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我正在尝试使用 AVAssetWriter 创建一个包含大约 20 个图像的 MPEG4 ..

对于 10 张图片，我可以在我的 app 目录中创建一个文件，但是对于 20 张图片，我无法创建一个文件。

这是我尝试保存图像 mpeg4 格式文件的路径（设备路径）：

var/mobile/Applications/FED8E776-92CC-47BC-AA47-845DAED5CBE7/Library/Caches/videoOutput1234videoOutput1234.mp4

这里我的问题是：在应用程序目录中创建的文件夹是否有任何限制，如果有，限制是什么以及如何找到创建文件的大小

这是我的代码：

-(void)writeImageAsMovie:(NSMutableArray *)array toPath:(NSString*)path size:(CGSize)size duration:(int)duration 
{
CFDataRef imgData;
CGDataProviderRef imgDataProvider;
CGImageRef image1;




if ([[NSFileManager defaultManager] fileExistsAtPath:path])
    [[NSFileManager defaultManager] removeItemAtPath:path error:nil];


NSError *error = nil;

AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:path] fileType:AVFileTypeMPEG4 error:&error];


NSParameterAssert(videoWriter);

NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:size.width], AVVideoWidthKey,
                               [NSNumber numberWithInt:size.height], AVVideoHeightKey,
                               nil];
AVAssetWriterInput* writerInput = [[AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings] retain];


AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput sourcePixelBufferAttributes:nil];


NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);

writerInput.expectsMediaDataInRealTime = YES;
[videoWriter addInput:writerInput];


[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];


CVPixelBufferRef buffer = NULL;


int frameCount = 0;

for(int i = 0; i<[array count]; i++)
{
    imgData = (CFDataRef)[array objectAtIndex:i];
    imgDataProvider = CGDataProviderCreateWithCFData (imgData);
    image1 = CGImageCreateWithPNGDataProvider(imgDataProvider, NULL, true, kCGRenderingIntentDefault);

    buffer = [self pixelBufferFromCGImage:image1];

    BOOL append_ok = NO;
    int j = 0;
    while (!append_ok && j < 30) 
    {
        if (adaptor.assetWriterInput.readyForMoreMediaData) 
        {
            printf("appending %d attemp %d\n", frameCount, j);
            CMTime frameTime;


            int64_t value = [[dataBaseTimeArray objectAtIndex:i] intValue];
            int32_t preferredTimeScale = 1;
            frameTime = CMTimeMake(value, preferredTimeScale);


            append_ok = [adaptor appendPixelBuffer:buffer withPresentationTime:frameTime];
                            }
        } 
        else 
        {
            printf("adaptor not ready %d, %d\n", frameCount, j);
            [NSThread sleepForTimeInterval:0.1];
        }
        j++;
    }
    if (!append_ok) {
        printf("error appending image %d times %d\n", frameCount, j);
    }
    frameCount++;
    CVBufferRelease(buffer);
}

if (AVAssetWriterStatusCompleted) {
    [writerInput markAsFinished];
    [videoWriter finishWriting];
}
}
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