使用ExtAudioFileWrite在文件末尾寫入

Question

我試圖打開一個文件並使用ExtAudioFileWrite將數據追加到它。現在，創建/初始寫入（創建時）/轉換工作很好，但不幸的是，我似乎無法打開文件以供後來寫入。只有一個函數似乎打開文件：ExAudioFileOpenURL，但僅用於閱讀。那麼，如果我無法打開文件進行寫入，我該如何在文件末尾編寫代碼？

Answer 1

我可能是錯的，或不完全理解你的問題。但是，一旦使用ExtAudioFileWrite開始寫入文件，您可以通過再次調用ExtAudioFileWrite來繼續寫入文件。我要冒險進入沒有編譯器的編碼，希望你會得到的想法

例子：

....variables declaration and your logic..... 

//1.Create File to write output 
ExtAudioFileRef outputFile; 

//+++++++ LOOP to append as many files as you want +++++++// 

//2.Create file reference to files you want to merge 
ExtAudioFileRef audioFileObject = 0; 

//3.open the first file 
ExtAudioFileOpenURL (firstFileURL, &audioFileObject); 

//4.get file properties 
AudioStreamBasicDescription AudioFileFormat = 0; 
UInt64 numberOfPacketsToReadInCurrentFile = 0; 
ExtAudioFileGetProperty(audioFileObject, 
         kExtAudioFileProperty_FileLengthFrames, 
         sizeof(numberOfPacketsToReadInCurrentFile), 
         &numberOfPacketsToReadInCurrentFile 
         ); 

ExtAudioFileGetProperty(audioFileObject, 
         kExtAudioFileProperty_FileDataFormat, 
         sizeof(AudioFileFormat), 
         &AudioFileFormat 
         ); 
//5.Set destination ASBD 
ExtAudioFileSetProperty(audioFileObject, 
         kExtAudioFileProperty_ClientDataFormat, 
         sizeof (importFormat), 
         &importFormat 
         ); 

//6.Set/Create/Allocate Some Buffers 
//use AudioFileFormat to setup your buffers accordingly 

AudioBufferList theBufferList = 0 // bufferList setup (I dont remember that) 

//7.Read the file into the buffer 
ExtAudioFileRead(audioFileObject,&numberOfPacketsToReadInCurrentFile,theBufferList); 

//8.Write the buffer to a File  
ExtAudioFileWrite(outputFile, numberOfPacketsToReadInCurrentFile, theBufferList); 
free(theBufferList); 

//if you want to append more files go to point 2 with the next file URL 

//+++++++CLOSE LOOP+++++++++// 

//once you are done.. just dispose the file and clean up everything left 
ExtAudioFileDispose(outputFile); 

這將無法編譯，我猜。但希望能幫助你明白這個想法。