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Video Encoder Settings

The following table lists the Video Encoder controls and settings: *

Input

Video Encoder SettingDefaultDescription/Values
InputBNC-1Select the Video Input port for the encoder:



  • BNC-1 or 2SI/SQD
  • BNC-2
  • BNC-3
  • BNC-4

Important

Only HD-BNC1 or 2SI/SQD can support 6/12G-SDI.

FIR FilterDisabled

(Finite Impulse Response filter) Check this checkbox to enable Input Image Filtering for the input interface. This parameter filters the video input and removes noise in order to optimize the compression of the image and to enhance the overall quality of the coded video stream.

Tip

Input Image filtering is useful with sources that are monochrome, noisy and difficult to encode because the content is detailed. Enabling this parameter filters the image in order to reduce the amount of noise, resulting in better quality video after the encoding since less noise is being compressed into the stream.

Note

FIR filter refers to a type of digital filter with a finite impact on the data being processed from a temporal or spatial perspective. FIR filters do not employ recursive or other feedback mechanisms.

The other major type of digital filter is the IIR (Infinite Impulse Response) filter. IIR filters have lingering impacts on the data being processed and employ feedback or recursive processing methods. 

Square DivisionDisabled

Check this checkbox to enable SQD (square division) encoding for UHD inputs. 

Note

This setting only appears when the encoder Personality is set to SQD. You can configure the Personality either from the Web Interface on the Status page (see Managing System Status Information) or via the personality CLI command (see personality).

Input Formatn/a

This is the input signal auto-detected from the video source. It includes the number of pixels per line, whether the video is interlaced or progressively scanned (indicated by i or p), and the number of frames per second.

Note

If the signal cannot be detected (or is outside the supported range), the Input Format will be Unknown.

*Assumes encoder Personality is SDI unless otherwise indicated.

Encoder Settings

Video Encoder SettingDefaultDescription/Values
Codec AlgorithmHEVC

Select the codec algorithm for the encoder: (See AVC and HEVC Encoding)

  • AVC/H.264
  • HEVC/H.265
Encoding ProfileMain

Select the application profile class for the encoder: (See Product Overview "4K Broadcast Quality Video".)



(AVC/H.264 only)
  • Baseline
  • Main
  • High
  • High 10
  • High 4:2:2


(HEVC/H.265 only)
  • Main
  • Main 10
  • Main 4:2:2 10
Chroma Subsampling4:2:0 8-bit

Select the Chroma Subsampling for the encoder:

  • 4:2:0 8-bit
  • 4:2:0 10-bit (Encoding Profile must be High 10, High 4:2:2, Main 10 or Main 4:2:2 10)
  • 4:2:2 8-bit (Encoding Profile must be High 4:2:2 or Main 4:2:2 10)
  • 4:2:2 10-bit (Encoding Profile must be High 4:2:2 or Main 4:2:2 10)

Dynamic Range


Automatic

(10-bit Chroma Subsampling must be selected) Select to configure the encoder to detect the inbound High Dynamic Range (HDR) transfer function signaling and forward that information within the encoded stream.

  • Off (SDR/BT.709)
  • Automatic: the encoder detects HDR transfer function from the source
  • HDR-HLG: HDR content is based on the Hybrid Log Gamma (HLG, BT.2100) transfer function
  • HDR-PQ: HDR content is based on the Perceptual Quantizer (PQ, SMPTE ST 2084/BT.2100) transfer function

Rate ControlCBR

Select the Rate Control for the encoder:

  • CBR (Constant Bitrate): Strictly respects the specified bitrate, aiming for a constant or unvarying bandwidth level.
  • CVBR (Capped Variable Bitrate): Allows the bit rate to vary but maintains the generated bitrate between the Maximum Bitrate and the specified Bitrate.
Max BitrateAuto(Rate Control must be CVBR) Enter the maximum video bitrate for the encoder: 32 to 120,000 Kbps
Bitrate6000 kbpsEnter the video bitrate for the encoder: 32 to 120,000 kbps
Partial Image SkipDisabled

(Rate Control must be CBR) Select whether to allow the encoder to skip part of the image in order to respect the bitrate limit.

This parameter is used to create streams that are CBR-compliant according to the MPEG-2 TS specification. One aspect of this functionality is to have the video encoder control the total number of bits generated across a GOP sequence to avoid overflowing the coded picture buffer (CPBuf). One method of doing this is to limit the size of individual video NALs associated with a frame when the bit budget is being over-subscribed. In essence the video encoder will skip encoding part of the image in order to not oversubscribe the bit budget for the GOP sequence. 

Partial Image Skip is useful for ISR customers who have multiple streams being decoded by various decoders with limited network bandwidth resources. In order to ensure that all the streams stay within their bandwidth budgets, they use CBR implementations of video encoders to constrain their output streams to adhere to specified bandwidth limits.

Note

Intra-Refresh is not an option in these situations since they use multiple types of decoders and not all of them support decoding Intra-Refresh content.
ResolutionAutomatic

Select the stream output resolution (i.e., the number of lines per frame and pixels per line to be encoded):

  • Automatic: Encodes at the same resolution as the incoming video.
  • Manually select the coded picture resolution from the list of available options (includes down-scaled resolutions). The options depend on the Input Format detected.

Note

Manually selecting a coded picture resolution will increase the video encoder latency by one (1) frame period.

For supported video encoding resolutions, see Supported Video Encoding Input and Downscale Resolutions (in Technical Specifications).

ResizingScale

(Resolution cannot be set to Automatic and must be less than the Input Format) Select whether to scale or crop the input to the desired resolution:

  • Scale: Changes the resolution of the encoded image from what is input to what is specified in Resolution parameter without discarding any portion of the image.
  • Crop: Crops the input and encodes to a rectangle within the input image while discarding the rest of the input image. When Crop is enabled, the output resolution is the portion of the input that is encoded from the center. This may be done instead of down-scaling.

By default, input is scaled to the specified output resolution.

Frame RateAutomatic

Select the coded picture frame rate per second:

  • Automatic: Encodes at the same frame rate as the input
  • 60..1

Note

The frame rate cannot exceed the input frame rate.
FramingIP

Select the video compression mode for the encoded video:

  • I: I frames only (lowest delay; lowest quality)
  • IP: I and P frames only
  • IBP: I, B and P frames
  • IBBP: I, BB (two B frames in sequence) and P frames
  • IBBBP: I, BBB (three B frames in sequence) and P frames
  • IBBBBP: I, BBBB (four B frames in sequence) and P frames (highest delay; highest quality)

Note

B frames require a Main Profile decoder. B frames provide more quality as the encoding is more efficient; thus more details can be rendered in the same bandwidth/bitrate.

Tip

When B frames are used, the GOP may be rounded up to make the sequence end with a P frame.
Intra-RefreshDisabled

Check this checkbox to enable Intra-refresh video encoding support. Intra-refresh minimizes latency, smooths the video bitrate, and minimizes GOP pulsing artifacts.

Intra-refresh is a video encoding mode of operation in which no distinct IDR frame is sent in the video elementary stream. Instead, the macro-blocks that make up the IDR frame are sent gradually within a certain time so that the entire video reference frame is rebuilt (at the decoder) within the number of frames specified as follows:

  • For H.264/AVC the Intra Refresh Interval = Horizontal Encoded Resolution / 16
  • For H.265/HEVC the Intra Refresh Interval = Horizontal Encoded Resolution / 32

The result is rounded up to nearest integer if it is fractional. For example: If the video encoder is encoding an output resolution of 3840x2160p60 using H.264, then the expected refresh interval is:  3840 / 16 = 240 (frames) / (60 frames/sec) = 4 seconds for a full image refresh period.

Tip

Intra-refresh requires that decoders that do not support random access points be started before the encoder is started.  This can be accomplished by establishing a stream from the encoder to the decoder then stopping and starting the video encoder.

GOP Size120(Intra-Refresh must be disabled) Enter the Group of Pictures size for the encoded video. 1..1000

slices


1

Configures the encoder to use multiple slices per frame instead of the normal 1 slice per frame encoder configurationEncoding latency is improved since encoded slices can be transmitted on the network without having to wait for the whole frame to be encoded. 1..11

Note

Latency improvements are only seen on decoders that do not buffer entire video frames before decoding and can actually decode and output slices.

Multiple slices cannot be used in conjunction with Partial Image Skip or Framing containing B-frames (IBP, .... IBBBBP).

Closed CaptioningDisabled

(Optional) Check this checkbox to enable Closed Captioning on the output Stream.

TimeCode SourceNone

Timecodes are used to mark video frame wall clock times, for editing purposes or for multi-channel synchronization. This field either disables timecoding, or selects the source to “timecode” the encoded video frame. The following selections are available:

  • None: No time code will be inserted in the video stream (saves bandwidth if not required).
  • Video (SDI only): The timecode will be extracted from the Ancillary Vertical Interval (ATC_VITC) incoming SDI video signal. Please note that Digital (D-VITC) and Linear Timecode (LTC) are not supported.
  • System: If no timecode is included in the video feed, the encoded timecode is based on the encoder’s system clock. In this case, it is recommended to enable NTP (see Configuring Network Settings).

Counting Mode


SMPTE 12M-1

(TimeCode Source must be System) Selects the TimeCode Counting Mode: 

  • SMPTE 12M-1: Drops values 00 and 01 every minute, except every 10 mins.
  • UTC Conversion: Derives the generated timecode (in HH:MM:SS:FF format) from UTC (Coordinated Universal Time). Dropped timecode values occur as needed to avoid drift and not at predetermined points in the timecode count sequence.
Daily ResyncEnabled

(TimeCode Source must be System with SMPTE12M-1 Counting Mode selected) Check this checkbox to enable timecode daily resyncs.

Note

Daily Resync and Resync Hour available starting release 1.3.1.

Resync Hour00:00 (midnight)

(Daily Resync must be enabled/checked) Select the time for the resync to occur from the drop-down list (ranging from 00:00 to 23:00).

Aspect RatioAutomatic

Specifies the aspect ratio of the video source and signals it into the MPEG stream:

  • Automatic: Aspect ratio is derived from the incoming video source resolution.
  • Manually force aspect ratio to either: 1:2, 3:2, 4:3, 5:3, 5:4, 16:9, 16:10, or 17:9.

    Note

    When streaming interlaced HEVC streams to a software player that does not support interlaced HEVC (most software players), select 1:2 for the aspect ratio. Software players that do not handle interlaced HEVC video properly will display each received field as a complete frame of half the vertical resolution, which will then be displayed as a vertically squeezed image.

  • WSS/AFD: Aspect ratio is extracted from the incoming video source based on WSS (Wide Screen Signaling) or AFD (Active Format Description) if detected.

    Note

    WSS is only supported with analog PAL video; AFD is only supported with SD-SDI video.

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