I am callingMFXVideoDECODE_DecodeHeader in an attempt to initialize the mfxVideoParam structure. The source of the H.264 encoded data is in the following file (http://software.intel.com/file/m/42421) which was generated using the Intel Media SDK (version 1.3). The sequence and picture parameter sets are contained in the first 46 bytes of the file.
If I provide the first 50 or 75 bytes fromthis file to the MFXVideoDECODE_DecodeHeader function (via the mfxBitStream parameter), the function returns MFX_ERR_NONE and the mfxVideoParam structure is filled out correctly. If I provide a different number of bytes (e.g. 46, 47, 48, 49, 70, 71, 72, 73, 74), the function returns MFX_ERR_MORE_DATA.
I expected to be able to provide only the first 46 bytes. Can anyone explain to me why this does not work?