Hitless Failover

On all platform components, Zixi V12 features hitless failover for inputs, enabling undisrupted streaming when switching from one source to another. Zixi's new hitless failover feature is based on the SMPTE 2022-7 standard, which specifies “seamless” or hitless failover between binary-identical streams with synchronized RTP headers. Zixi's patent-pending hitless failover technology works by comparing the transport stream payload, without relying on sequences being synchronized. Zixi then applies a proprietary sequencing algorithm to identify missing parts and fill-in missing packets.

Content Analysis

Zixi Broadcaster V12 now includes analysis of video content in addition to existing transport and network analysis. The content analysis feature offers the following analysis of the stream's audio and video content:

• Audio levels – Detects audio volume level for every channel on AAC or MPEG audio. The analysis of the various audio tracks is available in the audio tree. The volume is presented in dBFS (Decibels relative to full scale).
• Audio silence detection (AAC/MPEG audio) – Detects silence (dBFS< -90) on AAC or MPEG audio with a duration of about 30s or longer. 
• Audio clipping detection - Detects clipped audio upon occurrenceon AAC or MPEG audio.
• Blank video detection - Detects blank frames of any color for a duration of about 60s or longer.
• Frozen video detection - Detects frozen video, i.e. no motion, for a duration of about 60s or longer.
• I-Frame Quantization Parameter – This indicator detects cases where the source encoder configuration is creating excessively lossy content. The analysis does not rely on the bitrate, but rather extracts the global quantization parameter, which is a parameter that indicates how much information was lost during encoding, from the elementary stream.

OTT Protocols

The following enhancements have been implemented in V12 Broadcaster for OTT delivery via RTMP, HLS, and DASH outputs:

• Fragmented MP4 mode in HLS – The same MP4 fragments in DASH are supported in HLS.
• HEVC support in HLS on Apple devices (in MP4 mode) – Previous versions included HEVC support, but not on Apple devices. The new version includes HEVC support on Apple devices as well.
• Multi-audio HLS in separate streams –Allows playing multiple audio tracks in HLS, where every audio track is played from a different file.
• HEVC and Opus support in RTMP– The HEVC video codec and Opus audio coded are now supported in RTMP, including the ability to generate them, terminate them and send them from a mobile device/app. This is a non-standard flavor of the RTMP protocol requested by some customers.
• HEVC support in DASH – The HEVC video codec is now supported in MPEG-DASH.
• SCTE-35 markers converted to MPEG-DASH manifest – SCTE markers from the source transport stream now propagate to tags in the manifest of MPEG-DASH streams.
• API for SCTE-35 injection into adaptive streams manifest – With the Zixi Broadcaster API, it is now possible to inject SCTE markers into the adaptive stream manifest in both HLS and MPEG-DASH. This function can be also used to insert additional metadata.
• Preserve close captions after transcoding (H.264 &HEVC only) – Closed captions are automatically preserved when transcoding, as long as the source and the destination streams are H.264 or HEVC.
• Option to keep aspect ratio in transcoder – It is now possible to maintain the aspect ratio when transcoding.

Simplified FEC (Forward Error Correction)

The FEC feature has been optimized and is now enabled by default. The system now dynamically adjusts the FEC Block Latency according to network conditions, such as Packet Loss Rate, RTT, Jitter, etc. However, the overhead bitrate will never exceed the configurable Max FEC Overheadpercentage setting, which is the percentage above the source bitrate (default value is 30%).  While FEC Block Latency is dynamically adjusted by default, in Zixi Feeder it is exposed as an Advanced Setting and can be configured according to the desired CPU utilization rate.

The FEC Block Latency (ms) parameter sets the number of milliseconds that Zixi protects with a single FEC block. The larger the block, the more CPU utilization is required. However, it is able to recover from longer packet drops using FEC only.

IFB Support

Interruptible Foldback (IFB), also known as Interruptible Feedback or switched talkback, is a monitoring and cueing system for one-way communication from the director or assistant director to on-air talent or a remote location. IFB support has been implemented in Zixi Broadcaster Pull and UDP outputs, allowing the decoder with a Zixi Receiver to send audio back to the encoder with a Zixi Feeder. This offers the ability to, for example, give audio feedback to the camera operator.

Automatic Crash Reports

If Zixi Broadcaster, Feeder, or Receiver crashes, Zixi support will automatically receive an email containing the call stack of the event. This simplifies the support process and will eliminate the need to connect remotely to the system or send out log reports. Although the report is anonymous and does not include any sensitive data (e.g. configuration data, etc.), this feature is optional and can be turned off through the Settings menu.

Security Enhancements

V12 features new security enhancements that will ensure more stable and secure video delivery:

• API request limit – To avoid DDoS attacks, API requests are limited to 128K.
• XML-based API deprecated – To harden security further, the XML-based API is no longer supported.
• HTTPS support - HTTPS support was added to the HTTP authentication.
• chacha20/poly1305 cipher support – This cipher is the default mode for mobile devices on Zixi's HTTP and DTLS servers, offering greater efficiency for mobile devices.
• Trusted root certificates - Updated trusted root certificates for DTLS/TLS on Linux.

Supported Operating System Changes

In V12, Zixi Broadcaster is no longer supported on CentOS 6.x; it must be run on 64-bit CentOS 7.x or an equivalent Linux distribution with glibc 2.14+.  The Zixi Feeder and Receiver components are still supported on CentOS 6.x with glibc 2.12+, but now only on 64-bit distributions.

Prior to V12 there was one Zixi Broadcaster application without the transcoder and one Broadcaster application with the transcoder included.  In V12, the Zixi Broadcaster application without the transcoder is no longer needed as the transcoder is now always bundled with Broadcaster and enabled via a license.

Push Input Replacement Conditions

In V12, Zixi Broadcaster replaces an active Push Input only if the destination (IP or port) of the new connection matches the existing one, and if the stream name, password, and source IP match. This means that when two Zixi Feeders push the same stream to a single Zixi Broadcaster from the same IP address at the source and land at two different IP addresses at the destination (Zixi Broadcaster), or different ports of the same Zixi Broadcaster, they will not disconnect each other.

Transcoder Hardware Acceleration Check

Zixi Broadcaster V12 features a button that checks for the necessary hardware components to support Intel hardware acceleration for transcoding. If the existing hardware matches the requirements, an Install button appears. Clicking it will install a kernel, which includes the Linux kernel with the Intel patches that enable hardware acceleration. After the installation, the system will reboot and thereafter it will support Intel hardware acceleration.