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iCap Alta TS Technical Specifications

Updated

This document provides the technical specifications for the iCap Alta TS.

Additional Documentation

iCap Alta TS Usage Recommendations

Specifications

Format & Protocol Specifications
Single or Multi-purpose streams Only single supported
IP video production formats
  • MPEG Transport Stream
  • SRT 
  • Zixi/RIST (through AWS Media Connect)​
Caption Input Formats
  • Lexi
  • iCap connection from Ai-Media or 3rd parties
  • Legacy connections to “telnet” style teleprompters and other devices
Video Formats
  • MPEG-2
  • H.264
  • AVC video (SEI data)
  • HEVC
Audio formats

Audio in codecs including:

  • MPEG-1, SMPTE 302M
  • Dolby AC-3 + Enhanced AC-3
  • AAC
  • Supports one audio language (or iso-track) per PID, with the audio in mono, stereo, or 5.1 Accepte.
Caption Output Formats
  • ATSC embedded CEA 608/708
  • SMPTE RDD-11 CEA-708
  • DVB Teletext
  • DVB Subtitles/Bitmap
Video transport protocols
  • RTP/UDP unicast
  • UDP multicast
  • MPEG-TS over SRT. 

RTMP is not supported.  
Caption bridging Allows for an additional input of captioning data by transferring data from a source stream into the primary stream.
Reference audio for iCap captioners Supports up to 6 audio tracks, each with separate language or audio service
Reference video for iCap captioners Supports 1 sent reference video
SCTE-104/35 Insertion and Passthrough Insertion: Supported by either sending SCTE-104 commands to Alta via a network (TCP/IP) or sending vGPI or API triggers based on SCTE pre-sets. If no SCTE-35 PID is defined in the channel settings, Alta defaults to inserting SCTE-35 messages in PID 498.
Passthrough: Pre-existing upstream SCTE-35 triggers can also be sent upstream to Alta, which will pass it through.
Logging: SCTE-104 commands received by Alta via TCP/IP or upstream will be reported in the channel logs. With Alta TS, SCTE-35 PID's are reported in the SCTE-35 Logs within the Alta channel settings. Whether sent upstream to Alta or if Alta inserts SCTE messages into a new PID.
Blocking/Unblocking Lexi with SCTE-104/35 Triggers

Supported by either sending SCTE-104 commands to Alta via a network (TCP/IP), or via sending SCTE-35 messages upstream to Alta.


Splice_start_immidiate triggers block Lexi (shutdown or pause) and Splice_end_immidiate triggers unblock (turn on or resume) Lexi. To turn Lexi on or off via either SCTE trigger type, set the Lexi Block Mode to Shutdown. To resume/pause Lexi via either SCTE trigger type, set the Lexi Block Mode Pause.
Audio Channel Mixing Supported in Alta TS via the Audio PID setting, on the iCap Settings page within Alta channel settings.
Deployment Specifications
Deployment Methods
  • VM / OVA file
  • AMI via AWS
  • Google Compute Engine Image via Google Cloud
  • Physical HP Proliant server
  • Physical proprietary NAP server

More info in iCap Alta TS Usage Recommendations.
Distribution format
  • OVA file for VM
  • AMI for AWS
  • Google Compute Engine Image for Google Cloud
  • pre-installed on Proliant and NAP servers
Compatible VM Controllers
  • VirtualBox
  • VMWare/VSphere/ESXi
Server & Networking Specifications
Security Alta uses a server-based authentication, connection, and encryption model with all instances safely behind existing firewalls. iCap also keeps detailed history logs of all authorized connections so you have full visibility of your system at all times.
Operating System Debian
Platform Linux
Transmission Specifications
In-to-out Video Latency

Latency is typically equivalent to your GOP size plus 1 to 2 seconds. This could vary depending on other factors, such as the “output buffer size” value in Alta: the higher the value, the longer the potential delay.

If using low latency mode, this may be reduced since there is no multiplexing of video GOP with the captions in this mode.

SRT may introduce an additional delay due to extra buffering since it is often used with unreliable networks. 

Note: Use Low-Latency mode only if you are not using ATSC User Data as the caption output format.
Audio to Caption Output Latency

Typical latency is 5 to 7 seconds, or 7 to 10 seconds if using LEXI Translate.

Using with CC Stream Out Only mode may also add 2-3 seconds of additional delay.
Note: Use CCMatch to eliminate this video latency. CCMatch delays the video by the same number of seconds the latency is observed. 
Newfor Stream Output

Supported when Alta channel is configured with DVB Teletext as the caption output format, but not currently DVB Subs/Bitmap or DVB TTML (support upcoming soon).

Currently one newfor stream can be output per Alta channel.

Note: Currently, when Newfor is sent to an Alta channel, and it is output to the iCap PC client, the PC Client will not show caption feedback. Additionally, the iCap/Lexi archive will currently not contain any captions in this case. This support is also coming soon.
SSM (source specific multicast) Input Filtering Support

To specify a specific stream source address, use this format in the Multicast Interface field:

ssm_ip@multicast_ip:port

where ssm_ip is the source-secific multicast IP address, and multicast_ip and port are the IP address and port of your multicast interface.
Sender Multicast Interface Override Support

Use this format in the Output field to specify an output address:

multicast_ip:port@interface_ip

where multicast_ip and port are the IP address and port of your multicast interface and ssm_ip is the source-secific multicast IP address.

This involves support for setting the multicast interface to NIC 1, with addressing the input Multicast Interface field as per <multicast_ip>:<port> and then overriding the interface on the Output field, such as <multicast_ip>:<port>@<ip_of_NIC2>.
Maximum decode delay for input stream Decode delay of the input TS must not exceed 1 second or buffering issues may occur.

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