Ho cercato di scrivere un video + audio utilizzando AVAssetWriter e AVAssetWriterInputs.Questo codice per scrivere video + audio tramite AVAssetWriter e AVAssetWriterInputs non funziona. Perché?
Ho letto più post in questo forum di persone che dicono di essere in grado di farlo, ma non funziona per me. Se scrivo solo video, il codice sta facendo il suo lavoro molto bene. Quando aggiungo l'audio, il file di output è danneggiato e non può essere riprodotto.
Ecco parte del mio codice:
Impostazione AVCaptureVideoDataOutput e AVCaptureAudioDataOutput:
NSError *error = nil;
// Setup the video input
AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeVideo];
// Create a device input with the device and add it to the session.
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
// Setup the video output
_videoOutput = [[AVCaptureVideoDataOutput alloc] init];
_videoOutput.alwaysDiscardsLateVideoFrames = NO;
_videoOutput.videoSettings =
[NSDictionary dictionaryWithObject:
[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
// Setup the audio input
AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeAudio];
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error ];
// Setup the audio output
_audioOutput = [[AVCaptureAudioDataOutput alloc] init];
// Create the session
_capSession = [[AVCaptureSession alloc] init];
[_capSession addInput:videoInput];
[_capSession addInput:audioInput];
[_capSession addOutput:_videoOutput];
[_capSession addOutput:_audioOutput];
_capSession.sessionPreset = AVCaptureSessionPresetLow;
// Setup the queue
dispatch_queue_t queue = dispatch_queue_create("MyQueue", NULL);
[_videoOutput setSampleBufferDelegate:self queue:queue];
[_audioOutput setSampleBufferDelegate:self queue:queue];
dispatch_release(queue);
Impostazione AVAssetWriter e associando entrambe AVAssetWriterInputs audio e video ad esso:
- (BOOL)setupWriter {
NSError *error = nil;
_videoWriter = [[AVAssetWriter alloc] initWithURL:videoURL
fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(_videoWriter);
// Add video input
NSDictionary *videoCompressionProps = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithDouble:128.0*1024.0], AVVideoAverageBitRateKey,
nil ];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:192], AVVideoWidthKey,
[NSNumber numberWithInt:144], AVVideoHeightKey,
videoCompressionProps, AVVideoCompressionPropertiesKey,
nil];
_videoWriterInput = [[AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings] retain];
NSParameterAssert(_videoWriterInput);
_videoWriterInput.expectsMediaDataInRealTime = YES;
// Add the audio input
AudioChannelLayout acl;
bzero(&acl, sizeof(acl));
acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
NSDictionary* audioOutputSettings = nil;
// Both type of audio inputs causes output video file to be corrupted.
if (NO) {
// should work from iphone 3GS on and from ipod 3rd generation
audioOutputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatMPEG4AAC ], AVFormatIDKey,
[ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
[ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
[ NSNumber numberWithInt: 64000 ], AVEncoderBitRateKey,
[ NSData dataWithBytes: &acl length: sizeof(acl) ], AVChannelLayoutKey,
nil];
} else {
// should work on any device requires more space
audioOutputSettings = [ NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatAppleLossless ], AVFormatIDKey,
[ NSNumber numberWithInt: 16 ], AVEncoderBitDepthHintKey,
[ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
[ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
[ NSData dataWithBytes: &acl length: sizeof(acl) ], AVChannelLayoutKey,
nil ];
}
_audioWriterInput = [[AVAssetWriterInput
assetWriterInputWithMediaType: AVMediaTypeAudio
outputSettings: audioOutputSettings ] retain];
_audioWriterInput.expectsMediaDataInRealTime = YES;
// add input
[_videoWriter addInput:_videoWriterInput];
[_videoWriter addInput:_audioWriterInput];
return YES;
}
qui sono funzioni per avviare/interrompere la registrazione video
- (void)startVideoRecording
{
if (!_isRecording) {
NSLog(@"start video recording...");
if (![self setupWriter]) {
return;
}
_isRecording = YES;
}
}
- (void)stopVideoRecording
{
if (_isRecording) {
_isRecording = NO;
[_videoWriterInput markAsFinished];
[_videoWriter endSessionAtSourceTime:lastSampleTime];
[_videoWriter finishWriting];
NSLog(@"video recording stopped");
}
}
E infine il codice CaptureOutput
- (void)captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection *)connection
{
if (!CMSampleBufferDataIsReady(sampleBuffer)) {
NSLog(@"sample buffer is not ready. Skipping sample");
return;
}
if (_isRecording == YES) {
lastSampleTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
if (_videoWriter.status != AVAssetWriterStatusWriting) {
[_videoWriter startWriting];
[_videoWriter startSessionAtSourceTime:lastSampleTime];
}
if (captureOutput == _videoOutput) {
[self newVideoSample:sampleBuffer];
}
/*
// If I add audio to the video, then the output file gets corrupted and it cannot be reproduced
} else {
[self newAudioSample:sampleBuffer];
}
*/
}
}
- (void)newVideoSample:(CMSampleBufferRef)sampleBuffer
{
if (_isRecording) {
if (_videoWriter.status > AVAssetWriterStatusWriting) {
NSLog(@"Warning: writer status is %d", _videoWriter.status);
if (_videoWriter.status == AVAssetWriterStatusFailed)
NSLog(@"Error: %@", _videoWriter.error);
return;
}
if (![_videoWriterInput appendSampleBuffer:sampleBuffer]) {
NSLog(@"Unable to write to video input");
}
}
}
- (void)newAudioSample:(CMSampleBufferRef)sampleBuffer
{
if (_isRecording) {
if (_videoWriter.status > AVAssetWriterStatusWriting) {
NSLog(@"Warning: writer status is %d", _videoWriter.status);
if (_videoWriter.status == AVAssetWriterStatusFailed)
NSLog(@"Error: %@", _videoWriter.error);
return;
}
if (![_audioWriterInput appendSampleBuffer:sampleBuffer]) {
NSLog(@"Unable to write to audio input");
}
}
}
Sarei molto contento se qualcuno potesse trovare che è il problema in questo codice.
Sto riscontrando problemi con le mie impostazioni audio con codice molto simile al tuo. La mia app registrerà i video ma non appena avrò detto all'AVAssetWritterInput che ho creato per l'audio ad appendSampleBuffer: mi dice 'Il buffer di input deve essere in un formato non compresso quando outputSettings non è nullo'.Hai mai incontrato questo problema? Sta guidando il mio leggermente nocciola! – Baza207
ciao kalos, l'ingresso audio nel tuo esempio proviene dal microfono o dall'applicazione stessa? – justicepenny
@kalos fratello puoi dirmi come possiamo usare videoURL. – morroko