ios - OSStatus 错误 -50(无效参数)AudioQueueNewInput 在 iOS 上录制音频
<p><p>多年来，我一直在互联网上搜寻这个错误的原因，但我被困住了。我一直在关注使用音频服务录制音频的 Apple 开发人员文档，无论我做什么，我都会不断收到此错误。</p>
<p>我可以使用 <code>AVAudioRecorder</code> 将音频很好地录制成任何格式，但我的最终目标是从输入数据中获取一个标准化的 float 组，以便对其应用 FFT(对于菜鸟的措辞感到抱歉我对音频编程很陌生)。</p>
<p>这是我的代码:</p>
<pre><code>- (void)beginRecording
{
// Initialise session
[ setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
[ setActive:YES error:nil];
state.dataFormat.mFormatID = kAudioFormatLinearPCM;
state.dataFormat.mSampleRate = 8000.0f;
state.dataFormat.mChannelsPerFrame = 1;
state.dataFormat.mBitsPerChannel = 16;
state.dataFormat.mBytesPerPacket = state.dataFormat.mChannelsPerFrame * sizeof(SInt16);
state.dataFormat.mFramesPerPacket = 1;
//AudioFileTypeID fileID = kAudioFileAIFFType;
state.dataFormat.mFormatFlags = kLinearPCMFormatFlagIsBigEndian | kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked;
OSStatus err = AudioQueueNewInput(&state.dataFormat, handleInputBuffer, &state, CFRunLoopGetMain(), kCFRunLoopCommonModes, 0, &state.queue);
printf("%i", err); // this is always -50 i.e. invalid parameters error
deriveBufferSize(state.queue, state.dataFormat, 0.5, &state.bufferByteState);
for (int i = 0; i < kNumberOfBuffers; i++) {
AudioQueueAllocateBuffer(state.queue, state.bufferByteState, &state.buffers);
AudioQueueEnqueueBuffer(state.queue, state.buffers, 0, NULL);
}
state.currentPacket = 0;
state.isRunning = YES;
AudioQueueStart(state.queue, NULL);
}
- (void)endRecording
{
AudioQueueStop(state.queue, YES);
state.isRunning = NO;
AudioQueueDispose(state.queue, YES);
// Close the audio file here...
}
#pragma mark - CoreAudio
// Core Audio Callback Function
static void handleInputBuffer(void *agData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer, const AudioTimeStamp *inStartTime, UInt32 inNumPackets, const AudioStreamPacketDescription *inPacketDesc) {
AQRecorderState *state = (AQRecorderState *)agData;
if (inNumPackets == 0 && state->dataFormat.mBytesPerPacket != 0) {
inNumPackets = inBuffer->mAudioDataByteSize / state->dataFormat.mBytesPerPacket;
}
printf("Called");
/*
if (AudioFileWritePackets(state->audioFile, false, inBuffer->mAudioDataByteSize, inPacketDesc, state->currentPacket, &inNumPackets, inBuffer->mAudioData) == noErr) {
state->currentPacket += inNumPackets;
}
*/
if (state->isRunning) {
AudioQueueEnqueueBuffer(state->queue, inBuffer, 0, NULL);
}
}
void deriveBufferSize(AudioQueueRef audioQueue, AudioStreamBasicDescription ABSDescription, Float64 secs, UInt32 *outBufferSize) {
static const int maxBufferSize = 0x50000;
int maxPacketSize = ABSDescription.mBytesPerPacket;
if (maxPacketSize == 0) {
UInt32 maxVBRPacketSize = sizeof(maxPacketSize);
AudioQueueGetProperty(audioQueue, kAudioConverterPropertyMaximumOutputPacketSize, &maxPacketSize, &maxVBRPacketSize);
}
Float64 numBytesForTime = ABSDescription.mSampleRate * maxPacketSize * secs;
UInt32 x = (numBytesForTime < maxBufferSize ? numBytesForTime : maxBufferSize);
*outBufferSize = x;
}
</code></pre>
<p>如果有人知道这里发生了什么，我将不胜感激。 <a href="https://developer.apple.com/library/ios/documentation/Security/Reference/keychainservices/index.html#//apple_ref/c/econst/errSecParam" rel="noreferrer noopener nofollow">Here is the apple docs for the error</a> </p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>你得到一个 -50 (<code>kAudio_ParamError</code>) 因为你还没有初始化 <code>AudioStreamBasicDescription</code> 的 <code>mBytesPerFrame</code> 字段:</p>
<pre><code>asbd.mBytesPerFrame = asbd.mFramesPerPacket*asbd.mBytesPerPacket;
</code></pre>
<p>其中 <code>asbd</code> 是 <code>state.dataFormat</code> 的缩写。在您的情况下 <code>mBytesPerFrame = 2</code>.</p>
<p>我也不会指定 <code>kLinearPCMFormatFlagIsBigEndian</code>，让记录器返回您的原生字节顺序样本。</p></p>
<p style="font-size: 20px;">关于ios - OSStatus 错误 -50(无效参数)AudioQueueNewInput 在 iOS 上录制音频，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/30413180/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/30413180/
</a>
</p>
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