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
| Resolution | Frame rate | Bit depth | Chroma | Codec |
|---|---|---|---|---|
| 1920 x 1080i | 25/29.97 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 H.264 H.265 |
| 1280 x 720p | 50/59.94 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 H.264 H.265 |
| 1920 x 1080p | 50/59.94 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 H.264 H.265 |
| 3840 x 2160p | 50/59.94 fps | 10 bit | 4:2:0/4:2:2 | H.265 |
Video formats and decoding standards without accelerator card
| Resolution | Frame rate | Bit depth | Chroma | Codec |
|---|---|---|---|---|
| 720 x 480i | 29.97 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 |
| 704 x 480i | 29.97 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 |
| 720 x 576i | 25 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 |
| 704 x 576i | 25 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 |
| 1920 x 1080i (3) | 25/29.97 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 JPEG-XS (2) |
| 1280 x 720p | 50/59.94 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 JPEG-XS (2) |
| 1920 x 1080p | 50/59.94 fps | 8/10 bit | 4:2:0/4:2:2 | MPEG-2 (1) H.264 H.265 JPEG-XS (2) |
| 3840 x 2160p | 50/59.94 fps | 10 bit | 4:2:0 | H.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
-
From the Home page, select the RECEIVER item from the required feed then click .
-
Open the Decoding tab in the Parameters window.
-
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:
| Resolution | Chroma | Max video decodes | Max audio decodes (tested with Dolby Digital) |
|---|---|---|---|
| All HD resolutions | 4:2:0/4:2:2 | 4 | 16 |
| All HD resolutions | 4:2:0/4:2:2 | 3 | 20 |
| 3840 x 2160p | 4:2:0/4:2:2 | 1 | 8 |
The maximum decoding density for an RX1 without accelerator card is as below:
| Resolution | Chroma | Max video decodes | Max audio decodes (tested with Dolby Digital) |
|---|---|---|---|
| All SD resolutions | 4:2:0 | 4 | 20 |
| All SD resolutions | 4:2:2 | 1 | 8 |
| All HD resolutions except for: 1920 x 1080i25 H.264 1920 x 1080i29.97 H.264 | 4:2:0 | 4 | 20 |
| 1920 x 1080i25 H.264 | 4:2:0 | 3 | 20 |
| 1920 x 1080i29.97 H.264 | 4:2:0 | 3 | 12 |
| All HD resolutions | 4:2:2 | 1 | 8 |
| 3840 x 2160p | 4:2:0 | 1 | 8 |
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.
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:
| Resolution | ES bitrate of encoded service | TS bitrate at input |
|---|---|---|
| 720p59.94 H264 10 bit 422 | 650 Mbps | 668.0 Mbps |
| 1080p59.94 HEVC 10 bit 422 | 660 Mbps | 678.0Mbps |
| 1080i29.97 HEVC 10bit 422 | 720 Mbps | 739.0 Mbps |
When not using the accelerator card for decoders sourced from the same multicast within the RX1 server, the following maximum bitrates are available:
| Resolution | Input TS | No of decoders | ES bitrate of encoded service | TS bitrate at input |
|---|---|---|---|---|
| 720p59.94H264 10-bit 422 | JPEG-XS 10 bit 422,1 x video and 3 x audios | 4x HD Decoder services | 250 Mbps | 257.8 Mbps |
| 1080i29.97 HEVC 10-bit 422 | JPEG-XS 10 bit 422, 1 x video and 3 x audios | 4x HD Decoder services | 250 Mbps | 258 Mbps |
| 1080p59.94 HEVC 10-bit 422 | JPEG-XS 10 bit 422, 1 x video and 3 x audios | 4x HD Decoder services | 150 Mbps | 155 Mbps |
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:
| Resolution | Input TS | No of decoders | ES bitrate of Encoded Service | TS bitrate at input |
|---|---|---|---|---|
| 720p59.94H264 10-bit 422 | JPEG-XS 10 bit 422, 1 x video and 3 x audios | 4x HD Decoder services | 250 Mbps | 257.8 Mbps |
| 1080i29.97 HEVC 10-bit 422 | JPEG-XS 10 bit 422, 1 x video and 3 x audios | 4x HD Decoder services | 250 Mbps | 258 Mbps |
| 1080p59.94 HEVC 10-bit 422 | JPEG-XS 10 bit 422, 1 x video and 3 x audios | 3x HD Decoder services | 150 Mbps | 156 Mbps |
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.