Creating New Transcoding Profiles

Preset

Select one of the pre-configured presets or select Custom to create a new profile from scratch. Even if you select a preset configuration, you can still change its settings.

Default: Custom

Name

Enter a unique name for the profile.

Encoder

Select one of the following options:

• X264 – software-based encoder (available for H.264 only).
• NVIDIA – NVIDIA-based hardware encoder.

Encoding Profile

Select the relevant encoding profiles:

For H.265 video profiles with hardware acceleration:

• Main (default) – this profile supports 8 Bit Per Pixel encoding (BPP).
•  Main 10 – this profile supports 10 Bit Per Pixel encoding (BPP).
• Main SP - The Main Still Picture profile allows for a single still picture to be encoded with the same constraints as the Main profile. As a subset of the Main profile the Main Still Picture profile allows for a bit depth of 8-bits per sample.

For H.264 video profiles:  

• High - The primary profile for broadcast and disc storage applications, particularly for high-definition television applications.
• Main - This profile is used for standard-definition digital TV broadcasts that use the MPEG-4 format as defined in the DVB standard.
• Baseline - Primarily for low-cost applications that require additional data loss robustness, this profile is used in some video conferencing and mobile applications.

For MPEG2 video profiles:

• High – supports SNR and Spatial Scalability and Intra DC Precision of 8, 9, 10, and 11.
• Main - supports I and P and B Picture Coding Types and Intra DC Precision of 8, 9, 10.
• Simple – supports I and P Picture Coding Types and Intra DC Precision of 8, 9, 10.

Resolution

Enter the new resolution in pixels, if resizing the video.

Keep Source Aspect Ratio

Select this checkbox (default) to maintain the original aspect ratio.

Frames per Second

Select a new frame rate or select Original to use the original frame rate of the stream.

Default: Original

Note: When a new frame rate is specified, it is applied using "Smooth frame rate conversion".

Note: When the frame rate is converted, captions in the elementary stream are preserved.

Average Bitrate (kbps)

Specify the average bitrate for the profile.

Max Bitrate (kbps)

Specify the maximum bitrate for the profile. Available only if the Bitrate Mode is set to VBR.

Performance

Select the performance of the transcoding. Possible values range from Ultra Fast which provides the best quality while utilizing high CPU/GPU to Slower which has the lowest quality but uses much less CPU/GPU.

Default: Very Fast

Copy GOP from source

Select this checkbox if you want to maintain the source GOP length (not structure). Enabling this option will generate an I-frame in the transcoded stream with the exact timestamp as in the source stream.

The Copy GOP from source option is only available when selecting the Original option in the Frames per Second field.

If you want to change the source GOP length specify the new GOP length in the GOP [Frames] parameter.  

GOP [frames]

Specify the number of frames in a GOP (Group of Pictures). Default:60

GOP Settings

• 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

Specify the maximal number of consecutive B frames in the GOP. Default: 0

Frame Type

Specify the frame type – progressive or interlaced (MPEG2 only on SW transcoding).

Default: Progressive

Reference Frames

Specify the number of frames that can be referenced for each frame.

Default: 2

HRD buffer length (seconds)

Specify the length of the HRD buffer in MPEG-2.

CRF

The Constant Rate Factor (CRF) is the default quality (and rate control) setting for x264 and x265 encoders. You can set the values between 0 and 51, where lower values would result in better quality, at the expense of higher file sizes. Higher values mean more compression, but at some point you will notice the quality degradation.

MAX QP

The QP (Quantization) parameter controls how the compression rate. Ranging from 0 (No compression) and 51 (Max compression). Max QP - controls the maximum value the encoder can set for QP.  For example, a low number will result in a lower compression rate causing the video to look better, however requiring a higher bitrate. A higher max QP value may reduce the visual quality but results in a lower bitrate.

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.

Bit Depth

Conversion of the 10-bit HDR color encoding source to 8 BPP.

This feature is enabled for the following configurations:

• H.264 – Encoder: X264; Encoding Profile: High 10.
• H.265 – Encoder: Nvidia; Encoding Profile: Main 10.

If the source is 10-bit, select one of the following:

• As Source – to maintain a 10-bit color encoding.
• 8 BPP – to down convert the source to 8 bit per pixel. if the source is already 8bpp, it does nothing.

Name

Enter a unique name for the profile.

Bitrate

Specify the bitrate for the profile.

Sampling Rate

You can convert the audio sampling rate from 44.1kHz to 48kHz and vice versa. Select one of the following options:

• Copy from source – if you do not wish to make any changes.
• 44.1kHz – to convert a 48kHz audio stream to 44.1kHz.
• 48kHz – to convert a 44.1kHz audio stream to 48kHz.

Encoding Profile (for AAC)

• AAC-LC (default) - AAC Low Complexity. The simplest and most widely used and supported profile.
• HE-AACv1 - AAC High Efficiency 1. This profile uses spectral band replication (SBR) to enhance the compression efficiency in the frequency domain.
• HE-AACv2 - AAC High Efficiency 2. couples SBR with Parametric Stereo (PS) to enhance the compression efficiency of stereo signals. It is a standardized and improved version of the eAAC+ codec.