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Image extraction and thumbnails generation are a phase of encoding. Learn how the Encoding Service extracts frames from the video stream

Image Extraction Phase

This article discusses the image extraction and thumbnails generation, which are a part of encoding. You can find an overview of the entire encoding process in the Job Processing article.

Encoding_ServiceImages_StorageMessage_Publisheropt[If Required]Extract ImagesExtracted ImagesImagesExtractedopt[If Required]Extract Thumbnails & add as a stream
Figure 1. Interactions between the Encoding Service and the other systems during the Image Extraction Phase

Image Extraction

Encoding Service can extract frames from the video stream at specified time indexes and store them as JPEG images in a specified location. External systems (like Content Management) can use the generated images.

The section ImageExtraction of the job description is used to provide the necessary settings.

{
    "ImageExtraction": {
        "Quality": 85,
        "Intervals": [15, 25, 82],
        "Pattern": "preview_%.jpg",
        "Location": {
            ...
        }
    }
}

The example above signalizes to take 3 snapshots from the video, at the time indexes of 15, 25, and 82 percentages of the video length. The snapshots are stored as JPEG files with a quality of 85 as files named preview_1.jpg, preview_2.jpg and preview_3.jpg, respectively, in the specified Location. The format for Location is the same as for input/output storage.

Thumbnails

Encoding Service can generate thumbnails (used as preview images) at regular intervals and include them as a part of the DASH representation in accordance with the DASH IF IOP 4.3, section 6.2.6 "Tiles of thumbnail images". Any player supporting this DASH standard can display the thumbnails for any time index.