What is std_1U4S4U_X02

what is std_1U4S4U_X02\ std_4U4S4U_X04\ std_2U4S4U_X08, when i call nvjpeg apis, it will call std_1U4S4U_X02 in A serial card. I want to know Why nvjpeg API call std_1U4S4U_X02, and what std_1U4S4U_X02 is

Hello @yaoge,

can you be a bit more specific why you need this information and most of all, why you singled out this specific identifier?

Those identifiers are in libnvcuvid and I am pretty certain they are not publicly accessible.


@MarkusHoHo when I ran nvJPEG_encoder on A100 using LD_DEBUG=libs, I found libnvcuvid.so.1 was called. But nvJPEG_encoder.cpp does not call any nvcuvid API, curious about that. Finally found that __std_1U4S4U_X02 was called. So I wonder why and how this API is called.

These are internal symbols to libnvcuvid with respect to scaling and chroma subsampling. When you use nvjpeg encoding there will be implicit calls to libnvcuvid since the GPU backend will use CUDA.
Beyond that there is really nothing more to share about this.


hello, @MarkusHoHo thanks for your detailed reply.
There is another question, these symbols were not called in T4, only called in A30 or A100(in my env). Do you know why it is not called in T4?

That I do not know, but my guess would be some innovative architectural updates in terms of both Hardware support and Software design.

@MarkusHoHo thanks for your answers.