Transcoding an Input Stream

Zixi Broadcaster offers live transcoding, enabling users to create multiple bitrate streams from a single input stream.

Supported Video and Audio formats include:

• Video Decoding – MPEG2, H.264/AVC , H.265/HEVC
• Video Encoding – MPEG2, H.264/AVC , H.265/HEVC
• Audio Decoding – AAC, MPEG-1 Audio Layer I / II / III, MPEG-2 Audio Layer I / II / III
• Audio Encoding – AAC only, AAC only; Pass through – any audio codec (MPEG1/2 / AAC / AC-3)

The transcoder comes with pre-set common video profiles:
1080i60 / 1080i59.94, 1080p30 / 1080p25, 720p60, 720p50 / 720p30, 576i60 / 576p25, 480i60 / 480p29.97

In order to transcode an input stream from the Inputs screen you must first configure the transcoding profiles in the Transcoder screen. For more information, see Transcoder section. 

To Transcode an Input Stream:

1. In the Zixi Broadcaster Inputs page, click the desired incoming stream that you want to transcode.
2. Click  button on the right end of the selected row and then Transcode. The Transcode <input stream name> window with the settings of the selected input stream is displayed.
   
3. Enter the unique Stream I.D., which will correspond to the new transcoded input that will be added.
4. Under Stream Parameters, select one of the following options in Video Profile:
   • Keep original stream – the stream will not be modified.
   • Remove stream – the output will not include the video channel (audio only).
   • Custom profile – select one of the custom profiles that have been configured in the transcoder.  
5. Under Stream Parameters, select one of the following options in Audio Profile:
   • Keep original stream – the stream will not be modified.
   • Remove stream – the output will not include the audio channel (video only).
   • Custom profile – select one of the custom profiles that have been configured in the transcoder.
6. If you  have installed a GPU hardware accelerator on your transcoder you can select the Use hardware acceleration checkbox to enable acceleration.  
7. If you want to ensure all PIDs (which is used to distinguish between packets containing different types of information) are passed on through the transcoder, select the Pass all PIDs checkbox. To learn more about PIDs, see Packet Identifiers (PID). 
8. In the Smoothing buffer field, enter the buffering time in milliseconds. The buffering helps smoothen the stream, however it will delay its transfer by the duration that is specified in this field. Default: 1500 ms.
9. Select the relevant additional parameters as described below.
10. Click OK. The transcoded input stream is created and appears in an embedded window labeled Transcoded sources under the original input stream from which it was created.

Parameters Table