He leído todas las publicaciones que puedo encontrar en Internet sobre esta función, y tengo cierto éxito para crear el archivo de video, pero tengo 3 problemas restantes y parece que nadie lo ha mencionado.

Tengo 3 problemas:

el video no se puede reproducir correctamente en algunos reproductores: quicktime (ventana), el video se reproduce solo por un fotograma y la pantalla se vuelve blanca, y el video no se puede reproducir en youtube.

algunas imágenes, por alguna razón, la imagen es muy anormal

http: //lh3.googleusercontent.com/-Jyz-L1k3MEk/TjpfSfKf8LI/AAAAAAAADBs/D1GYuEqI-Oo/h301/1.JP (ok, dicen que soy un usuario nuevo y no me permiten publicar imágenes en la publicación).

algunas imágenes, por alguna razón, la orientación no es correcta, incluso si transformé el contexto de acuerdo con la orientación, todavía no funciona.

¡¿Puede alguien ayudarme en esto por favor, muchas gracias de antemano!

Aquí está mi código:

1: use esta función para crear video con UIImage, solo usé una imagen y 1 archivo de audio (caf), y quiero mostrar esa imagen mientras reproduzco ese audio.

- (void)writeImageAndAudioAsMovie:(UIImage*)image andAudio:(NSString *)audioFilePath duration:(int)duration {
    NSLog(@"start make movie: length:%d",duration);
    NSError *error = nil;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:ImageVideoPath] fileType:AVFileTypeMPEG4
                                                          error:&error];
    NSParameterAssert(videoWriter);
    if ([[NSFileManager defaultManager] fileExistsAtPath:ImageVideoPath]) 
        [[NSFileManager defaultManager] removeItemAtPath:ImageVideoPath error:nil];

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:image.size.width],AVVideoWidthKey,[NSNumber numberWithInt:image.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 setShouldOptimizeForNetworkUse:YES];
    [videoWriter addInput:writerInput];

    //Start a session:
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];

    //Write samples:
    CVPixelBufferRef buffer = [self pixelBufferFromCGImage:image.CGImage];
    [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

    //Finish the session:
    [videoWriter endSessionAtSourceTime:CMTimeMake(duration, 1)];
    [writerInput markAsFinished];
    [videoWriter finishWriting];

    CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
    [videoWriter release];
    [writerInput release];
    [self addAudioToFileAtPath:ImageVideoPath andAudioPath:audioFilePath];
}

2. Cree CVPixelBufferRef para el video

-(CVPixelBufferRef)pixelBufferFromCGImage: (CGImageRef) image{
    float width = CGImageGetWidth(cgimage);
    float height = CGImageGetHeight(cgimage);

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                         nil];
    CVPixelBufferRef pxbuffer = NULL;
    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, width,height, kCVPixelFormatType_32ARGB,(CFDictionaryRef)options,&pxbuffer);

    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);

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

    NSParameterAssert(pxdata != NULL);

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(pxdata,width,height,8,4*width,rgbColorSpace,kCGImageAlphaNoneSkipFirst);

    NSParameterAssert(context);
    CGContextDrawImage(context, CGRectMake(0, 0,width, height), cgimage);

    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

3. juntar video y audio

-(void) addAudioToFileAtPath:(NSString *)vidoPath andAudioPath:(NSString *)audioPath{
    AVMutableComposition* mixComposition = [AVMutableComposition composition];

    NSURL* audio_inputFileUrl = [NSURL fileURLWithPath:audioPath];
    NSURL* video_inputFileUrl = [NSURL fileURLWithPath:vidoPath];

    NSString *outputFilePath = FinalVideoPath;
    NSURL* outputFileUrl = [NSURL fileURLWithPath:outputFilePath];

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

    AVURLAsset* audioAsset = [[AVURLAsset alloc]initWithURL:audio_inputFileUrl options:nil];
    CMTimeRange audio_timeRange = CMTimeRangeMake(kCMTimeZero, audioAsset.duration);
    AVMutableCompositionTrack *b_compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    [b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];


    AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:video_inputFileUrl options:nil];
    CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero,videoAsset.duration);
    AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
    [a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];

    //nextClipStartTime = CMTimeAdd(nextClipStartTime, a_timeRange.duration);
    [audioAsset release];audioAsset = nil;
    [videoAsset release];videoAsset = nil;

    AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];   
    _assetExport.outputFileType = AVFileTypeQuickTimeMovie;
    _assetExport.outputURL = outputFileUrl;

    [_assetExport exportAsynchronouslyWithCompletionHandler:
     ^(void ) {
         switch (_assetExport.status) 
         {
             case AVAssetExportSessionStatusCompleted:
                 //export complete 
                 NSLog(@"Export Complete");
                 break;
             case AVAssetExportSessionStatusFailed:
                 NSLog(@"Export Failed");
                 NSLog(@"ExportSessionError: %@", [_assetExport.error localizedDescription]);
             //export error (see exportSession.error)  
                 break;
             case AVAssetExportSessionStatusCancelled:
                 NSLog(@"Export Failed");
                 NSLog(@"ExportSessionError: %@", [_assetExport.error localizedDescription]);
                 //export cancelled  
                 break;
         }
      }];    
}