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Inspecting Assets

When working with user generated content or media form third party services, you may not have details about the asset, like width, height, duration, or framerate.

The Shotstack API comes with a probe endpoint that can be called to retrieve metadata for any asset hosted online.

Calling the probe endpoint#

To call the probe endpoint you send a get request to the following URL, with the URL of the asset to be inspected.

GET https://api.shotstack.io/{{ENV}}/probe/{{ASSET_URL}}

The ASSET_URL is the file to inspect and must be URL encoded.

An example URL is:

https://api.shotstack.io/v1/probe/https%3A%2F%2Fgithub.com%2Fshotstack%2Ftest-media%2Fraw%2Fmain%2Fcaptioning%2Fscott-ko.mp4

Reading the probe response#

The URL above returns the following payload:

{
"success": true,
"message": "ok",
"response": {
"metadata": {
"streams": [
{
"index": 0,
"codec_name": "h264",
"codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
"profile": "Main",
"codec_type": "video",
"codec_time_base": "1001/48000",
"codec_tag_string": "avc1",
"codec_tag": "0x31637661",
"width": 1920,
"height": 1080,
"coded_width": 1920,
"coded_height": 1088,
"closed_captions": 0,
"has_b_frames": 1,
"pix_fmt": "yuv420p",
"level": 41,
"color_range": "tv",
"color_space": "bt709",
"color_transfer": "bt709",
"color_primaries": "bt709",
"chroma_location": "left",
"refs": 1,
"is_avc": "true",
"nal_length_size": "4",
"r_frame_rate": "24000/1001",
"avg_frame_rate": "24000/1001",
"time_base": "1/48000",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 1241240,
"duration": "25.859167",
"bit_rate": "10044458",
"bits_per_raw_sample": "8",
"nb_frames": "620",
"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": {
"language": "eng",
"handler_name": "VideoHandler"
}
},
{
"index": 1,
"codec_name": "aac",
"codec_long_name": "AAC (Advanced Audio Coding)",
"profile": "LC",
"codec_type": "audio",
"codec_time_base": "1/48000",
"codec_tag_string": "mp4a",
"codec_tag": "0x6134706d",
"sample_fmt": "fltp",
"sample_rate": "48000",
"channels": 2,
"channel_layout": "stereo",
"bits_per_sample": 0,
"r_frame_rate": "0/0",
"avg_frame_rate": "0/0",
"time_base": "1/48000",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 1242096,
"duration": "25.877000",
"bit_rate": "317375",
"max_bit_rate": "317375",
"nb_frames": "1215",
"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": {
"language": "eng",
"handler_name": "SoundHandler"
}
}
],
"chapters": [],
"format": {
"filename": "https://github.com/shotstack/test-media/raw/main/captioning/scott-ko.mp4",
"nb_streams": 2,
"nb_programs": 0,
"format_name": "mov,mp4,m4a,3gp,3g2,mj2",
"format_long_name": "QuickTime / MOV",
"start_time": "0.000000",
"duration": "25.920000",
"size": "33513207",
"bit_rate": "10343582",
"probe_score": 100,
"tags": {
"major_brand": "isom",
"minor_version": "512",
"compatible_brands": "isomiso2avc1mp41",
"encoder": "Hybrik 1.215.18"
}
}
}
}
}

The response includes a response.metadata object that includes streams and format metadata. The streams array contains information about the media files audio and video streams.

Note that the video stream is usually index 0 but not always. Your application will need to parse the response and check the codec_type to be sure.

The format object includes information about the file itself such as file size, filetype, duration and bitrate.

Info

Under the hood the probe endpoint uses FFprobe to read the metadata of a media file. The metadata value is the exact same output that FFprobe returns, converted to JSON.