeStamp: 351000
isK 0    timeStamp: 180000    decodetimeStamp: 180000
isK 0    timeStamp: 270000    decodetimeStamp: 270000
isK 0    timeStamp: 630000    decodetimeStamp: 621000
isK 0    timeStamp: 450000    decodetimeStamp: 450000
isK 0    timeStamp: 540000    decodetimeStamp: 540000
isK 0    timeStamp: 900000    decodetimeStamp: 891000
isK 0    timeStamp: 720000    decodetimeStamp: 720000
isK 0    timeStamp: 810000    decodetimeStamp: 810000
isK 0    timeStamp: 1170000    decodetimeStamp: 1161000
isK 0    timeStamp: 990000    decodetimeStamp: 990000
isK 0    timeStamp: 1080000    decodetimeStamp: 1080000
isK 0    timeStamp: 1440000    decodetimeStamp: 1431000
isK 0    timeStamp: 1260000    decodetimeStamp: 1260000
isK 0    timeStamp: 1350000    decodetimeStamp: 1350000
isK 0    timeStamp: 1710000    decodetimeStamp: 1701000
isK 0    timeStamp: 1530000    decodetimeStamp: 1530000
isK 0    timeStamp: 1620000    decodetimeStamp: 1620000
isK 0    timeStamp: 1980000    decodetimeStamp: 1971000
isK 0    timeStamp: 1800000    decodetimeStamp: 1800000
isK 0    timeStamp: 1890000    decodetimeStamp: 1890000
isK 0    timeStamp: 2250000    decodetimeStamp: 2241000
isK 0    timeStamp: 2070000    decodetimeStamp: 2070000
isK 0    timeStamp: 2160000    decodetimeStamp: 2160000

i don't know how to solve it .please help me.

thanks any advise.

os: centos 7.2

software version: 2017