Question

我试图实现一种拉伸声速的功能，而不改变它的音高和时间刻度。

我尝试使用这种方法将频道频率设置为快速减速。

然后使用FMOD_DSP_PITCHSHIFT将音高声音校正为默认值。

我使用wav格式声音文件进行测试和构建功能。

我试图整合声音文件被编码为MP3的产品资源。

PITCHSHIFT DSP不适用于MP3声道。控制台日志看起来很好，没有例外＆amp;错误。

相同的项目和设置在iOS模拟器中一切正常。

经过一些研究和实验，结果表明即使m4a在iOS上运行良好。

我想知道这是一种什么样的错误吗？或者我错过了一些配置。示例代码基于FMOD示例项目播放流。

`/*==============================================================================
Play Stream Example
Copyright (c), Firelight Technologies Pty, Ltd 2004-2015.

This example shows how to simply play a stream such as an MP3 or WAV. The stream
behaviour is achieved by specifying FMOD_CREATESTREAM in the call to 
System::createSound. This makes FMOD decode the file in realtime as it plays,
instead of loading it all at once which uses far less memory in exchange for a
small runtime CPU hit.
==============================================================================*/
#include "fmod.hpp"
#include "common.h"

int FMOD_Main()
{
    FMOD::System     *system;
    FMOD::Sound      *sound, *sound_to_play;
    FMOD::Channel    *channel = 0;
    FMOD_RESULT       result;
    FMOD::DSP        * pitch_shift;
    unsigned int      version;
    void             *extradriverdata = 0;
    int               numsubsounds;

    Common_Init(&extradriverdata);

    /*
        Create a System object and initialize.
    */
    result = FMOD::System_Create(&system);
    ERRCHECK(result);

    result = system->getVersion(&version);
    ERRCHECK(result);

    if (version < FMOD_VERSION)
    {
        Common_Fatal("FMOD lib version %08x doesn't match header version %08x", version, FMOD_VERSION);
    }

    result = system->init(32, FMOD_INIT_NORMAL, extradriverdata);
    ERRCHECK(result);

    result = system->createDSPByType(FMOD_DSP_TYPE_PITCHSHIFT, &pitch_shift);
    ERRCHECK(result);


    /*
        This example uses an FSB file, which is a preferred pack format for fmod containing multiple sounds.
        This could just as easily be exchanged with a wav/mp3/ogg file for example, but in this case you wouldnt need to call getSubSound.
        Because getNumSubSounds is called here the example would work with both types of sound file (packed vs single).
    */
    result = system->createSound(Common_MediaPath("aaa.m4a"), FMOD_LOOP_NORMAL | FMOD_2D, 0, &sound);
    ERRCHECK(result);

    result = sound->getNumSubSounds(&numsubsounds);
    ERRCHECK(result);

    if (numsubsounds)
    {
        sound->getSubSound(0, &sound_to_play);
        ERRCHECK(result);
    }
    else
    {
        sound_to_play = sound;
    }

    /*
        Play the sound.
    */
    result = system->playSound(sound_to_play, 0, false, &channel);
    ERRCHECK(result);
    result = channel->addDSP(0, pitch_shift);
    ERRCHECK(result);
            float        pitch = 1.f;
    result = pitch_shift->setParameterFloat(FMOD_DSP_PITCHSHIFT_PITCH, pitch);
    ERRCHECK(result);
    pitch_shift->setActive(true);
    ERRCHECK(result);
    float defaultFrequency;
    result = channel->getFrequency(&defaultFrequency);
    ERRCHECK(result);
    /*
        Main loop.
    */
    do
    {
        Common_Update();

        if (Common_BtnPress(BTN_ACTION1))
        {
            bool paused;
            result = channel->getPaused(&paused);
            ERRCHECK(result);
            result = channel->setPaused(!paused);
            ERRCHECK(result);
        }
        if (Common_BtnPress(BTN_DOWN)) {
            char valuestr;
            int valuestrlen;
            pitch_shift->getParameterFloat(FMOD_DSP_PITCHSHIFT_PITCH, &pitch, &valuestr, valuestrlen);
            pitch+=0.1f;
            pitch = pitch>2.0f?2.0f:pitch;
            pitch_shift->setParameterFloat(FMOD_DSP_PITCHSHIFT_PITCH, pitch);
            channel->setFrequency(defaultFrequency/pitch);

        }
        if (Common_BtnPress(BTN_UP)) {
            char valuestr;
            int valuestrlen;
            pitch_shift->getParameterFloat(FMOD_DSP_PITCHSHIFT_PITCH, &pitch, &valuestr, valuestrlen);
            pitch-=0.1f;
            pitch = pitch<0.5f?0.5f:pitch;
            pitch_shift->setParameterFloat(FMOD_DSP_PITCHSHIFT_PITCH, pitch);
            channel->setFrequency(defaultFrequency/pitch);
        }

        result = system->update();
        ERRCHECK(result);

        {
            unsigned int ms = 0;
            unsigned int lenms = 0;
            bool         playing = false;
            bool         paused = false;

            if (channel)
            {
                result = channel->isPlaying(&playing);
                if ((result != FMOD_OK) && (result != FMOD_ERR_INVALID_HANDLE))
                {
                    ERRCHECK(result);
                }

                result = channel->getPaused(&paused);
                if ((result != FMOD_OK) && (result != FMOD_ERR_INVALID_HANDLE))
                {
                    ERRCHECK(result);
                }

                result = channel->getPosition(&ms, FMOD_TIMEUNIT_MS);
                if ((result != FMOD_OK) && (result != FMOD_ERR_INVALID_HANDLE))
                {
                    ERRCHECK(result);
                }

                result = sound_to_play->getLength(&lenms, FMOD_TIMEUNIT_MS);
                if ((result != FMOD_OK) && (result != FMOD_ERR_INVALID_HANDLE))
                {
                    ERRCHECK(result);
                }
            }

            Common_Draw("==================================================");
            Common_Draw("Play Stream Example.");
            Common_Draw("Copyright (c) Firelight Technologies 2004-2015.");
            Common_Draw("==================================================");
            Common_Draw("");
            Common_Draw("Press %s to toggle pause", Common_BtnStr(BTN_ACTION1));
            Common_Draw("Press %s to quit", Common_BtnStr(BTN_QUIT));
            Common_Draw("");
            Common_Draw("Time %02d:%02d:%02d/%02d:%02d:%02d : %s", ms / 1000 / 60, ms / 1000 % 60, ms / 10 % 100, lenms / 1000 / 60, lenms / 1000 % 60, lenms / 10 % 100, paused ? "Paused " : playing ? "Playing" : "Stopped");
            Common_Draw("Pitch %02f",pitch);
        }

        Common_Sleep(50);
    } while (!Common_BtnPress(BTN_QUIT));

    /*
        Shut down
    */
    result = sound->release();  /* Release the parent, not the sound that was retrieved with getSubSound. */
    ERRCHECK(result);
    result = system->close();
    ERRCHECK(result);
    result = system->release();
    ERRCHECK(result);

    Common_Close();

    return 0;
}

`

Answer 1

经过一些实验，我可以通过切换声音文件格式到达iOS设备上的m4a。 MP3仍无法正常工作。

FMOD_DSP_PITCHSHIFT不适用于iOS

1 个答案: