#import "PGVideoMovie.h"
#import "GPUImageFilter.h"

GLfloat kColorConversion601Default[] = {
    1.164,  1.164, 1.164,
    0.0, -0.392, 2.017,
    1.596, -0.813,   0.0,
};

GLfloat kColorConversion601FullRangeDefault[] = {
    1.0,    1.0,    1.0,
    0.0,    -0.343, 1.765,
    1.4,    -0.711, 0.0,
};

GLfloat kColorConversion709Default[] = {
      1,       1,       1,
      0, -.21482, 2.12798,
    1.28033, -.38059,       0,
};

GLfloat *kColorConversion601 = kColorConversion601Default;
GLfloat *kColorConversion601FullRange = kColorConversion601FullRangeDefault;
GLfloat *kColorConversion709 = kColorConversion709Default;

NSString *const kYUVVideoRangeConversionForRGFragmentShaderString = SHADER_STRING
(
 varying highp vec2 texCoord;
 
 uniform sampler2D luminanceTexture;
 uniform sampler2D chrominanceTexture;
 uniform mediump mat3 colorConversionMatrix;
 
 void main()
 {
     mediump vec3 yuv;
     lowp vec3 rgb;
     
     yuv.x = texture2D(luminanceTexture, texCoord).r;
     yuv.yz = texture2D(chrominanceTexture, texCoord).rg - vec2(0.5, 0.5);
     rgb = colorConversionMatrix * yuv;
     
     gl_FragColor = vec4(rgb, 1);
 }
 );

NSString *const kYUVFullRangeConversionForLAFragmentShaderString = SHADER_STRING
(
 varying highp vec2 texCoord;
 
 uniform sampler2D luminanceTexture;
 uniform sampler2D chrominanceTexture;
 uniform mediump mat3 colorConversionMatrix;
 
 void main()
 {
     mediump vec3 yuv;
     lowp vec3 rgb;
     
     yuv.x = texture2D(luminanceTexture, texCoord).r;
     yuv.yz = texture2D(chrominanceTexture, texCoord).ra - vec2(0.5, 0.5);
     rgb = colorConversionMatrix * yuv;
     
     gl_FragColor = vec4(rgb, 1);
 }
 );


NSString *const kYUVVideoRangeConversionForLAFragmentShaderString = SHADER_STRING
(
 varying highp vec2 texCoord;
 
 uniform sampler2D luminanceTexture;
 uniform sampler2D chrominanceTexture;
 uniform mediump mat3 colorConversionMatrix;
 
 void main()
 {
     mediump vec3 yuv;
     lowp vec3 rgb;
     
     yuv.x = texture2D(luminanceTexture, texCoord).r - (16.0/255.0);
     yuv.yz = texture2D(chrominanceTexture, texCoord).ra - vec2(0.5, 0.5);
     rgb = colorConversionMatrix * yuv;
     
     gl_FragColor = vec4(rgb, 1);
 }
);

@interface PGVideoMovie () <AVPlayerItemOutputPullDelegate>
{
    AVAssetReader *reader;
    AVPlayerItemVideoOutput *playerItemOutput;
    CADisplayLink *displayLink;
    CMTime previousFrameTime, processingFrameTime;
    CFAbsoluteTime previousActualFrameTime;
    BOOL keepLooping;

    GLuint luminanceTexture, chrominanceTexture;

    GLProgram *yuvConversionProgram;
    GLint yuvConversionPositionAttribute, yuvConversionTextureCoordinateAttribute;
    GLint yuvConversionLuminanceTextureUniform, yuvConversionChrominanceTextureUniform;
    GLint yuvConversionMatrixUniform;
    const GLfloat *_preferredConversion;
    
    BOOL isFullYUVRange;

    int imageBufferWidth, imageBufferHeight;
}

- (void)processAsset;

@end

@implementation PGVideoMovie
{
    bool videoEncodingIsFinished;
}

@synthesize asset = _asset;
@synthesize shouldRepeat = _shouldRepeat;

#pragma mark -
#pragma mark Initialization and teardown

- (UIInterfaceOrientation)orientationForTrack:(AVAsset *)asset
{
    AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    CGSize size = [videoTrack naturalSize];
    CGAffineTransform txf = [videoTrack preferredTransform];

    if (size.width == txf.tx && size.height == txf.ty)
        return UIInterfaceOrientationLandscapeRight;
    else if (txf.tx == 0 && txf.ty == 0)
        return UIInterfaceOrientationLandscapeLeft;
    else if (txf.tx == 0 && txf.ty == size.width)
        return UIInterfaceOrientationPortraitUpsideDown;
    else
        return UIInterfaceOrientationPortrait;
}

- (instancetype)initWithAsset:(AVAsset *)asset
{
    if (!(self = [super init])) 
    {
      return nil;
    }
    
    [self yuvConversionSetup];

    self.asset = asset;

    return self;
}

- (instancetype)initWithPlayerItem:(AVPlayerItem *)playerItem;
{
    if (!(self = [super init]))
    {
        return nil;
    }

    [self yuvConversionSetup];

    self.playerItem = playerItem;

    return self;
}

- (void)yuvConversionSetup
{
    if ([GPUImageContext supportsFastTextureUpload])
    {
        runSynchronouslyOnVideoProcessingQueue(^{
            [GPUImageContext useImageProcessingContext];

            _preferredConversion = kColorConversion709;
            isFullYUVRange       = YES;
            yuvConversionProgram = [[GPUImageContext sharedImageProcessingContext] programForVertexShaderString:kGPUImageVertexShaderString fragmentShaderString:kYUVVideoRangeConversionForRGFragmentShaderString];

            if (!yuvConversionProgram.initialized)
            {
                [yuvConversionProgram addAttribute:@"position"];
                [yuvConversionProgram addAttribute:@"inputTextureCoordinate"];

                if (![yuvConversionProgram link])
                {
                    NSString *progLog = [yuvConversionProgram programLog];
                    NSLog(@"Program link log: %@", progLog);
                    NSString *fragLog = [yuvConversionProgram fragmentShaderLog];
                    NSLog(@"Fragment shader compile log: %@", fragLog);
                    NSString *vertLog = [yuvConversionProgram vertexShaderLog];
                    NSLog(@"Vertex shader compile log: %@", vertLog);
                    yuvConversionProgram = nil;
                    NSAssert(NO, @"Filter shader link failed");
                }
            }

            yuvConversionPositionAttribute = [yuvConversionProgram attributeIndex:@"position"];
            yuvConversionTextureCoordinateAttribute = [yuvConversionProgram attributeIndex:@"inputTextureCoordinate"];
            yuvConversionLuminanceTextureUniform = [yuvConversionProgram uniformIndex:@"luminanceTexture"];
            yuvConversionChrominanceTextureUniform = [yuvConversionProgram uniformIndex:@"chrominanceTexture"];
            yuvConversionMatrixUniform = [yuvConversionProgram uniformIndex:@"colorConversionMatrix"];

            [GPUImageContext setActiveShaderProgram:yuvConversionProgram];

            glEnableVertexAttribArray(yuvConversionPositionAttribute);
            glEnableVertexAttribArray(yuvConversionTextureCoordinateAttribute);
        });
    }
}

- (void)dealloc
{
    [playerItemOutput setDelegate:nil queue:nil];
    
    if (self.playerItem && (displayLink != nil))
    {
        [displayLink invalidate];
        displayLink = nil;
    }
}

#pragma mark -
#pragma mark Movie processing

//- (void)enableSynchronizedEncodingUsingMovieWriter:(GPUImageMovieWriter *)movieWriter;
//{
//    synchronizedMovieWriter = movieWriter;
//    movieWriter.encodingLiveVideo = NO;
//}

- (void)startProcessing
{
    if (_shouldRepeat) self->keepLooping = true;
    
    if (self.playerItem != nil) {
        [self processPlayerItem];
    } else {
        [self processAsset];
    }
}

- (AVAssetReader*)createAssetReader
{
    NSError *error = nil;
    AVAssetReader *assetReader = [AVAssetReader assetReaderWithAsset:self.asset error:&error];
    
    NSMutableDictionary *outputSettings = [NSMutableDictionary dictionary];
    if ([GPUImageContext supportsFastTextureUpload]) {
        [outputSettings setObject:@(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) forKey:(id)kCVPixelBufferPixelFormatTypeKey];
        isFullYUVRange = YES;
    }
    else {
        [outputSettings setObject:@(kCVPixelFormatType_32BGRA) forKey:(id)kCVPixelBufferPixelFormatTypeKey];
        isFullYUVRange = NO;
    }
    
    AVAssetReaderTrackOutput *readerVideoTrackOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:[[self.asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] outputSettings:outputSettings];
    readerVideoTrackOutput.alwaysCopiesSampleData = false;
    [assetReader addOutput:readerVideoTrackOutput];

    return assetReader;
}

- (void)processAsset
{
    reader = [self createAssetReader];

    AVAssetReaderOutput *readerVideoTrackOutput = nil;
    
    for (AVAssetReaderOutput *output in reader.outputs) {
        if( [output.mediaType isEqualToString:AVMediaTypeVideo] ) {
            readerVideoTrackOutput = output;
        }
    }

    if (![reader startReading])  {
        return;
    }

    __unsafe_unretained PGVideoMovie *weakSelf = self;

    while (reader.status == AVAssetReaderStatusReading && (!_shouldRepeat || keepLooping))
    {
        [weakSelf readNextVideoFrameFromOutput:readerVideoTrackOutput];
    }

    if (reader.status == AVAssetReaderStatusCompleted) {
            
        [reader cancelReading];

        if (keepLooping) {
            reader = nil;
            [self startProcessing];
        } else {
            [weakSelf endProcessing];
        }

    }
}

- (void)processPlayerItem
{
    dispatch_sync(dispatch_get_main_queue(), ^{
        displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(displayLinkCallback:)];
        [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
        [displayLink setPaused:true];
    });

    
    runSynchronouslyOnVideoProcessingQueue(^{
        dispatch_queue_t videoProcessingQueue = [GPUImageContext sharedContextQueue];
        NSMutableDictionary *pixBuffAttributes = [NSMutableDictionary dictionary];
        if ([GPUImageContext supportsFastTextureUpload]) {
            [pixBuffAttributes setObject:@(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) forKey:(id)kCVPixelBufferPixelFormatTypeKey];
        }
        else {
            [pixBuffAttributes setObject:@(kCVPixelFormatType_32BGRA) forKey:(id)kCVPixelBufferPixelFormatTypeKey];
        }
        playerItemOutput = [[AVPlayerItemVideoOutput alloc] initWithPixelBufferAttributes:pixBuffAttributes];
        [playerItemOutput setDelegate:self queue:videoProcessingQueue];

        [_playerItem addOutput:playerItemOutput];
        [playerItemOutput requestNotificationOfMediaDataChangeWithAdvanceInterval:0.1];
    });
}

- (void)outputMediaDataWillChange:(AVPlayerItemOutput *)sender
{
	[displayLink setPaused:false];
}

- (void)displayLinkCallback:(CADisplayLink *)sender
{
	CFTimeInterval nextVSync = ([sender timestamp] + [sender duration]);
	CMTime outputItemTime = [playerItemOutput itemTimeForHostTime:nextVSync];
    [self processPixelBufferAtTime:outputItemTime];
}

- (void)processPixelBufferAtTime:(CMTime)outputItemTime
{
    if ([playerItemOutput hasNewPixelBufferForItemTime:outputItemTime])
    {
        __unsafe_unretained PGVideoMovie *weakSelf = self;
        CVPixelBufferRef pixelBuffer = [playerItemOutput copyPixelBufferForItemTime:outputItemTime itemTimeForDisplay:NULL];
        if (pixelBuffer != NULL)
        {
            runSynchronouslyOnVideoProcessingQueue(^{
                [weakSelf processMovieFrame:pixelBuffer withSampleTime:outputItemTime];
                CFRelease(pixelBuffer);
            });
        }
    }
}

- (BOOL)readNextVideoFrameFromOutput:(AVAssetReaderOutput *)readerVideoTrackOutput;
{
    if (reader.status == AVAssetReaderStatusReading && !videoEncodingIsFinished)
    {
        CMSampleBufferRef sampleBufferRef = [readerVideoTrackOutput copyNextSampleBuffer];
        if (sampleBufferRef) 
        {
            CMTime currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBufferRef);
            CMTime differenceFromLastFrame = CMTimeSubtract(currentSampleTime, previousFrameTime);
            CFAbsoluteTime currentActualTime = CFAbsoluteTimeGetCurrent();
            
            CGFloat frameTimeDifference = CMTimeGetSeconds(differenceFromLastFrame);
            CGFloat actualTimeDifference = currentActualTime - previousActualFrameTime;
            
            if (frameTimeDifference > actualTimeDifference)
            {
                usleep(1000000.0 * (frameTimeDifference - actualTimeDifference));
            }
            
            previousFrameTime = currentSampleTime;
            previousActualFrameTime = CFAbsoluteTimeGetCurrent();

            __unsafe_unretained PGVideoMovie *weakSelf = self;
            runSynchronouslyOnVideoProcessingQueue(^{
                [weakSelf processMovieFrame:sampleBufferRef];
                CMSampleBufferInvalidate(sampleBufferRef);
                CFRelease(sampleBufferRef);
            });

            return true;
        }
        else
        {
            if (!keepLooping) {
                videoEncodingIsFinished = true;
                if (videoEncodingIsFinished)
                    [self endProcessing];
            }
        }
    }
    return false;
}


- (void)processMovieFrame:(CMSampleBufferRef)movieSampleBuffer; 
{
    CMTime currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(movieSampleBuffer);
    CVImageBufferRef movieFrame = CMSampleBufferGetImageBuffer(movieSampleBuffer);

    processingFrameTime = currentSampleTime;
    [self processMovieFrame:movieFrame withSampleTime:currentSampleTime];
}

- (CGFloat)progress
{
    if (AVAssetReaderStatusReading == reader.status)
    {
        float current = processingFrameTime.value * 1.0f / processingFrameTime.timescale;
        float duration = self.asset.duration.value * 1.0f / self.asset.duration.timescale;
        return current / duration;
    }
    else if ( AVAssetReaderStatusCompleted == reader.status )
    {
        return 1.f;
    }
    else
    {
        return 0.f;
    }
}

- (void)processMovieFrame:(CVPixelBufferRef)movieFrame withSampleTime:(CMTime)currentSampleTime
{
    int bufferHeight = (int) CVPixelBufferGetHeight(movieFrame);
    int bufferWidth = (int) CVPixelBufferGetWidth(movieFrame);

    CFTypeRef colorAttachments = CVBufferGetAttachment(movieFrame, kCVImageBufferYCbCrMatrixKey, NULL);
    if (colorAttachments != NULL)
    {
        if (CFStringCompare(colorAttachments, kCVImageBufferYCbCrMatrix_ITU_R_601_4, 0) == kCFCompareEqualTo)
        {
            if (isFullYUVRange)
            {
                _preferredConversion = kColorConversion601FullRange;
            }
            else
            {
                _preferredConversion = kColorConversion601;
            }
        }
        else
        {
            _preferredConversion = kColorConversion709;
        }
    }
    else
    {
        if (isFullYUVRange)
        {
            _preferredConversion = kColorConversion601FullRange;
        }
        else
        {
            _preferredConversion = kColorConversion601;
        }

    }

    [GPUImageContext useImageProcessingContext];
    
    if ([GPUImageContext supportsFastTextureUpload])
    {
        CVOpenGLESTextureRef luminanceTextureRef = NULL;
        CVOpenGLESTextureRef chrominanceTextureRef = NULL;

        if (CVPixelBufferGetPlaneCount(movieFrame) > 0)
        {
            CVPixelBufferLockBaseAddress(movieFrame,0);
        
            if ((imageBufferWidth != bufferWidth) && (imageBufferHeight != bufferHeight))
            {
                imageBufferWidth = bufferWidth;
                imageBufferHeight = bufferHeight;
            }

            CVReturn err;
            // Y-plane
            glActiveTexture(GL_TEXTURE4);
            if ([GPUImageContext deviceSupportsRedTextures])
            {
                err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache], movieFrame, NULL, GL_TEXTURE_2D, GL_RED_EXT, bufferWidth, bufferHeight, GL_RED_EXT, GL_UNSIGNED_BYTE, 0, &luminanceTextureRef);
            }
            else
            {
                err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache], movieFrame, NULL, GL_TEXTURE_2D, GL_LUMINANCE, bufferWidth, bufferHeight, GL_LUMINANCE, GL_UNSIGNED_BYTE, 0, &luminanceTextureRef);
            }
            if (err)
            {
                NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
            }

            luminanceTexture = CVOpenGLESTextureGetName(luminanceTextureRef);

            glBindTexture(GL_TEXTURE_2D, luminanceTexture);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

            // UV-plane
            glActiveTexture(GL_TEXTURE5);
            if ([GPUImageContext deviceSupportsRedTextures])
            {
                err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache], movieFrame, NULL, GL_TEXTURE_2D, GL_RG_EXT, bufferWidth/2, bufferHeight/2, GL_RG_EXT, GL_UNSIGNED_BYTE, 1, &chrominanceTextureRef);
            }
            else
            {
                err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache], movieFrame, NULL, GL_TEXTURE_2D, GL_LUMINANCE_ALPHA, bufferWidth/2, bufferHeight/2, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, 1, &chrominanceTextureRef);
            }
            if (err)
            {
                NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
            }

            chrominanceTexture = CVOpenGLESTextureGetName(chrominanceTextureRef);

            glBindTexture(GL_TEXTURE_2D, chrominanceTexture);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

            [self convertYUVToRGBOutput];

            for (id<GPUImageInput> currentTarget in targets)
            {
                NSInteger indexOfObject = [targets indexOfObject:currentTarget];
                NSInteger targetTextureIndex = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue];
                [currentTarget setInputSize:CGSizeMake(bufferWidth, bufferHeight) atIndex:targetTextureIndex];
                [currentTarget setInputFramebuffer:outputFramebuffer atIndex:targetTextureIndex];
                
                AVAsset *asset = self.asset;
                if (asset == nil) {
                    asset = self.playerItem.asset;
                }
                if (asset != nil) {
                    UIInterfaceOrientation orientation = [self orientationForTrack:asset];
                    if (orientation == UIInterfaceOrientationPortrait) {
                        [currentTarget setInputRotation:kGPUImageRotateRight atIndex:targetTextureIndex];
                    } else if (orientation == UIInterfaceOrientationLandscapeRight) {
                        [currentTarget setInputRotation:kGPUImageRotate180 atIndex:targetTextureIndex];
                    } else if (orientation == UIInterfaceOrientationPortraitUpsideDown) {
                        [currentTarget setInputRotation:kGPUImageRotateLeft atIndex:targetTextureIndex];
                    }
                }
            }
            
            [outputFramebuffer unlock];

            for (id<GPUImageInput> currentTarget in targets)
            {
                NSInteger indexOfObject = [targets indexOfObject:currentTarget];
                NSInteger targetTextureIndex = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue];
                [currentTarget newFrameReadyAtTime:currentSampleTime atIndex:targetTextureIndex];
            }

            CVPixelBufferUnlockBaseAddress(movieFrame, 0);
            CFRelease(luminanceTextureRef);
            CFRelease(chrominanceTextureRef);
        }
    }
    else
    {
        CVPixelBufferLockBaseAddress(movieFrame, 0);
        
        outputFramebuffer = [[GPUImageContext sharedFramebufferCache] fetchFramebufferForSize:CGSizeMake(bufferWidth, bufferHeight) textureOptions:self.outputTextureOptions onlyTexture:YES];

        glBindTexture(GL_TEXTURE_2D, [outputFramebuffer texture]);
        
        glTexImage2D(GL_TEXTURE_2D, 0, self.outputTextureOptions.internalFormat, bufferWidth, bufferHeight, 0, self.outputTextureOptions.format, self.outputTextureOptions.type, CVPixelBufferGetBaseAddress(movieFrame));
        
        for (id<GPUImageInput> currentTarget in targets)
        {
            NSInteger indexOfObject = [targets indexOfObject:currentTarget];
            NSInteger targetTextureIndex = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue];
            [currentTarget setInputSize:CGSizeMake(bufferWidth, bufferHeight) atIndex:targetTextureIndex];
            [currentTarget setInputFramebuffer:outputFramebuffer atIndex:targetTextureIndex];
        }
        
        [outputFramebuffer unlock];
        
        for (id<GPUImageInput> currentTarget in targets)
        {
            NSInteger indexOfObject = [targets indexOfObject:currentTarget];
            NSInteger targetTextureIndex = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue];
            [currentTarget newFrameReadyAtTime:currentSampleTime atIndex:targetTextureIndex];
        }
        CVPixelBufferUnlockBaseAddress(movieFrame, 0);
    }
}

- (void)endProcessing
{
    keepLooping = NO;

    [displayLink setPaused:YES];

    for (id<GPUImageInput> currentTarget in targets)
    {
        [currentTarget endProcessing];
    }
    
    if (displayLink != nil)
    {
        [displayLink invalidate];
        displayLink = nil;
    }
}

- (void)cancelProcessing
{
    if (reader) {
        [reader cancelReading];
    }
    [self endProcessing];
}

- (void)convertYUVToRGBOutput;
{
    [GPUImageContext setActiveShaderProgram:yuvConversionProgram];
    outputFramebuffer = [[GPUImageContext sharedFramebufferCache] fetchFramebufferForSize:CGSizeMake(imageBufferWidth, imageBufferHeight) onlyTexture:NO];
    [outputFramebuffer activateFramebuffer];

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    static const GLfloat squareVertices[] = {
        -1.0f, -1.0f,
        1.0f, -1.0f,
        -1.0f,  1.0f,
        1.0f,  1.0f,
    };

    static const GLfloat textureCoordinates[] = {
        0.0f, 0.0f,
        1.0f, 0.0f,
        0.0f, 1.0f,
        1.0f, 1.0f,
    };

	glActiveTexture(GL_TEXTURE4);
	glBindTexture(GL_TEXTURE_2D, luminanceTexture);
	glUniform1i(yuvConversionLuminanceTextureUniform, 4);

    glActiveTexture(GL_TEXTURE5);
	glBindTexture(GL_TEXTURE_2D, chrominanceTexture);
	glUniform1i(yuvConversionChrominanceTextureUniform, 5);

    glUniformMatrix3fv(yuvConversionMatrixUniform, 1, GL_FALSE, _preferredConversion);

    glVertexAttribPointer(yuvConversionPositionAttribute, 2, GL_FLOAT, 0, 0, squareVertices);
	glVertexAttribPointer(yuvConversionTextureCoordinateAttribute, 2, GL_FLOAT, 0, 0, textureCoordinates);

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}

- (AVAssetReader*)assetReader {
    return reader;
}

- (BOOL)videoEncodingIsFinished {
    return videoEncodingIsFinished;
}

@end