Where can I find converting decoded YUV to XBGR32 or ABGR32?
NvVideoConverter is an initial implementation and it is a bit complex to use it. We now has NvBuffer APIs and would suggest use NvBufferTransform(). Both interfaces utilize same hardware engine.
Is it possible to specify the output format in XBGR32 or ABGR32 format through NvBufferTransform() function?
Yes. Your source buffer is in NvBufferColorFormat_NV12 and you can allocate destination buffer in NvBufferColorFormat_ABGR32. And call NvbufferTransform() to get destination buffer in ABGR32.