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  1. #1
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    Question Creating an MPEG-4 encoder

    Hi

    We curently develop a prototype for an MPEG-4 encoder, multithreaded.
    I'm looking for an embedded platform, to test it.

    Can I run it on series60 phones ?
    Is the processor powerfull enough to run this kind of software ?
    Do we have acces to the video stream from the built in camera ?

    thanks a lot

    fx

  2. #2
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    Re: Creating an MPEG-4 encoder

    > We curently develop a prototype for an MPEG-4 encoder, multithreaded.
    > I'm looking for an embedded platform, to test it.
    ARM with MMU is not very good platform for multithreading(*), I hope your program can run in a single thread as well.
    (* or there're no lightweight threads in Symbian, but anyway multithreading should be avoided)

    > Can I run it on series60 phones ?
    Why not, after porting. There's no FPU as well - you don't use any floating-point arithmetics, do you?

    > Is the processor powerfull enough to run this kind of software ?
    I don't really think so, but it depends on quality you can accept.

    > Do we have acces to the video stream from the built in camera ?
    There's also some built-in video recording application in my 6630, it records in video/3gpp format with a resolution of 176x144 and a bitrate of 64kbps, but probably it's hardware assisted I don't know.
    Also people in forums complain APIs for real-time video access are closed, it's only possible to record and play finite clips with ones that available.

  3. #3
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    Re: Creating an MPEG-4 encoder

    yes u can in ur application in series 60 arm architecture and has floating point but can't be used effectively.

  4. #4
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    Re: Creating an MPEG-4 encoder

    Hi all
    thanks for your answer

    my goal is to adapt a software MPEG4 encoder, on an embedded platform.
    I want to use multi-threading, which is one key of our software. I read that since v7, symbian OS is a multi-tasking Os, do you know the mechanism availables (thread, process, what kind of synchro ???) ???

    Talking about the video stream, do you think I can acces to the raw input stream, directly from the camera ?
    I think there must be hardware coprocessing for the encoder provided with the phones ...

    thanks a lot
    fx

  5. #5
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    Re: Creating an MPEG-4 encoder

    > I want to use multi-threading, which is one key of our software. I read that since v7, symbian OS is a multi-tasking Os, do you know the mechanism availables (thread, process, what kind of synchro ???) ???
    + What good is multithreading for you? Cellphones don't have multiple processors anyway, and I/O is already asynchronous in a different way. Symbian OS is multi-tasking OS, but switching between independent threads too often is slow and not recommended. Instead there's something called active objects, essencially call-backs but object-oriented. These are used for I/O, user-interface and like to be asynchronous. It's different from threads in that another active object belonging to the same process will never be dispatched until current object will finish processing. See http://www.symbian.com/developer/tec...cts/active.htm for more information.

    > Talking about the video stream, do you think I can acces to the raw input stream, directly from the camera ?
    + You can surely capture a series of low-resolution still images as a workaround.

    > I think there must be hardware coprocessing for the encoder provided with the phones ...
    + I think you should check hardware specs for specific devices, they are all different. However working directly with hardware is yet another story, I'm not sure you can do it without direct manufacturer's help or reverse-engineering something.

  6. #6
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    Re: Creating an MPEG-4 encoder

    Ok thanks

    multithreading (in its POSIX definition), is what I need, with Lock/Unlock mechanisms, so symbian Os is not what I need...

    I take a look at windows mobile, but :

    - I do not like windows programming
    - I do not have acces to the camera API (only in future 5.0 revision)

    Have you any idea (embedded platform with camera, thread-ready OS) ????

    thanks a lot
    fx

  7. #7
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    Re: Creating an MPEG-4 encoder

    Quote Originally Posted by fxdfxd
    multithreading (in its POSIX definition), is what I need, with Lock/Unlock mechanisms, so symbian Os is not what I need...
    Yes, posix thread functions are explicitly unsupported by Symbian. Can you explain you task more clearly, how came you cannot cut it with one thread and without need of Lock/Unlock mechanism? Asynchronious thread switching will only add problems unless your goal is exercise in parallel programming.

    Quote Originally Posted by fxdfxd
    Have you any idea (embedded platform with camera, thread-ready OS) ????
    + I can only say that it is not ARM with MMU, and probably not cellphones at all - thread switching is unnecessary waste of resources. I've heard there's an implementation of linux for MMU-less ARM (search for link on slashdot.org), but not sure if it supports posix threads or cameras. Check embedded PowerPC. Most likely it will be Linux anyways, and bare platform, not end-user device.

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