finishWritingWithCompletionHandler can't callback

Question

Created Dec ’20

Replies 5

Boosts 0

Participants 2

i get a cvpixelbuffer from arframe,and then use AVAssetWriter to turn buffer to a video which is .mov type.
But on iphone12mini nad iphone12promax ,finishWritingWithCompletionHandler can't callback and have an error like this:

NSLocalizedDescription = "Cannot Encode";
NSLocalizedFailureReason = "The encoder required for this media is busy.";
NSLocalizedRecoverySuggestion = "Stop any other actions that encode media and try again.";
NSUnderlyingError = "Error Domain=NSOSStatusErrorDomain Code=-12915 \"The operation couldn\U2019t be completed. (OSStatus error -12915.)\"";

Answered by Onion_Shen in 652483022

just one，but i make the process in another thread

my code is just this:

Code Block 
- (BOOL)saveVideo
{
    if (!self.videoPath  self.videoPath.length == 0  !self.buffer) {
        return NO;
    }
    NSURL *url = [NSURL fileURLWithPath:self.videoPath];
    NSError *error = nil;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:url fileType:AVFileTypeQuickTimeMovie error:&error];
    if (error) {
        Log(@"%s error = %@",PRETTY_FUNCTION,error);
        return NO;
    }
    NSDictionary *videoSetting = @{
        AVVideoCodecKey:AVVideoCodecTypeH264,
        AVVideoWidthKey:@(CVPixelBufferGetWidth(self.buffer)),
        AVVideoHeightKey:@(CVPixelBufferGetHeight(self.buffer))
    };
    AVAssetWriterInput *writerInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:videoSetting];
    AVAssetWriterInputPixelBufferAdaptor *adaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] initWithAssetWriterInput:writerInput sourcePixelBufferAttributes:nil];
    if (![videoWriter canAddInput:writerInput]) {
        return NO;
    }
    [videoWriter addInput:writerInput];
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];
    CMTime presentTime = CMTimeMake(0, 600);
    while (1) {
        if ([writerInput isReadyForMoreMediaData]) {
            [adaptor appendPixelBuffer:self.buffer withPresentationTime:presentTime];
            [writerInput markAsFinished];
            block BOOL isFinish = NO;
            dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
            [videoWriter finishWritingWithCompletionHandler:^{
                isFinish = YES;
                dispatch_semaphore_signal(semaphore);
            }];
            dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, 2.0f * NSEC_PER_SEC);
            dispatch_semaphore_wait(semaphore, time);
            if (!isFinish) {
                Log(@"%s create video error",PRETTY_FUNCTION__);
            }
            break;
        }
    }
    return YES;
}

Boost

Answer 1

Media Engineer OP

Apple

Dec ’20

How many video tracks are you trying to encode at once?

0

Answer 2

Onion_Shen OP

Dec ’20

Accepted Answer

just one，but i make the process in another thread

my code is just this:

Code Block 
- (BOOL)saveVideo
{
    if (!self.videoPath  self.videoPath.length == 0  !self.buffer) {
        return NO;
    }
    NSURL *url = [NSURL fileURLWithPath:self.videoPath];
    NSError *error = nil;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:url fileType:AVFileTypeQuickTimeMovie error:&error];
    if (error) {
        Log(@"%s error = %@",PRETTY_FUNCTION,error);
        return NO;
    }
    NSDictionary *videoSetting = @{
        AVVideoCodecKey:AVVideoCodecTypeH264,
        AVVideoWidthKey:@(CVPixelBufferGetWidth(self.buffer)),
        AVVideoHeightKey:@(CVPixelBufferGetHeight(self.buffer))
    };
    AVAssetWriterInput *writerInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:videoSetting];
    AVAssetWriterInputPixelBufferAdaptor *adaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] initWithAssetWriterInput:writerInput sourcePixelBufferAttributes:nil];
    if (![videoWriter canAddInput:writerInput]) {
        return NO;
    }
    [videoWriter addInput:writerInput];
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];
    CMTime presentTime = CMTimeMake(0, 600);
    while (1) {
        if ([writerInput isReadyForMoreMediaData]) {
            [adaptor appendPixelBuffer:self.buffer withPresentationTime:presentTime];
            [writerInput markAsFinished];
            block BOOL isFinish = NO;
            dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
            [videoWriter finishWritingWithCompletionHandler:^{
                isFinish = YES;
                dispatch_semaphore_signal(semaphore);
            }];
            dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, 2.0f * NSEC_PER_SEC);
            dispatch_semaphore_wait(semaphore, time);
            if (!isFinish) {
                Log(@"%s create video error",PRETTY_FUNCTION__);
            }
            break;
        }
    }
    return YES;
}

0

Answer 3

Media Engineer OP

Apple

Dec ’20

That looks straightforward. When you get this error, are there any other apps on the phone doing media-related work?

0

Answer 4

Onion_Shen OP

Dec ’20

no, just my app

0

Answer 5

Onion_Shen OP

Dec ’20

i call the saveVideo function use dispatchasync which in a serial queue,the dispatchsemaphore_wait will call due to timeout,and the status of videoWriter is AVAssetWriterStatusWriting

0