December 12, 2016

Specifying decoder threads in Live Transcoder

Nimble Streamer Live Transcoder allows performing various transformations over incoming video and audio streams.

Any incoming stream needs to be decoded before any further transformation unless you use a pass-through mode. The decoding may be either hardware-based (such as NVidia GPU decoding supported by Live Transcoder or Intel QuickSync) or software-based.

Software decoding may be optimized in order to use processor resources optimally. This is why the Transcoder allows using multiple threads for video decoding.

By default the decoding is performed using one thread for one stream on one CPU core. If the decoding doesn't consume entire core, more threads are added into that core.

However, in some cases one core in not enough to decode one stream. If you look at Nimble logs you will see messages like
Failed to decode video in appropriate rate
This means you need to run one decoding thread on several cores - this is where multiple threads are used.

Notice that before adding new threads, make sure your CPU is not 100% loaded before adjusting threads number.

Let's see how you can set it up. In the transcoding scenario you need to point to video decoder blue rectangle (with a film on it) and then click on appeared gear button.

You'll see decoder settings dialog. In the Decoder drop-down list it will show "Default" option. This is a software decoder used by Nimble Transcoder by default.

Use Threads edit box to specify the number of sessions threads used for decoding in this this particular incoming stream. Now click OK and then save transcoding scenario to apply it to the server.

You can specify this separately to any decoder in any scenario

Visit Live Transcoder webpage for more details about Live Transcoder and contact us if you have any question.

Related documentation


  1. How can we use the transcoder output as an input MPEGTS to be output to the players?

    1. Hi,
      Any transcoder output can be used in further scenarios, just like any other input stream. Can you please send your request to with an example of stream so we could advise accordingly?


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