A function that will be called from gst_buffer_list_foreach(). The buffer
field will point to a the reference of the buffer at idx in group.
When this function returns #GST_BUFFER_LIST_CONTINUE, the next buffer will be
returned. When #GST_BUFFER_LIST_SKIP_GROUP is returned, all remaining buffers
in the current group will be skipped and the first buffer of the next group
is returned (if any). When GST_BUFFER_LIST_END is returned,
gst_buffer_list_foreach() will return.
When buffer is set to NULL, the item will be removed from the bufferlist.
When buffer has been made writable, the new buffer reference can be assigned
to buffer. This function is responsible for unreffing the old buffer when
removing or modifying.
A function that will be called from gst_buffer_list_foreach(). The
bufferfield will point to a the reference of the buffer atidxingroup. When this function returns #GST_BUFFER_LIST_CONTINUE, the next buffer will be returned. When #GST_BUFFER_LIST_SKIP_GROUP is returned, all remaining buffers in the current group will be skipped and the first buffer of the next group is returned (if any). When GST_BUFFER_LIST_END is returned, gst_buffer_list_foreach() will return. Whenbufferis set to NULL, the item will be removed from the bufferlist. Whenbufferhas been made writable, the new buffer reference can be assigned tobuffer. This function is responsible for unreffing the old buffer when removing or modifying.