Forum Post: dec framerate can not to 60fps

hi all,now i do a test for the 8168 dec ,i read 2 h264 file to dec ,

while (1)
{
unsigned char* pt = streamBuf + 4;
unsigned char* pNal = streamBuf;
while (pt - streamBuf < size && m_running)
{
if (pt[0] == 0 && pt[1] == 0 && pt[2] == 0 && pt[3] == 1)
{
int nalSize = pt - pNal;
#if 1
ITCM_decPutBuffer(chId,pNal,nalSize);
#endif
pNal = pt;
pt += 4;
OSA_waitMsecs(17);
}
else
{
pt++;
}
}
}

but i found that will can not be decoded ,just the wait time is 19ms that can be decoded. so why?

19ms that means just about 53 fps,can not be to 60fps?

then i do a loopback+dec file test,just 1 enc ch+2 dec,i found that that dec file channel just can be 50fps,the loopback can be 60fps

that following is my configure

static SystemVideo_Ivahd2ChMap_Tbl systemVid_encDecIvaChMapTbl =
{
.isPopulated = 1,
.ivaMap[0] =
{
.EncNumCh = 1,
.EncChList = {0},
.DecNumCh = 0,
.DecChList = { 0},
},
.ivaMap[1] =
{
.EncNumCh = 1,
.EncChList = {1},
.DecNumCh = 1,
.DecChList = {1},
},
.ivaMap[2] =
{
.EncNumCh = 0,
.EncChList = {0},
.DecNumCh = 1,
.DecChList = {0},
},

};