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Chroma Subsampling	YUV subsampling
1×1	4:4:4
1×2	-
2×1	4:2:2
2×2	4:2:0

YUV subsampling 4:2:2, 4:2:0 當中又有不同的取法。比chroma-subsamplingf 複雜。
Reference: impulseadventure

UPnP Intel builder Send Variable update

every state variables of UPnP AVT RCS should be updated to CP by through of LastChange variable 56
every state variables of UPnP AVT RCS should be updated to CP by through of LastChange variable.
the variable (LastChange) should be well formated as <Event ……> </Event>
the codes are as following:

void UPnPFireLastChangeEvent(UPnPMicroStackToken upnptoken, char * service_name, char *var_name, char* val)
{
char *tmpXML = (char *) malloc(strlen(service_name) + strlen(val) + strlen(var_name) + 103 + 20) ;
char *eventXML = NULL;

sprintf( tmpXML , “<Event xmlns=\"urn:schemas-upnp-org:metadata-1-0/%s/\">"
“<InstanceID val=\"0\">"
“<%s val=\"%s\"/>"
“</InstanceID></Event>", service_name,var_name,val);

eventXML = (char*)malloc(ILibXmlEscapeLength(tmpXML)+1);
if ( tmpXML == NULL || eventXML == NULL)
return;

ILibXmlEscape(eventXML,tmpXML);

if ( ! strncmp(“AVT",service_name,3) )
{
UPnPSetState_AVTransport_LastChange(UPnPmicroStack, eventXML);
}
else if ( ! strncmp(“RCS",service_name,3) )
{
UPnPSetState_RenderingControl_LastChange(UPnPmicroStack, eventXML);
}
else
{
fprintf(stderr,"%s %d: Service Nmae should be \"AVT\" or \"RCS\"\n",__FILE__,__LINE__);
}

if ( eventXML) free (eventXML);
if ( tmpXML ) free ( tmpXML);
}

CTorrent reference

a crazy guy document CTorrent.
yaoxuchen’s blog