__preview_get_format
*fmt = *__preview_get_format(prev, sd_state, PREV_PAD_SINK,
format = __preview_get_format(prev, sd_state, PREV_PAD_SINK,
format = __preview_get_format(prev, sd_state, PREV_PAD_SINK,
format = __preview_get_format(prev, sd_state, PREV_PAD_SOURCE,
format = __preview_get_format(prev, sd_state, fmt->pad, fmt->which);
format = __preview_get_format(prev, sd_state, fmt->pad, fmt->which);
format = __preview_get_format(prev, sd_state, PREV_PAD_SOURCE,