使用AVAssetWriter从图像创建电影在3GS设备上无法正常工作

问题描述

对appendPixelBuffer的调用在3GS设备（IOS 4.1）上返回NO，但在iPhone 4设备上运行良好。

以下对appendPixelBuffer的调用是问题的根源：

  CVPixelBufferRef buffer = NULL; 
 buffer = [self pixelBufferFromCGImage：[[UIImage imageNamed：@frame1.png] CGImage]]; 
 BOOL result = [adapter appendPixelBuffer：buffer withPresentationTime：kCMTimeZero]; 
 
如果（结果==否）//在3GS上失败，但在iphone 4上工作
 NSLog（@无法附加缓冲区）; 
  

}

完整代码：

   - （void）writeImagesAsMovie：（NSArray *）数组toPath：（NSString *）path {
 
 
 NSLog（路径）; 
 
 NSError * error = nil; 
 AVAssetWriter * videoWriter = [[AVAssetWriter alloc] initWithURL：
 [NSURL fileURLWithPath：path] fileType：AVFileTypeQuickTimeMovie 
 error：& error]; 
 
 if（error）{
 NSLog（@创建AssetWriter的错误：％@，[错误描述]）; 
} 
  

错误（仅限3GS，iphone 4正常）是

  NSDictionary * videoSettings = [NSDictionary dictionaryWithObjectsAndKeys：
 AVVideoCodecH264，AVVideoCodecKey，
 [NSNumber numberWithInt：frameSize.width]，AVVideoWidthKey，
 [NSNumber numberWithInt：frameSize.height]，AVVideoHeightKey，
 nil]; 
 
 
 
 AVAssetWriterInput * writerInput = [[AVAssetWriterInput 
 assetWriterInputWithMediaType：AVMediaTypeVideo 
 outputSettings：videoSettings] retain]; 
 
 NSMutableDictionary * attributes = [[NSMutableDictionary alloc] init]; 
 [attributes setObject：[NSNumber numberWithUnsignedInt：kCVPixelFormatType_32ARGB] forKey：（NSString *）kCVPixelBufferPixelFormatTypeKey]; 
 [attributes setObject：[NSNumber numberWithUnsignedInt：frameSize.width] forKey：（NSString *）kCVPixelBufferWidthKey]; 
 [属性setObject：[NSNumber numberWithUnsignedInt：frameSize.height] forKey：（NSString *）kCVPixelBufferHeightKey]; 
 
 AVAssetWriterInputPixelBufferAdaptor * adapter = [AVAssetWriterInputPixelBufferAdaptor 
 assetWriterInputPixelBufferAdaptorWithAssetWriterInput：writerInput 
 sourcePixelBufferAttributes：attributes]; 
 
 [videoWriter addInput：writerInput]; 
 
 //修复所有错误
 writerInput.expectsMediaDataInRealTime = YES; 
 
 //开始一个会话：
 BOOL start = [videoWriter startWriting]; 
 NSLog（@会话开始？％d，开始）; 
 
 [videoWriter startSessionAtSourceTime：kCMTimeZero]; 
 
 CVPixelBufferRef buffer = NULL; 
 buffer = [self pixelBufferFromCGImage：[[UIImage imageNamed：@frame1.png] CGImage]]; 
 BOOL result = [adapter appendPixelBuffer：buffer withPresentationTime：kCMTimeZero]; 
 
如果（结果==否）//在3GS上失败，但在iphone 4上工作
 NSLog（@无法附加缓冲区）; 
 
 if（buffer）
 CVBufferRelease（buffer）; 
 
 [NSThread sleepForTimeInterval：0.05]; 
 // for（int i = 1; i< [array count]; i ++）
 for（int i = 1; i< 20; i ++）
 {
 if（ adaptor.assetWriterInput.readyForMoreMediaData）
 {
 NSLog（@inside for loop％d，i）; 
 CMTime frameTime = CMTimeMake（1,15）; 
 CMTime lastTime = CMTimeMake（i，15）; 
 CMTime presentTime = CMTimeAdd（lastTime，frameTime）; 
 NSString * imgName = [NSString stringWithFormat：@frame％d.png，i]; 
 UIImage * imgFrame = [UIImage imageNamed：imgName]; 
 buffer = [self pixelBufferFromCGImage：[imgFrame CGImage]]; 
 BOOL result = [adapter appendPixelBuffer：buffer withPresentationTime：presentTime]; 
 
如果（结果==否）//在3GS上失败，但在iphone 4上工作
 {
 NSLog（@无法附加缓冲区）; 
 NSLog（@错误是％@，[videoWriter错误]）; 
} 
 if（buffer）
 CVBufferRelease（buffer）; 
 [NSThread sleepForTimeInterval：0.05]; 
} 
其他
 {
 NSLog（@错误）; 
 i--; 
} 
} 
 
 //完成会话：
 [writerInput markAsFinished]; 
 [videoWriter finishWriting]; 
 CVPixelBufferPoolRelease（adaptor.pixelBufferPool）; 
 [videoWriter release]; 
 [writerInput release]; 
 
 NSLog（@电影创建成功）; 
 
} 
 
  - （CVPixelBufferRef）pixelBufferFromCGImage：（CGImageRef）image 
 {
 NSDictionary * options = [NSDictionary dictionaryWithObjectsAndKeys：
 [NSNumber] numberWithBool：YES]，kCVPixelBufferCGImageCompatibilityKey，
 [NSNumber numberWithBool：YES]，kCVPixelBufferCGBitmapContextCompatibilityKey，
 nil]; 
 CVPixelBufferRef pxbuffer = NULL; 
 
 CVPixelBufferCreate（kCFAllocatorDefault，self.view.frame.size.width，
 self.view.frame.size.height，kCVPixelFormatType_32ARGB，（CFDictionaryRef）选项，
& pxbuffer ）; 
 
 CVPixelBufferLockBaseAddress（pxbuffer，0）; 
 void * pxdata = CVPixelBufferGetBaseAddress（pxbuffer）; 
 
 CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB（）; 
 CGContextRef context = CGBitmapContextCreate（pxdata，self.view.frame.size.width，
 self.view.frame.size.height，8,4 * self.view.frame.size.width，rgbColorSpace ，
 kCGImageAlphaNoneSkipFirst）; 
 
 CGContextConcatCTM（context，CGAffineTransformMakeRotation（0））; 
 CGContextDrawImage（context，CGRectMake（0,0，CGImageGetWidth（image），
 CGImageGetHeight（image）），image）; 
 CGColorSpaceRelease（rgbColorSpace）; 
 CGContextRelease（context）; 
 
 CVPixelBufferUnlockBaseAddress（pxbuffer，0）; 
 
返回pxbuffer; 
} 
  

解决方案

使用此。 / p>

The call to appendPixelBuffer is returning NO on 3GS device (IOS 4.1), but is working well on iPhone 4 devices.

The following call to appendPixelBuffer is the source of the problem:

CVPixelBufferRef buffer = NULL;
buffer = [self pixelBufferFromCGImage:[[UIImage imageNamed:@"frame1.png"] CGImage]];
BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

if (result == NO) //failes on 3GS, but works on iphone 4
    NSLog(@"failed to append buffer");

}

Full Code:

-(void)writeImagesAsMovie:(NSArray *)array toPath:(NSString*)path {


NSLog(path);

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

if(error) {
    NSLog(@"error creating AssetWriter: %@",[error description]);
}

The error (ONLY ON 3GS, iphone 4 is fine) is

NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:frameSize.width], AVVideoWidthKey,
                               [NSNumber numberWithInt:frameSize.height], AVVideoHeightKey,
                               nil];



AVAssetWriterInput* writerInput = [[AVAssetWriterInput
                                    assetWriterInputWithMediaType:AVMediaTypeVideo
                                    outputSettings:videoSettings] retain];

NSMutableDictionary *attributes = [[NSMutableDictionary alloc]init];
[attributes setObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32ARGB] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];

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

[videoWriter addInput:writerInput];

// fixes all errors
writerInput.expectsMediaDataInRealTime = YES;

//Start a session:
BOOL start = [videoWriter startWriting];
NSLog(@"Session started? %d", start);

[videoWriter startSessionAtSourceTime:kCMTimeZero];

CVPixelBufferRef buffer = NULL;
buffer = [self pixelBufferFromCGImage:[[UIImage imageNamed:@"frame1.png"] CGImage]];
BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

if (result == NO) //failes on 3GS, but works on iphone 4
    NSLog(@"failed to append buffer");

if(buffer)
    CVBufferRelease(buffer);

[NSThread sleepForTimeInterval:0.05];
//for (int i = 1;i<[array count]; i++)
for (int i = 1;i<20; i++)
{
    if (adaptor.assetWriterInput.readyForMoreMediaData)
    {
        NSLog(@"inside for loop %d",i);
        CMTime frameTime = CMTimeMake(1, 15);
        CMTime lastTime=CMTimeMake(i, 15);
        CMTime presentTime=CMTimeAdd(lastTime, frameTime);
        NSString *imgName = [NSString stringWithFormat:@"frame%d.png",i];
        UIImage *imgFrame = [UIImage imageNamed:imgName] ;
        buffer = [self pixelBufferFromCGImage:[imgFrame CGImage]];
        BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];

        if (result == NO) //failes on 3GS, but works on iphone 4
        {
            NSLog(@"failed to append buffer");
            NSLog(@"The error is %@", [videoWriter error]);
        }
        if(buffer)
            CVBufferRelease(buffer);
        [NSThread sleepForTimeInterval:0.05];
    }
    else
    {
        NSLog(@"error");
        i--;
    }
}

//Finish the session:
[writerInput markAsFinished];
[videoWriter finishWriting];
CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
[videoWriter release];
[writerInput release];

NSLog(@"Movie created successfully");

}

- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image
{
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                             nil];
    CVPixelBufferRef pxbuffer = NULL;

    CVPixelBufferCreate(kCFAllocatorDefault, self.view.frame.size.width,
                        self.view.frame.size.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options,
                        &pxbuffer);

    CVPixelBufferLockBaseAddress(pxbuffer, 0);
    void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(pxdata, self.view.frame.size.width,
                                                 self.view.frame.size.height, 8, 4*self.view.frame.size.width, rgbColorSpace,
                                                 kCGImageAlphaNoneSkipFirst);

    CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
    CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
                                           CGImageGetHeight(image)), image);
    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

解决方案

use this https://github.com/caferrara/img-to-video it runs on iPhone 3gs device.

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