Retrieving movie codec under iOS?

Question

I am trying to find the codec used to compress a movie. I am sure if I need to somehow use CMFormatDescription and get a CMVideoCodecType key. I am stuck as to how to get pa

Answer 1

A Swift approach to retrieving the audio and video codec associated with a movie:

func codecForVideoAsset(asset: AVURLAsset, mediaType: CMMediaType) -> String? {
    let formatDescriptions = asset.tracks.flatMap { $0.formatDescriptions }
    let mediaSubtypes = formatDescriptions
        .filter { CMFormatDescriptionGetMediaType($0 as! CMFormatDescription) == mediaType }
        .map { CMFormatDescriptionGetMediaSubType($0 as! CMFormatDescription).toString() }
    return mediaSubtypes.first
}

You can then pass in the AVURLAsset of the movie and either kCMMediaType_Video or kCMMediaType_Audio to retrieve the video and audio codecs, respectively.

The toString() function converts the FourCharCode representation of the codec format into a human-readable string, and can be provided as an extension method on FourCharCode:

extension FourCharCode {
    func toString() -> String {
        let n = Int(self)
        var s: String = String (UnicodeScalar((n >> 24) & 255))
        s.append(UnicodeScalar((n >> 16) & 255))
        s.append(UnicodeScalar((n >> 8) & 255))
        s.append(UnicodeScalar(n & 255))
        return s.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
    }
}