[Openal] AL_*_OFFSET resolution

[Casey Borders]

Are you streaming the file or loading the whole thing in at once?  It's hard
to pull a small cohesive example out of my code, but you can have a look at
it on Sourceforge at http://sourceforge.net/projects/ogreal You'll want to
look in the OggSound class.  Here's the pertinent bit:

    void OggSound::setSecondOffset(Ogre::Real seconds)
    {
        if(!mStream)
        {
            alSourcef(mSource, AL_SEC_OFFSET, seconds);
            CheckError(alGetError(), "Failed to set offset");
        }
        else
        {
            bool wasPlaying = isPlaying();

            pause();
            ov_time_seek(&mOggStream, seconds);

            if(wasPlaying) play();
        }
    }

Here are my helper functions:

    bool Sound::isPlaying() const
    {
        if(mSource == AL_NONE)
        {
            return false;
        }

        State state;
        alGetSourcei(mSource, AL_SOURCE_STATE, &state);
        CheckError(alGetError(), "Failed to get State");

        return (state == AL_PLAYING);
    }

    bool Sound::pause()
    {
        if(!isPlaying()) return true;

        if(mSource != AL_NONE)
        {
            alSourcePause(mSource);
            CheckError(alGetError(), "Failed to pause sound");
        }

        return false;
    }

    bool Sound::play()
    {
        if(isPlaying()) return true;

        if(mStartTime == 0)
        {
            time(&mStartTime);
        }
        else if(!isPaused())
        {
            time_t currentTime;
            time(&currentTime);

            setSecondOffset(currentTime - mStartTime);
        }

        if(mSource != AL_NONE || (mSource =
SoundManager::getSingleton()._requestSource(this)) != AL_NONE)
        {
            if(!mBuffersLoaded)
            {
                mBuffersLoaded = loadBuffers();
            }

            if(!mBuffersQueued)
            {
                // Unqueue any buffers that may be left over
                unqueueBuffers();
                queueBuffers();
            }

            initSource();

            alSourcePlay(mSource);
            CheckError(alGetError(), "Failed to play sound");
        }

        return false;
    }

On Dec 7, 2007 12:15 PM, Ben Swanson <dujiaozhu at gmail.com> wrote:

> I am attempting to sync an animation to a sound file using the
> AL_SEC_OFFSET property.  The problem I am having is that the resolution of
> the command seems to be 4096 samples, which leads to a choppy animation.  Is
> there a way  to change this (the sound file is in ogg vorbis format)?
>
> Ben
>
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> Openal at opensource.creative.com
> http://opensource.creative.com/mailman/listinfo/openal
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>
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