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    Live API: Creating a Frame-Accurate Clip

    This tutorial walks you though using the Live API to create a live job and then creating a frame-accurate clip from it.

    Overview

    This tutorial explains at the API level how to create a live streaming job in Brightcove live and then create a frame-accurate clip from it.

    Note that frame-accurate clipping requires that your encoder be sending SMPTE timecodes.

    This tutorial will use curl to make the API requests, but you can easily make them in Insomnia, Postman or other REST clients instead.

    Create a live job

    First, we will create a live job. You will need an API-KEY for the Live API. If you do not, and are interested in obtaining access, please contact your account manager.

    1. We assume you already have a brightcove acount and they you have your API-KEY, let's call it bcov-live-api-key
    2. Copy and paste the following curl command into a text editor:

        curl -X POST \
          https://api.bcovlive.io/v1/jobs \
          -H 'Content-Type: application/json' \
          -H 'x-api-key: ' \
          -d '{
            "live_stream": true,
            "region": "",
            "outputs": [{
              "label": "hls360p",
              "live_stream": true,
              "height": 360,
              "video_bitrate": 365,
              "segment_seconds": 6,
              "keyframe_interval": 60
            },
            {
              "label": "hls432p",
              "live_stream": true,
              "height": 432,
              "video_bitrate": 730,
              "segment_seconds": 6,
              "keyframe_interval": 60
            },
            {
              "label": "hls540p",
              "live_stream": true,
              "height": 540,
              "video_bitrate": 2000,
              "segment_seconds": 6,
              "keyframe_interval": 60
            },
            {
              "label": "hls720p3M",
              "live_stream": true,
              "height": 540,
              "video_bitrate": 2000,
              "segment_seconds": 6,
              "keyframe_interval": 60
            },
            {
              "label": "hls720p4.5M",
              "live_stream": true,
              "height": 540,
              "video_bitrate": 4500,
              "segment_seconds": 6,
              "keyframe_interval": 60
            }]
          }'
        
    3. Replace:

      • with the closest available region to your encoder, see closest available regions to your encoder. For instance: us-west-2
      • with your Brightcove live API key. For example: abcdfeg-this-is-a-fake-api-key-FgJajjasd12hJHsZ
    4. After making those changes, copy and paste the code into Terminal or whatever command-line app you use and run it.
    5. The response should be something like this:

        {
            "id": "3b6871bf2f344acaa6b397d09b476018",
            "outputs": [... removed for simplicity ...],
            "stream_url": "rtmp://ep1-usw2.bcovlive.io:1935/3b6871bf2f344acaa6b397d09b476018",
            "stream_name": "alive",
            "static": false,
            "encryption": {},
            "playback_url": "https://bcovlive-a.akamaihd.net/3b6871bf2f344acaa6b397d09b476018/us-west-2/NA/playlist.m3u8",
            "playback_url_dvr": "https://bcovlive-a.akamaihd.net/3b6871bf2f344acaa6b397d09b476018/us-west-2/NA/playlist_dvr.m3u8"
        }

    This jobs will create 5 renditions based on Apple recommendations.

    Configure your encoder

    The steps shown here will assume an Elemental live box encoder, which was used in testing the steps for this tutorial. If you have a different encoder, the settings should be similar.

    The most important settings for this case are:

    • Configure timecode source as "system clock"
    • Set "OnFi timecode frequency" to 1
    • Check "time code insertion" inside video
    • Strongly recommended: Framerate = follow source

    This is the config we used for this experiment:

    elemental-live-job-config
    Elemental live config

    Test playback

    You can use this VideoJS HLS demo page to test playback, just paste the value playback_url returned in the creation job response:

    videojs-hls-playback
    VideoJS HLS playback demo page

    Create a frame-accurate clip

    In this tutorial, we will assume that you are sending the clip to your Video Cloud library. If you are sending the clip to an S3 bucket or some other location, the process is the same - there are just some minor differences in the request body for the API requests.

    Credentials

    If you have not created credentials for Video Cloud in your Live account, you can follow the steps here to do so. This is a one-time operation.

    If you do not yet have client credentials for Dynamic Ingest of videos to Video Cloud, you will need to create them. See Managing API Authentication Credentials for instructions on how to do this in Studio.

    1. Copy the curl command below into a text editor:
      curl -X POST \ https://api.bcovlive.io/v1/credentials \ -H 'Content-Type: application/json' \ -H 'x-api-key: ' \ -d '{ "credential_default_for_type": true, "credential_label": "Video_Cloud_Uploads", "credential_private": "", "credential_public": "", "credential_type": "videocloud" }' 
    2. Replace:

      • with your Live API key
      • with your client secret
      • with your client id
    3. Copy and paste the edited command into Terminal or your command line app, and run it.
    4. The response should look similar to this:
        {
          "credential_id": "1e0180330b724dfbbcaf6b28b6c5d517",
          "user_id": "c2691d4d039040be96c190a949d754a7",
          "credential_label": "Video_Cloud_Uploads"
        }

    Create the clip

    Once you have your Video Cloud credentials, you are ready to create a clip.

    1. Copy the curl request below and paste it into a text editor:
        curl -X POST \
          https://api.bcovlive.io/v1/vods \
          -H 'Content-Type: application/json' \
          -H 'x-api-key: ' \
          -d '{
            "live_job_id":"",
            "outputs":[{
                "label": "Trim by SMPTE TC 17:33:11:12 to 17:34:00:00",
              "stream_start_timecode": "",
              "stream_end_timecode": "",
                "videocloud":{"ingest":{"capture-images":true},"video":{"name":"test-frame-accurate-clip"}},
                "credentials": ""
            }]
        }'
    2. Replace:

      • with your Brightcove live API key. For instance: abcdfeg-this-is-a-fake-api-key-FgJajjasd12hJHsZ
      • with the job id in the response to your request to create the live job. In our example this value would be 3b6871bf2f344acaa6b397d09b476018 - yours will be different.
      • and should be values that make sense (are present) in your live stream. In our example we have used: 17:33:11:12 and 17:34:00:00
      • with the label for your Video Cloud credentials. If you did not already have them and created them using the steps above, this would be Video_Cloud_Uploads
    3. Copy and paste the edited code into Terminal or your command line app, and run it.
    4. The response should look similar to this:
        {
            "vod_jobs": [
                {
                    "jvod_id": "0b14a4ba326d4dd08f15053ca2a403b7",
                    "label": "Trim by SMPTE Timecodes"
                }
            ],
            "live_job_id": "3b6871bf2f344acaa6b397d09b476018"
        }

    We tested the accuracy of the experiment we downloaded the clip and used Adobe premiere to checked the 1st and last frame, since the timecode is overlayed a simple visual check is enough to confirm the accuracy at input and output points:

    clip-accuracy-in
    Visual clip accuracy test - in
    clip-accuracy-out
    Visual clip accuracy test - out

     


    Page last updated on 28 Sep 2020