It is possible to specify multiple flag2 and partitions params, as below. Please make sure there are no spaces within the elements.
<format> <output>mp4 </output> <video_codec>libx264 </video_codec> <video_codec_parameters> <flag2>+bpyramid+wpred+mixed_refs+dct8x8-fastpskip</flag2> <partitions >+parti8x8+parti4x4+partp8x8+partb8x8</partitions> </video_codec_parameters> </format>
Please be aware that this is a high profile function that will not be supported in devices that require main profile.