The pjmedia_frame_ext is used to carry a more complex audio frames than the typical PCM audio frames, and it is signaled by setting the "type" field of a pjmedia_frame to PJMEDIA_FRAME_TYPE_EXTENDED. With this set, application may typecast pjmedia_frame to pjmedia_frame_ext.
This structure may contain more than one audio frames, which subsequently will be called subframes in this structure. The subframes section immediately follows the end of this structure, and each subframe is represented by pjmedia_frame_ext_subframe structure. Every next subframe immediately follows the previous subframe, and all subframes are byte-aligned although its payload may not be byte-aligned.