Harmonic ELECTRA VS, User Manual

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Appendix A ’Technical Specifications’ — Common Specifications
538 Electra VS - Version 05.10
User Manual - Rev. A
IP TV Latency
The formula to obtain the latency is as follows:
Latency = <input latency> + <Coder delay> / <Output frame rate> +
<Decoder delay> + <Optional processing latency>
With:
 Input latency:
 SDI input: 0.64 second.
 TS/IP input: 1.3 second.

Coder delay: this is the value configured in the encoders (see section
’H.264 AVC Encoder’ on page 311, section ’H.265 HEVC Encoder’ on
page 315, section ’MPEG-2 Encoder’ on page 309). The values are
identical for the three encoders:
 Standard : 55 frames.

Short : 41 frames.
 Ultra-short : 26 frames.
 Decoder delay: this is the value configured in the encoders (see
section
’H.264 AVC Encoder’ on page 311, section ’H.265 HEVC
Encoder’ on page 315, section ’MPEG-2 Encoder’ on page 309). The
value is fixed to 1 second for MPEG-2 encoding.
 Output frame rate: it depends on the input frame rate, and on the
optional frame rate adaptation you may have added.

Optional processing latency: it depends on the video processing you
have configured. It is null if there is no preprocessing.
Examples (without any video processing):
 SDI input, H264, 25 fps, delay set to Standard : 4.3 seconds.
 SDI input, H264, 25 fps, delay set to Short : 3.3 seconds.
 SDI input, H264, 25 fps, delay set to Ultra-short : 2.5 seconds.

SDI input, H264, 60 fps, delay set to Standard : 3.1 seconds.
 TS/IP input, H264, 60 fps, delay set to Standard : 3.7 seconds.
In Statmux mode, the formula to obtain the latency is as follows:
Latency = <input latency> + 61 / <Output frame rate> + 1.2
<Optional processing latency>
Audio transcoding (radio, or TV with pass-through video), TS/IP input /
TS/IP output:
 Latency is approximately 2 seconds.