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dec

The dec command is used to manage A/V decoder settings. The dec start and dec stop commands can be used to start and stop decoding video. ID can be all or id1[,id2,id3,id4] with values from 0 to 3You can specify a comma-separated list of IDs for the operation, as shown in the examples that follow.

Synopsis

dec ID start
dec ID stop
dec ID set parameter=value [parameter=value]
dec ID get [config/stats/all] [video/buffer/metadata/audio/clockrecovery/all]
dec ID capture [filename=value] [resolution=WxH]
dec ID clear

Actions

ActionDescription

start

Starts decoding the video input.

stop

Stops decoding the video input.

set

Configures A/V decoder settings.

A series of one or more parameter=value pairs can be specified at once. See Parameters below.

get

Displays information on the decoder. You can choose to display the configuration (config), stats, or all [config/stats/all], and optionally specify a section of interest [video/buffer/metadata/audio/clockrecovery/all]

Tip

To display a summary of all the decoders in a table format, you can use dec all get table:

# dec all get table

ID STREAM ALT-STREAM STATE   FORMAT BUFFERING OUTPUTS
----------------------------------------------------------------------------------------
0 1 (None) ACTIVE NATIVE AUTOMATIC SDI-1
1 (None) (None) STOPPED NATIVE AUTOMATIC SDI-2
2 (None) (None) STOPPED NATIVE AUTOMATIC SDI-3
3 (None) (None) STOPPED NATIVE AUTOMATIC SDI-4

clear

Clears the decoder’s statistics.

help

Displays usage information for the dec command.

Parameters

ParameterDefaultDescription/Values

streamId

n/aPositive stream index. See Configuring Decoder Outputs.

stillImage

freeze

The type of static image to display when the decoder is not receiving a video stream.

  • freeze: continues to display the last decoded video frame.
  • black: displays a black screen.
  • blue: displays a blue screen.
  • bars: displays a series of vertical color bars across the width of the display.
  • mute: disables the video output.
  • custom: displays the custom still image specified for stillFile

Note

When the still image is substituted on the display outputs, the video frame rate and resolution will be maintained.

When the video decoder receives a new video stream, it waits until it receives a new IDR frame and re-starts the display with that IDR frame.

stillFilen/aFilename of the custom still image. Default images are provided, and your system administrator may have imported additional Still Images for your decoder. See mkstill.

stillDelay

3The delay in seconds before the still image is displayed: 1...1000

format

auto

The output display format:

  • Auto: The decoder will select an output resolution that attempts to closely match the coded picture resolution, taking into account the capabilities of any displays connected to the HDMI interface.
  • Native: The output resolution will be exactly the same as the coded picture resolution. If the coded picture resolution is not compatible with the output interfaces, nothing will be displayed. See "Output Resolution" in Decoder Settings.

Video scaling is not supported.

frameRate

auto

The output frame rate for the displays. Auto, 23, 24, 25, 29, 30, 50, 59 or 60

  • If Auto is selected, the actual frame rate generated will be the next highest valid frame rate supported by the SDI interface, plus the one that gives the best decimation factor. For example, 30Hz could be chosen instead of 29.970 Hz.
  • Values set which are impossible to implement will be treated as Auto. Reasons for not supporting the selection can range from “Display does not support the frame rate” or “Frame rate is undefined for the detected input resolution”.
bufferingautomatic

The type of buffering to use. A jitter buffer temporarily stores arriving packets in order to remove the effects of jitter from the decoded stream.

  • automatic - Set buffering automatically for good quality and proper sync
  • fixed - Set buffering for fixed delay (use delay=X parameter)
  • multisync - Set buffering for fixed delay from the encode time
    (use multiSyncDelay=X parameter, requires SYSTEM TC and NTP)
delayn/aThe delay in ms when using stc syncmode with fixed buffering: 0...3000
multiSyncDelayn/aThe delay in ms from encoder TC when using multisync buffering: 0...10000
hardwareDelayAddn/aThe number of ms to add to the delay for processing the output in the hardware. -20...200  
dropCorruptedFramesno

Configures the decoder to drop corrupted frames before they reach the decoder. yes, no 

dynamicrangeautomatic

Configures the decoder to detect the inbound High Dynamic Range (HDR) transfer function signaling and forward that information within the decoded stream. 

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

Note

HLG and PQ override the settings in the stream.

outputsn/a

A list of physical SDI outputs the decoder core will feed: 1..4

  • none, all, default, quad2SI, or id1[,id2,id3,id4] 

Examples

# dec 3,2,0 start

Starts decoders 3, 2 and 0 (in the order specified)

# dec 0 get stats

Returns (all) decoder statistics for decoder 0:

Decoder ID : 0
Statistics
State : ACTIVE
Up Time : 2d11h42m30s
Buffering
Buffering Mode : AUTOMATIC
Buffering State : ACTIVE
Video Latency : 363ms
PCR Updates : 4 (Last One: 1d18h59m4s ago)
STC Updates : 13 (Last One: 1d11h14m44s ago)
Buffering Adjustments : 6 (Last One: 1d11h14m44s ago)
STC Lead Time Adjusts : 8 (Last One: 1d11h14m44s ago)
STC to PCR Lead Time : -201ms (STC is behind PCR by 201ms)
Packets Sent Late : 21 (Last One: 8h44m12s ago, Max Late=95443694ms, Max Burst=11)
Max Input Jitter : 100ms (last changed 1d18h58m57s ago)
Non-Video Late : 0ms (max=0ms occurred Never)
Video Decoder Latency : 42ms (max=57ms occurred 1d10h42m54s ago)
Video Decoder Jitter : 33ms (max=153ms occurred 8h44m4s ago)
Hardware Delay : 50ms
Video STC Lead Time : 168ms (Min=166ms, Max=199ms, Range=33ms)
Last Video Skip/Replay: 8h44m11s ago
Audio STC Lead Time : 446ms (Min=426ms, Max=463ms, Range=37ms)
Last Audio Skip : 1d18h59m11s ago
Video
Preprocessor State : ACTIVE
Stream Properties
Compression : H.265
Color : 4:2:0 8-bit
Profile : Main
Level : 5.1
Format : 1920x1080p59.94
Bit Rate : 10.18 Mbps
Framing : IP
GOP Interval : 60
Slices per Frame : 1
Dynamic Range Stream : SDR
Dynamic Range Output : SDR
Metadata Present : None
Format Changes : 1 (Last One: 2m29s ago)
Input Frame Rate : 59.94 [100.0%] (measured)
Video Decoder State : ACTIVE
Display Format : 1920x1080p59.94
Video Decoder Load : 24%
Still Image : FREEZE (INACTIVE) [Count=0, Max=0s, Last On=Never, Last Off=Never]
Decoder Counters
VCU Frm not Release : 3 (Last One: 0s ago)
VCU IN Discontinuity : 1 (Last One: 2m29s ago)
HW Counters
Displayed Output Frms : 8,750 [98.1162%] (Last One: 1s ago)
Skipped Output Frames : 8 [0.0897%] (Last One: 1m47s ago)
Replayed Output Frames : 160 [1.7941%] (Last One: 31s ago)
Audio
Audio Decoder State : ACTIVE
Number of Pairs : 1
Played Output Frames : 6,939 [99.0578%] (Last One: 0s ago)
Skipped Output Frames : 66 [0.9422%] (Last One: 1m48s ago)
TS Discontinuities : 1
AUDIO PAIR #1
Compression : AAC-ADTS
Bit Rate : 80.32 kbps
A/V Sync : -2ms (Video TS 2830607135, Audio TS 2830607316)
TS Discontinuities : 3
Decoder Errors : 0
Output Errors : 0
Sample Rate In : 48000 Hz
Sample Rate Out : 48000 Hz
Metadata
Metadata State : IDLE
Clock Recovery
Tracking Mode : ENABLE
Status : UNLOCKED (more then +-5PPM)
ReSync Count : 2
PCR Updates : 2 (Last One: 2m19s ago)
Current STC : 27,000,723Hz (26PPM from Nominal)
STC Avg (last 2 min) : 27,000,495Hz (Deviation 14.0PPM)

# dec 0 get stats video

Returns (video) decoder statistics for decoder 0:

Decoder ID              : 0
Statistics
State : ACTIVE
Up Time : 4m15s
Video
Preprocessor State : ACTIVE
Stream Properties
Compression : H.265
Color : 4:2:0 8-bit
Profile : Main
Level : 5.1
Format : 1920x1080p29.97
Bit Rate : 10.03 Mbps
Framing : IP
GOP Interval : 60
Slices per Frame : 1
Dynamic Range Stream: SDR
Dynamic Range Output: HLG
Metadata Present : None
Stream ID Changes : 1 (Last One: 4m14s ago)
Format Changes : 1 (Last One: 4m14s ago)
Input Frame Rate : 29.96 [100.0%] (measured)
Still Image : FREEZE (INACTIVE) [Count=0, Max=18857d13h38m27s, Last On=Never, Last Off=4m10s ago]
Video Decoder State : ACTIVE
Display Format : 1920x1080p29.97
Video Decoder Load : 12%
Decoder Counters
VCU Frm not Release : 2 (Last One: 8s ago)
VCU IN Discontinuity: 0
HW Counters
Displayed Output Frms: 7,473 [92.9131%] (Last One: 0s ago)
Skipped Output Frames: 178 [2.2131%] (Last One: 3m50s ago)
Replayed Output Frames: 392 [4.8738%] (Last One: 4m ago)
# dec 1 set stillimage=blue

Sets the static image to blue. You will receive the following confirmation:

Decoder configured successfully.


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