7.3. TymeCode Sync

SRTMiniServer supports synchronization by SMPTE-timecode.

SRTMiniServer supports following methods for read timecode

SEI method:
used in hardware encoders like JVC-cams and Haivision encoders (see here)
used in LarixBroadcaster
LTC method:

this method is synchronization by audio-signal and may be applied with any encoders without SEI-method (Teradekt, LiveU, Kiloview etc) (see here).

Also our product SRT Streamer PRO uses this method to insert timecode when streaming multiple cameras.
VITC method: used in software encoders (see here)

Common workflow

SRT encoders do this steps:

synchronize internal clock by time-server (usually by NTP protocol).

It means all encoders have one clock: if one camera has time 11:59:59 then other cameras have same time.
send this time inside encoded feed (few methods exists).

SRTMiniServer accept this feeds, read timecode and does synchronization.

Setup

At first you need setup how to read timecode (SEI or LTC or VITC).

how to read timecode

When streams starts SRTMiniServer shows timecode. For start synchronization process you need click on "TimeCode" sync button (see below)

TimeCode Sync

press this button for start (or stop) synchronization process.

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Timecode from feed

readed timecode from feed in SMPTE format: HH:MM:SS:Frame If SRTMiniServer can't read timecode then it will shows 00:00:00:00

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Sync state

SYNC - means OK. UNSYNC - means feed can't be used in synchronization (very slow).

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What's about accuracy ?

In real test we have 1-3 frames accuracy for 60 fps feeds. It's enough in many cases.

TimeCode buffer control

Synchronization is based on small intermediate buffers in which video frames from "faster" sources expect video frames from "slower".

If during a long translation SRTMiniServer repeatedly repeats the synchronization process then these buffers can grow quite strongly. This leads to a strong lag behind realtime.

You can control this behavior by "TimeCode Max Delay" in Settings (see here)