AudioSteamBasicDescription kAudioFormatFlagIsNonInterleaved 与 Interleaved 的区别与构造

最新推荐文章于 2021-10-15 10:09:21 发布

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本文探讨了音频格式中的kAudioFormatFlagIsNonInterleaved标志，该标志指示音频是否为非交织。非交织音频每个通道的数据分别存储，而交织音频则将所有通道数据混合在一起存储。代码示例展示了如何根据音频格式创建相应的AudioBufferList结构，用于处理非交织和交织音频的内存分配和初始化。

if (outputFormat.mFormatFlags & kAudioFormatFlagIsNonInterleaved) {
        // The audio is non-interleaved
        printf("Not interleaved!\n");
        self.isInterleaved = NO;

        // allocate an AudioBufferList plus enough space for array of AudioBuffers
       UInt32 propsize = offsetof(AudioBufferList, mBuffers[0]) + (sizeof(AudioBuffer) * outputFormat.mChannelsPerFrame);

       //malloc buffer lists
       self.inputBuffer = (AudioBufferList *)malloc(propsize);
       self.inputBuffer->mNumberBuffers = outputFormat.mChannelsPerFrame;

       //pre-malloc buffers for AudioBufferLists
       for(UInt32 i =0; i< self.inputBuffer->mNumberBuffers ; i++) {
           self.inputBuffer->mBuffers[i].mNumberChannels = 1;
           self.inputBuffer->mBuffers[i].mDataByteSize = bufferSizeBytes;
           self.inputBuffer->mBuffers[i].mData = malloc(bufferSizeBytes);
            memset(self.inputBuffer->mBuffers[i].mData, 0, bufferSizeBytes);
       }
   } else {
       printf ("Format is interleaved\n");
        self.isInterleaved = YES;

       // allocate an AudioBufferList plus enough space for array of AudioBuffers
       UInt32 propsize = offsetof(AudioBufferList, mBuffers[0]) + (sizeof(AudioBuffer) * 1);

       //malloc buffer lists
       self.inputBuffer = (AudioBufferList *)malloc(propsize);
       self.inputBuffer->mNumberBuffers = 1;

       //pre-malloc buffers for AudioBufferLists
       self.inputBuffer->mBuffers[0].mNumberChannels = outputFormat.mChannelsPerFrame;
       self.inputBuffer->mBuffers[0].mDataByteSize = bufferSizeBytes;
       self.inputBuffer->mBuffers[0].mData = malloc(bufferSizeBytes);
        memset(self.inputBuffer->mBuffers[0].mData, 0, bufferSizeBytes);
   }