[FFmpeg-devel] Parallelizing MPEG encoding with MPI

[Roman Shaposhnik]

On Dec 6, 2008, at 8:22 PM, M?ns Rullg?rd wrote:
> Roman Shaposhnik <rvs at sun.com> writes:
>
>> On Dec 6, 2008, at 8:08 PM, M?ns Rullg?rd wrote:
>>> "Jason Garrett-Glaser" <darkshikari at gmail.com> writes:
>>>
>>>> On Sat, Dec 6, 2008 at 12:20 PM, Andreas Simbuerger <simi at osaft.eu>
>>>> wrote:
>>>>> Greetings everybody!
>>>>>
>>>>> I'm currently working on a programming exercise for my diploma at
>>>>> the
>>>>> University of Passau. We try to enhance MPEG encoding by  
>>>>> introducing
>>>>> parallelism on GOP encoding with the MPI libraries.
>>>>
>>>> Isn't MPI rather unnecessary for video encoding parallelism?  It is
>>>> rather easy to develop a model (see
>>>> http://akuvian.org/src/x264/sliceless_threads.txt) which does not
>>>> require communication between threads except to signal the maximum
>>>> motion vector search range, which can be done using an atomic write
>>>> to
>>>> a struct variable.
>>>
>>> MPI works on networks of machines with no shared memory.
>>
>> Not quite true. MPI implementations are capable of utilizing
>> shared memory for message passing if they notice that entities
>> are running on the same machine. That's one way of utilizing
>> those crazy multicore CPUs *and* clusters at the same time -- just
>> write MPI and let the runtime figure out the most efficient way
>> of passing messages.
>
> What I said is true, but not the entire truth.

True ;-)

Thanks,
Roman.