Вам необходимо установить параметры видеокодека:
NSDictionary *videoCleanApertureSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:320], AVVideoCleanApertureWidthKey,
[NSNumber numberWithInt:480], AVVideoCleanApertureHeightKey,
[NSNumber numberWithInt:10], AVVideoCleanApertureHorizontalOffsetKey,
[NSNumber numberWithInt:10], AVVideoCleanApertureVerticalOffsetKey,
nil];
NSDictionary *videoAspectRatioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:3], AVVideoPixelAspectRatioHorizontalSpacingKey,
[NSNumber numberWithInt:3],AVVideoPixelAspectRatioVerticalSpacingKey,
nil];
NSDictionary *codecSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:960000], AVVideoAverageBitRateKey,
[NSNumber numberWithInt:1],AVVideoMaxKeyFrameIntervalKey,
videoCleanApertureSettings, AVVideoCleanApertureKey,
//videoAspectRatioSettings, AVVideoPixelAspectRatioKey,
//AVVideoProfileLevelH264Main30, AVVideoProfileLevelKey,
nil];
NSString *targetDevice = [[UIDevice currentDevice] model];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
codecSettings,AVVideoCompressionPropertiesKey,
[NSNumber numberWithInt:320], AVVideoWidthKey,
[NSNumber numberWithInt:480], AVVideoHeightKey,
nil];