Difference between duration_ts and duration in ffprobe output? I am relatively a beginner in ffmpeg and video production and was trying to extract duration of a video using ffprobe, using the following command:

ffprobe -loglevel error -select_streams v -show_entries stream -of json filename.mp4
Output:
{
    "programs": [

    ],
    "streams": [
        {
            "index": 0,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
            "profile": "Baseline",
            "codec_type": "video",
            "codec_time_base": "250/15007",
            "codec_tag_string": "avc1",
            "codec_tag": "0x31637661",
            "width": 640,
            "height": 352,
            "coded_width": 640,
            "coded_height": 352,
            "has_b_frames": 0,
            "pix_fmt": "yuv420p",
            "level": 30,
            "chroma_location": "left",
            "refs": 1,
            "is_avc": "true",
            "nal_length_size": "4",
            "r_frame_rate": "15007/500",
            "avg_frame_rate": "15007/500",
            "time_base": "1/30014",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 479000,
            "duration": "15.959219",
            "bit_rate": "1826913",
            "bits_per_raw_sample": "8",
            "nb_frames": "479",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0
            },
            "tags": {
                "rotate": "90",
                "language": "und"
            },
            "side_data_list": [
                {
                    "side_data_type": "Display Matrix",
                    "displaymatrix": "\n00000000:            0       65536           0\n00000001:       -65536           0           0\n00000002:            0           0  1073741824\n",
                    "rotation": -90
                }
            ]
        }
    ]
}


I have been trying to understand what is the difference between 

duration_ts and duration

Can someone just point me in the right direction to understand what each of them means?
I understand that the duration stands for run time of video but don't know what duration_ts here refers to.
duration is in seconds, e.g. 15.9
duration_ts is in the media's time_base, e.g. 1/30014 * 479000 = 15.959219