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A basic AVAssetReader/AVAssetWriter setup produces full color range video (yuvj420p(pc, bt709)) on iOS 14.3 and TV range video (yuv420p(tv, bt709)) on iOS 14.1. Is this expected behavior, and if so, is there a way to control this?

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    AVAsset *const asset = [AVAsset assetWithURL:url];
    AVAssetTrack *const videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] firstObject];
    NSError *error = nil;
    AVAssetReader *const assetReader = [AVAssetReader assetReaderWithAsset:asset error:&error];
    XCTAssertNil(error);
    AVAssetWriter *const assetWriter = [AVAssetWriter assetWriterWithURL:outputUrl fileType:AVFileTypeMPEG4 error:&error];
    XCTAssertNil(error);

    NSMutableDictionary *const compressionProperties = [NSMutableDictionary new];
    compressionProperties[AVVideoAverageBitRateKey] = @(bitRate);

    if (profile) {
        compressionProperties[AVVideoProfileLevelKey] = profile;
    }

    AVAssetWriterInput *const input = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo
                                                                     outputSettings:@{
                                                                         AVVideoCodecKey: codec,
                                                                         AVVideoWidthKey: @(720),
                                                                         AVVideoHeightKey: @(1280),
                                                                         AVVideoCompressionPropertiesKey: compressionProperties,
                                                                     }];
    input.transform = videoTrack.preferredTransform;

    AVAssetReaderOutput *const output = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack
                                                                         outputSettings:@{
                                                                             (id)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA),
                                                                         }];

    [assetReader addOutput:output];
    [assetWriter addInput:input];

    XCTAssertNil(assetReader.error);
    XCTAssertNil(assetWriter.error);

    CFTimeInterval start = CACurrentMediaTime();

    [assetReader startReading];
    [assetWriter startWriting];

    [assetWriter startSessionAtSourceTime:kCMTimeZero];

    const dispatch_queue_t queue = dispatch_queue_create("transcode", DISPATCH_QUEUE_SERIAL);
    const dispatch_semaphore_t transcode = dispatch_semaphore_create(0);
    [input requestMediaDataWhenReadyOnQueue:queue usingBlock:^{
        while ([input isReadyForMoreMediaData]) {
            const CMSampleBufferRef sampleBuffer = [output copyNextSampleBuffer];

            XCTAssertNil(assetReader.error);
            XCTAssertNil(assetWriter.error);

            if (sampleBuffer) {
                [input appendSampleBuffer:sampleBuffer];
                CFRelease(sampleBuffer);
            } else {
                [input markAsFinished];
                dispatch_semaphore_signal(transcode);
            }
        }
    }];

    dispatch_semaphore_wait(transcode, DISPATCH_TIME_FOREVER);

    const dispatch_semaphore_t write = dispatch_semaphore_create(0);
    [assetWriter finishWritingWithCompletionHandler:^{
        dispatch_semaphore_signal(write);
    }];

    XCTAssertNil(assetWriter.error);

    dispatch_semaphore_wait(write, DISPATCH_TIME_FOREVER);