Adding Transcoding Profiles

Owned by Eli Pielet (Writec) (Unlicensed)
Last updated: 07 Oct 2024 by Alon Men
4 min read

You can add your own custom profiles at any time. You can also Clone an existing profile to create a new profile with a similar configuration.

To add a Transcoding Profile:

  1. In the main navigation, click Transformations > Transcoding Profiles.
  2. Click + Add. 
    The Create New Transcoding Profile screen is displayed:
  3. In the Name field, enter a name for the transcoding profile.
  4. In the Video section, select one of the following:
    • Transcode (default) – transcodes the video stream according to the settings of the transcoding profile.
    • Use Original – does not transcodes the video stream. This setting is used when you want to transcode the audio only.
    • Remove – removes the video track completely.
  5. If you selected Transcode, then continue with the following procedure. If you selected Use Original or Remove then proceed to the Audio configuration in step 14.
  6. Under Codec, select the radio button for the desired codec. Options are H.264 (AVC) or H.265 (HEVC).
  7. In the Encoding Profile field, select from the drop-down menu the desired encoding profile. For H.264 the options are: Main, Baseline or High. For H.265 the options are: Main or Main 10.
  8. In the Resolution section, do one of the following:
    • Select the Use Source Resolution checkbox to maintain the Source resolution, OR
    • Resize the video by entering the desired width and height in pixels.

  9. If you resized the video and you would like to maintain the original aspect ratio then select the Maintain Source Aspect Ratio checkbox.

    When this option is selected the unused space is filled in with black bars.

  10. In the FPS (frames per second) field, select one of the following options from the drop-down list:
    • Select Original to use the original frame rate of the stream, OR

    • Select a new frame rate from the list of frame rates.

      If you select an FPS that is different from the frame rate of the source video, "smooth frame rate conversion" is applied.

      For Zixi Broadcasters v13 and up, the captions in the elementary stream are preserved when the framerate is converted.

  11. If you would like to enable Variable Bitrate, select the VBR field and in the Video Bitrate section, enter the Average and Max video bitrate that the transcoder will output for this profile. 

  12. In the Performance field, select the performance of the transcoding with options ranging from 0 (Ultra Fast) to 8 (Very Slow). (Default value: 4 (Fast))

    The higher the performance quality selected the greater the CPU usage. Selection of Best Quality in a system that doesn't have sufficient available CPU will generate errors.

  13. If you would like to adjust the advanced video settings, click on Advanced Video.
    The Advanced Video settings are displayed.
  14. You can adjust the following settings:
    • GOP – specify the number of frames in a GOP (Group of Pictures) or select the Source checkbox to use the GOP setting of the Source. Default value: 30.
      • Closed – for a GOP in which the previous pictures do not need data from the subsequent GOP for bidirectional coding, select the Closed checkbox (default).
      • Fixed – to always use the specified number of frames in the GOP (as opposed to allowing the encoder to override), select the Fixed checkbox (default).

    • B Frames – specifies the maximal number of consecutive B frames in the GOP.

      If you are using a player that doesn't support B Frames then you must set the B Frame value as 0.

    • Interlaced – select the checkbox if you would like to create interlaced video.

      Interlaced is supported for MPEG2 on SW transcoding (not H.264).

    • Reference Frames – specify the number of frames that can be referenced for each frame (default 2).
    • HRD Buffer – specify the length of the HRD buffer in MPEG-2 (default 2).
    • Chroma Subsampling – converts the source chroma sub sampling (method for "compression" of raw images) to 4:4:4/ 4:2:2 / 4:2:0.
      • As Source – maintains the same chroma subsampling as in the source.
      • 4:4:4 is applicable for Nvidia HEVC codec or x264 high profile
      • 4:2:2 is not supported on Nvidia GPU
      • 4:2:0 is supported on Nvidia and x264.
  15. In the Audio section, select one of the following options:
    • Transcode – select this option to perform transcoding on the audio.
    • Use original – select this option to use the original audio settings. This setting is used when you want to transcode the video only.
    • Remove – removes the audio track completely.
  16. When Transcode is selected, the following audio settings can be specified:
    1. In the Audio Profile field, select the profile to be used. Options are: AAC Low Complexity (default), AAC High Efficiency, AAC High Efficiency v2 (for use with Broadcasters v13 and up).
    2. In the Audio Bitrate field, select from the drop-down list the audio bitrate in Kbps for this profile. (Default value: 80)

    3. In the Audio Sampling Rate field, select Original in the drop-down to apply the Original sampling rate OR select the desired resampling rate (1kHz or 48kHz).

    4. In the Audio Gain field, specify the gain value which increases or decreases the volume of an audio PID encoded using this profile:

      1. values between 0-1 means to decrease volume

      2. values > 1 means to increase volume

      3. 0 - (if allowed in that screen) means mute

      4. 1 -no change

        Resampling is supported for Zixi Broadcasters v13 and up.

  17. Click Save. 
    The transcoding profile is added to the list of profiles available in the Transcoding Profiles screen.