Decoding

Decoding

Video decoding

The Receiver services are designed to decode video, audio and data from an incoming transport stream.
There are two video decoding methods, depending on the hardware purchased:

  • 4:2:0 / 4:2:2 HD and UHD decoding making use of the optional hardware accelerator card MKP/UPH/PCI/ACC/ENH.
  • 4:2:0 / 4:2:2 SD, HD and UHD decoding when making use of the optional Dektec SDI output card MKP/UPH/PCI/SDI/DTA.

Video formats and decoding standards with accelerator card

ResolutionFrame rateBit depthChromaCodec
1920 x 1080i25/29.97 fps8/10 bit4:2:0/4:2:2MPEG-2 H.264 H.265
1280 x 720p50/59.94 fps8/10 bit4:2:0/4:2:2MPEG-2 H.264 H.265
1920 x 1080p50/59.94 fps8/10 bit4:2:0/4:2:2MPEG-2 H.264 H.265
3840 x 2160p50/59.94 fps10 bit4:2:0/4:2:2H.265

Video formats and decoding standards without accelerator card

ResolutionFrame rateBit depthChromaCodec
720 x 480i29.97 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265
704 x 480i29.97 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265
720 x 576i25 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265
704 x 576i25 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265
1920 x 1080i (3)25/29.97 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265 JPEG-XS (2)
1280 x 720p50/59.94 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265 JPEG-XS (2)
1920 x 1080p50/59.94 fps8/10 bit4:2:0/4:2:2MPEG-2 (1) H.264 H.265 JPEG-XS (2)
3840 x 2160p50/59.94 fps10 bit4:2:0H.265

(1) MPEG-2 is 8-bit only.

(2) JPEG-XS is 10-bit only.

(3) Currently sub-resolutions are not supported without the accelerator card being present.

Delay Modes

Contribution decoding delay modes (latency)

The modes described here are used to configure decoding delay, or latency of the Contribution decoder. The delay modes effect the delay between the PCR/PTS relationship and delaying picture display (when compared to the system clock reference).

Delay modes:

  • Compatibility: This mode has the longest delay. This mode ensures compatibility between all encoding units, in all modes.

  • Standard: This is the default value. Standard mode allows using all current encoders, in all modes.

    Older encoders that have buffer models that are too aggressive may prevent you from being able to use Standard mode for all bit rates and/or all audio encoding schemes.

  • Low: This is the recommended setting for simple contribution links. You can also use this mode in any context where a low delay is required.

  • Super Low: This is the recommended setting for simple contribution links using ONLY encoders also in Super Low delay mode.

    • Tests were carried out using a MediaKind AVP 2000 fitted with a CE-HEVC card running in super low delay mode.
    • Only audio passthrough (either Dolby-E or LPCM) is supported in this mode.
    • For multi-video decodes in this mode, it is recommended that all video components are supplied within the same transport stream.

Setting delay mode

  1. From the Home page, select the RECEIVER item from the required feed then click .

  2. Open the Decoding tab in the Parameters window.

  3. Select a Delay mode.

Low delay mode has been designed and tested to ensure an optimized error free minimum end to end delay. If a problem occurs trying to decode a valid input transport stream, please try Standard and Compatibility delay modes before raising a support request.

Maximum decoding density

The maximum decoding density for an RX1 with accelerator card is as below:

ResolutionChromaMax video decodesMax audio decodes
(tested with Dolby Digital)
All HD resolutions4:2:0/4:2:2416
All HD resolutions4:2:0/4:2:2320
3840 x 2160p4:2:0/4:2:218

The maximum decoding density for an RX1 without accelerator card is as below:

ResolutionChromaMax video decodesMax audio decodes
(tested with Dolby Digital)
All SD resolutions4:2:0420
All SD resolutions4:2:218
All HD resolutions except for:
1920 x 1080i25 H.264
1920 x 1080i29.97 H.264
4:2:0420
1920 x 1080i25 H.2644:2:0320
1920 x 1080i29.97 H.2644:2:0312
All HD resolutions4:2:218
3840 x 2160p4:2:018

The maximum decoding density for 4:2:2 software decoding is defined as 1 receiver service with 8 audio decodes.

  • The RX1 is capable of decoding either 1 UHD service, or up to 4 independent HD full bit rate services.
  • If an RX1 is running a UHD service it cannot decode anything else at that time, even if the incoming video being decoded is an HD resolution.

JPEG-XS HD Decode Maximum Bitrates

The Receiver service supports the decode of JPEG-XS streams up to 1080p60.

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JPEG-XS is a “lite” compression standard, therefore input elementary streams will be of high bitrate.

The following maximum bitrates must be observed when decoding using JPEG-XS.

For a single Decode, the following maximum bitrates are available:

ResolutionES bitrate of encoded serviceTS bitrate at input
720p59.94 H264 10 bit 422650 Mbps668.0 Mbps
1080p59.94 HEVC 10 bit 422660 Mbps678.0Mbps
1080i29.97 HEVC 10bit 422720 Mbps739.0 Mbps

When not using the accelerator card for decoders sourced from the same multicast within the RX1 server, the following maximum bitrates are available:

ResolutionInput TSNo of decodersES bitrate of encoded serviceTS bitrate at input
720p59.94H264 10-bit 422JPEG-XS 10 bit 422,1 x video and 3 x audios4x HD Decoder services250 Mbps257.8 Mbps
1080i29.97 HEVC 10-bit 422JPEG-XS 10 bit 422, 1 x video and 3 x audios4x HD Decoder services250 Mbps258 Mbps
1080p59.94 HEVC 10-bit 422JPEG-XS 10 bit 422, 1 x video and 3 x audios4x HD Decoder services150 Mbps155 Mbps
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Use of separate multicasts for source input will reduce the bitrates shown.

When using the accelerator card for decoders sourced from the same multicast within the RX1 server, the following maximum bitrates and number of decodes are possible:

ResolutionInput TSNo of decodersES bitrate of Encoded ServiceTS bitrate at input
720p59.94H264 10-bit 422JPEG-XS 10 bit 422, 1 x video and 3 x audios4x HD Decoder services250 Mbps257.8 Mbps
1080i29.97 HEVC 10-bit 422JPEG-XS 10 bit 422, 1 x video and 3 x audios4x HD Decoder services250 Mbps258 Mbps
1080p59.94 HEVC 10-bit 422JPEG-XS 10 bit 422, 1 x video and 3 x audios3x HD Decoder services150 Mbps156 Mbps
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Use of separate multicasts for source input will reduce the bitrates shown.

Configuration of decoding

Refer to the Receiver component documentation on how to configure decoding.