I did the conversion on a Windows host. You can download the precompiled Windows binaries of QEMU, provided by Prashant Satish, or those provided by Eric Lassauge.
The procedure is the same in Linux hosts.
- To convert VirtualBox virtual appliance to a VMDK file.
qemu-img convert virtualbox.vdi -O vmdk vmware.vmdk
- If you have VMWare Workstation or more luxury version, you can start with creating a new virtual machine. During the process, you have the option of selecting an "existing disk". In this case, you simply select the .vmdk file.
However, I would like to stick to the free VMWare Player that does not provide the option of selecting an "existing disk". I have to use a workaround.
Start VMWare Player, then create a new virtual machine, for instance, a virtual machine called "vboxvmware". You must select "I will install the operating system later." option as the two images show.
Since you created or downloaded the VirtualBox virtual machine, you should know what guest operating system it is and what memory capacity is allocated. Choose them accordingly.
Next step, choose the option of "Store Virtual Disk as a Single File".
Upon confirming your choice, you will see that the virtual machine is created.
The last step is to edit the VMWare virtual machine configuration file (.vmx file). Go to the directory where the virtual machine is located, locate the .vmx file, and edit the file using your favorite text editor. In the editor, locate the line of "scsi0:0.fileName = ..." and replace the virtual disk file by the .vmdk file previously converted using QEMU. Note that when you edit the file, make sure the path of the .vmdk file is correct if it is not copied to the directory. Then, you can safely remove the vboxvwmare.vmdk file that your virtual machine does not really use. You can then safely launch the virtual machine from the summary screen.