nvenc SDK example question

I am trying to run the NVENC encoder SDK examples which are able to provide hardware accelerated video encoding.

I am trying to run the nvencoder sample with the dataset I found here: http://www.sunrayimage.com/download/image_examples/yuv420/tulips_yuv420_inter_planar_qcif.yuv

I ran it with the following command line on windows:

NvEncoder.exe -i tulips_yuv420_inter_planar_qcif.yuv -o test.mp4 -size 176 144

The resulting file that is produced cannot really be played by any media player. VLC sort of loads it but does not produce any image that I was expecting.

Looking at the help message, it says:

-o <string>                  Specify output bitstream file

I wonder if something else has to be done to make sure this file is playable or perhaps I am not using this example correctly? Maybe the bitstream file is not a valid H.264 encoded file?

I have been struggling all day trying to figure this out. Would love some help!

Many thanks!