public static CodecType getVideoCodecType(byte tagByte) {
		switch(tagByte & 0x0F) {
		case 1: return JPEG;
		case 2: return H263;
		case 3: return SCREEN;
		case 4: return ON2VP6;
		case 5: return ON2VP6_ALPHA;
		case 6: return SCREEN_V2;
		case 7: return AVC;

		case 0: // 不明
		default:
			throw new RuntimeException("判定不能なコーデック");
		}
	}