Setting up an assembly workflow job - MediaConvert
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Setting up an assembly workflow job

Follow these steps to set up a job that combines assembly workflow features such as input clipping, input stitching, graphic overlay, and sidecar captions sync. Doing these tasks in this order can make setup easier. In particular, we recommend that you specify your input clips last. This is because each input timeline counts frames from the entire input, not from each individual clip.


You can’t use input clipping for audio-only jobs. All job outputs must have video.

This procedure relies on the concept of input and output timelines. For more information, see How MediaConvert uses timelines to assemble jobs.

To set up an assembly workflow job (console)
  1. Specify your video input files.

    You can have up to 150 inputs in a job. MediaConvert stitches together the inputs in the order that you add them. If you want to use multiple clips from the same input file, and you want them in chronological order without other inputs in between them, specify the input file only once.

    For full instructions, see Step 1: Specify your input files.

  2. Set up your audio selectors.

    In each input, you create audio selectors to map your input audio to your outputs. For instructions, see Step 2: Create input selectors for video, audio, and captions.

    With sidecar audio files, MediaConvert synchronizes audio and video without regard to timecodes. MediaConvert lines up the start of the audio file with the start of the video file.

    Whether your audio is in a sidecar file or is embedded in the video, you can adjust its sync using the Offset setting in the input audio selector. Use a positive number for Offset to move the audio later in the input timeline; use a negative number to move it earlier.

  3. Synchronize any sidecar captions.

    How you set up your sidecar captions sync depends on the input captions format:

    • If your input captions format is timecode-based (for example, SCC or STL), the service synchronizes the timecode in the captions file with the input timeline.

    • If your input captions format is timestamp-based (for example, SRT, SMI, or TTML), the service synchronizes the captions with the video without regard to timecodes.

  4. Set up when you want any graphic overlays or motion graphic overlays to appear.

    How you specify the time that the overlay appears depends on what kind of overlay you specify:

    • For input still graphic overlays, specify the overlay in the input where you want the overlay to appear. Specify the start and end times with timecodes that match with that input's timeline.

    • For output still graphic overlays, specify when you want the overlay to appear based on the output timeline.

    • For motion graphic overlays, specify when you want the overlay to appear based on the inputs' timelines.

  5. Specify input clips.

    Unless you want MediaConvert to include the full duration of the input, specify input clips for each input. Specify the start and end times with timecodes that match with that input's timeline.

    Set up input clips as follows:

    1. On the Create job page, in the Job pane on the left, choose an input.

    2. In the Input clips section, choose Add input clip.

    3. Enter the starting and ending timecodes for the first clip that you want to include. Use the following 24-hour format with a frame number: HH:MM:SS:FF.

      Make sure that you provide timecodes that align with your input timeline. By default, MediaConvert bases input clipping on timecodes that are embedded in your input video. How you align your timecodes depends on whether your input video has embedded timecodes:

      • If your input doesn't have embedded timecodes, you must set Timecode source to Start at 0 or Specified start.

      • If your input does have embedded timecodes and you want MediaConvert to use them, for Timecode source, keep the default value, Embedded. Specify your clip start and end times accordingly.

        For example, if your input Timecode source is set to Embedded and your video has embedded timecodes that start at 01:00:00:00, define the start timecode for a clip thirty seconds in as 01:00:30:00, not 00:00:30:00. By default, the input timeline is the same as the timecodes embedded in the video. You can change what determines the input timeline by adjusting the input Timecode source setting.

      • Specify an input clip duration that is less than 12 hours long.

      For more information, see Adjusting the input timeline with the input timecode source.

    4. Specify any additional clips. Multiple clips must be in chronological order and can't overlap; each Start timecode must come after the previous clip's End timecode.

      If you specify more than one input clip, they all appear in the output, one after the other, in the order that you specify them.