我想要在播放WAV檔的同時，利用TrackBar直接調整播放的速度.. 我看過版上的類似問題，是利用取樣率來修改.. <textarea class="cpp" rows="10" cols="60" name="code">TMemoryStream *wav_stream=new TMemoryStream(); wav_stream->LoadFromFile(wavname); long newSamplingRate=52000; wav_stream->Position=24; wav_stream->Write(&newSamplingRate,4);</textarea>
可是在寫記憶體放音的時候，要怎樣即時去修改標頭檔的取樣率呢？ 以下是我參考書上的記憶體放音的程式.. 請各位高手幫忙，謝謝..
<textarea class="cpp" rows="10" cols="60" name="code"> void __fastcall Tf14_5_1::btnPlayClick(TObject *Sender) { char szOpenError[] = "Open device Error!"; if(pVoiceBuffer == NULL) { MessageDlg("No data for playing!",mtWarning,TMsgDlgButtons()<Enabled = true; dwDataSize = lFileSize; pFormat.wFormatTag = WAVE_FORMAT_PCM; pFormat.nChannels = sChannels; pFormat.nSamplesPerSec = lSamplingRate; if(sBitsPerSample == 8) { pFormat.nAvgBytesPerSec = lSamplingRate * sChannels * (sBitsPerSample / 8); pFormat.nBlockAlign = sChannels * (sBitsPerSample / 8); pFormat.wBitsPerSample = 8; } else // 16 bits { pFormat.nAvgBytesPerSec = lSamplingRate * sChannels * (sBitsPerSample / 8); pFormat.nBlockAlign = sChannels * (sBitsPerSample / 8);; pFormat.wBitsPerSample = 16; } pFormat.cbSize = 0; if( !(waveOutOpen((LPHWAVEOUT)&hWaveOut, WAVE_MAPPER,(LPWAVEFORMATEX)&pFormat ,(DWORD)f14_5_1->Handle, 0, 0) == MMSYSERR_NOERROR) ) { MessageDlg(szOpenError,mtInformation,TMsgDlgButtons()<Enabled = false; // Allocate and lock memory for the header. hWaveHdr = GlobalAlloc(GMEM_MOVEABLE | GMEM_SHARE, (DWORD)sizeof(WAVEHDR)); if(hWaveHdr == NULL) { MessageDlg("Not enough memory for header.",mtInformation,TMsgDlgButtons()<lpData = (char *)pVoiceBuffer; lpWaveHdr->dwBufferLength = lFileSize; lpWaveHdr->dwFlags = 0L; //WHDR_BEGINLOOP | WHDR_ENDLOOP; lpWaveHdr->dwLoops = 0L; // // if(waveOutPrepareHeader(hWaveOut, lpWaveHdr, sizeof(WAVEHDR)) != MMSYSERR_NOERROR) { MessageDlg("WaveOutPrepareHeader Error 1!",mtInformation,TMsgDlgButtons()<ProcessMessages(); } if(waveOutReset(hWaveOut) != MMSYSERR_NOERROR) { MessageDlg("WaveOutReset Error!",mtInformation,TMsgDlgButtons()<Enabled = true; btnStop->Enabled = false; } } </textarea>