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Is this an appropriate use of the transcoder? If not, alternative method?

My goal was to retrieve a preview thumbnail image of a live stream in progress. After some research, I found a method . After enabling the transcoder, I set the audio and video to ‘passthrough’, but that doesn’t work; an encoding (240p, 480p…) must be selected for the transcoder to yield a thumbnail. I chose the option that matches the broadcast. It works, I get the preview thumbnails, but my concern is the CPU overhead incurred as a result of the transcoder running. Is this approach recommended? If not, what other route can I take?

Although I have found other solutions, they were in outdated threads and, frankly, hackish.


In order to retrieve a frame from a live stream, it would need to be decoded by Wowza, which requires enabling the Transcoder. A passthru rendition does not trigger the transcoder, but specifying an output rendition would. The downside, unfortunately, is the load on your CPU. The alternative to getting a thumbnail frame without a transcoder are the ones you have found already, which essentially grabs a single-frame recording of the live stream. If you find that you are using a more than 60% of your CPU resources using transcoding, you may want to consider going through the alternative route instead.