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  1. #1
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    Angry QtMultimedia on Symbian, again...

    Now that we got a backend for QtMultimedia with Qt 4.6.3 I am wondering whether I am the only one who as serious problems using it. I wasted the last two days trying to port my little sample application: http://wiki.forum.nokia.com/index.php/QtKeyboard to the multimedia api as promised.

    Yesterday I got something working on the desktop but when playing around today with the device I found out that "pull"-mode during audio output is not working on symbian. This is not a so big surprise for me because I found a similar behaviour on Mac but in the other direction (audioinput).

    Of course both behaviours have been reported:
    http://bugreports.qt.nokia.com/browse/QTBUG-12742
    http://bugreports.qt.nokia.com/browse/QTBUG-5741

    Both behaviours are not documented...of course

    ATM I am pissed of and have to release some steam because I cannot understand how features that where announced in 4.6.0 and only delivered in 4.6.3 where not tested at all before the release given the extra time. I wonder how it long takes till we get a usable development environment that does what the documentation says. I mean, I would like to invest more time in developing for nokia devices but currently it is not investing but wasting. I tried all of them: 4.6.0, 4.6.1, 4.6.2 and with 4.6.3 I thought I could finaly use multimedia. But no, they fooled me again. Notice that there was no official statement that the multimedia backend was missing in 4.6.0-4.6.2 at all.

    So I raise the question: Who else uses this API? Maybe there is ways to work around all that problems? Maybe you use your own wrapper around the native symbian API as I did with the original keyboard application?
    Last edited by axeljaeger; 2010-08-08 at 21:25.

  2. #2
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    Re: QtMultimedia on Symbian, again...

    I'm with you on this one, buddy. My application relies heavily on media playing, but thank god for me, I only need basic playing of mp3s and videos.

    I got everything working, my only problem is that the PC simulator throws that the media service isn't available, I checked and yep, there're no multimedia .dlls for the Symbian emulator, worst of all, I tried downloading QtMobility 1.0.2 and it's not even remotely possible to compile given the amount of errors it throws.
    And given that it takes around 5 minutes for a small-sized project to compile for the device so we can test the media system on it, we wasted 2 days trying to make the system work when it could've just taken a couple of hours.

    All in all, I still think Qt 4.6 with its Symbian support is a HUGE step from the ridiculously complex Symbian C++. And I truly feel that our current application would've taken 3 or 4 times more if had been done on pure Symbian.

    So my best bet is that 4.7 and its successive patches will finally get rid of these basic issues (like not being able to use custom fonts!) and take the platform much closer to what the iPhone and Android are.

    Best!
    Matias

  3. #3
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    Re: QtMultimedia on Symbian, again...

    Does your application respond in "nearly realtime"? My current problem is that I can play audio but with a delay of about 1 second. I am currently investigating whether this is related to this bug: http://bugreports.qt.nokia.com/browse/QTBUG-9402
    But I think the 4096 buffer cant be the reason for a 1 second delay.

    For you problem, you can try to compile your application against a desktop Qt. Audio should be working then. You will have to install the Qt SDK by Nokia next to the Nokia Qt SDK to get that working. But remember that due to a bug, the remote compiler from the Nokia SDK does not work when there is a desktop Qt installed in parallel.
    Last edited by axeljaeger; 2010-08-09 at 13:28.

  4. #4
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    Re: QtMultimedia on Symbian, again...

    Yes it does, but I've accepted this due to the fact that in order to play mp3s, a stream buffer initialization needs to take place which usually takes a second. This is at least true on the iPhone platform. In order to achieve true real-time playback (ie. for games), we usually stick to .wavs.

    Perhaps there is a way to pre-buffer the MP3s you're going to use or something? I really have no idea.

    About the compiling against Desktop Qt, that would've come handy before! But I don't want to risk getting into conflicting issues, much more if there're known bugs regarding that, I'm worried there may be much worse not-known bugs out there.

  5. #5
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    Re: QtMultimedia on Symbian, again...

    Hi,
    here my plan is to generate the audio data during playback. If my user presses a certain key, I want a sine generator to generate a tone and stop when the user lifts the finger again. I get about 1 sec delay. This basically works with a native symbian implementation and I have problems adopting it to QtMultimedia. I will have to have a deeper look into my code to make sure I dont make any mistake. But given my latest experiences on symbian I fear that I find more undocumented differences between desktop and mobile Qt.

    For people who did native symbian coding before, Qt must be a gift from the goods. But for a desktop developer coming from Qt desktop, the situation is painfull. We are used to have a toolkit that works as documented. It feels uncomfortable to start debugging the own toolkit.

    Regarding desktop Qt: I think installing the the Desktop SDK is not a great risk. I fear more bugs in the mobile stuff than in the desktop SDK. On the desktop, they are in business for a few more years and my feeling is that they are just brilliant in messing up the mobile stuff.

    Edit: Can someone else besides me reproduce the first bug mentioned in my first post? I still can even nokia cannot.
    Last edited by axeljaeger; 2010-08-09 at 15:22.

  6. #6
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    Re: QtMultimedia on Symbian, again...

    Ou, what a nice post. At the moment I am also in the mood of release some steam after I played around to get the mobile extensions working for a day, and the last patch from the bugreports page made my Qt SDK stop working. Happy times!:-( I think, much stuff of Qt is tooo poorly documented. I switched over from Android Development and was thinking that Andrdoid is very bad documented. But now I know better...
    For your problems. I also played around with QMultimedia and weren't able to make it work to play. My task is to make a mp3 radio stream from the internet play and I didn't managed to get that working. I switched to phonon and that works pretty good on newer devices (N97 and N900), but not on E72. Anyway, if you are not sticked to QMultimedia I would suggest to try Phonon. If you need sample code, ping me.

    Cheers, Lukas

  7. #7
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    Re: QtMultimedia on Symbian, again...

    Unfortunately I think I have to stick with QtMultimedia because I want create my audio data in realtime and thus need raw access to the audiostream. Can you try out on your device whether both push and pull mode work in the example "audiooutput" that ships with Qt? At least I want to hunt down that one bug.

    Edit: Actually, there is an official statement that there was no multimedia backend on symbian:
    http://doc.qt.nokia.com/latest/platf...s-symbian.html

    However, it was not updated to reflect the current state that there is now such a backend.
    Last edited by axeljaeger; 2010-08-10 at 22:01.

  8. #8
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    Thumbs up installing Qtmobility application into N8

    hi,

    installing qtmobility application into hardware(symbian device)
    I am able to play music as as well as audio using the Qtmultimedia mobility api.I am sharing what i have done it to make it work.All u have to do is

    step 1: get nokiaqtsdk1_0_2

    step2: get latest Qt_installer.sis from your nokiaqt sdk C:\NokiaQtSDK_1.0.2\Symbian\sis

    step 3: get latest Qtmobility of version 1.1.0 from this following link
    http://qt.nokia.com/products/qt-addons/mobility

    step4 : Down load qt-mobility-symbian-opensource-1.1.0.zip from the above same link&then extract contents of epoc 32 folder into the corresponding C:\NokiaQtSDK\Symbian\SDK\epoc32 folder.

    step5: build your application after setting the target for Symbian device

    step6: once your application has been built&cretaed the sis file,install these 3 sis files(qt_installer.sisx,qt-mobility-symbian-1.1.0-symbian3.sisx and application.sisx)

    then launch u'r application!!!!tht's all....

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