Blackmagic Forum

hi everyone
we are trying to setup a live production, hopefully based in the ATEM Television Studio. our planned setup: 3hd cameras, mini adapters to sdi, and a separate audio from a mixer in the venue,that has no digital out. Objective: live stream AND signal recording for possible re-edits.
We are looking at forum topics and many opinions, but these questions seem to have mixed or dubious answers.. so here they go again, hope u can help:

1 - audio:
a. whats the simplest solution to get analog audio into the atem (not embeded in a video input)?
b. does a spdif signal work, when connected directly to the atem (aes/ebu)? any downsides?
c. audio and video sync: what must we do to avoid problems here? is it ramdom? caused by the signal type? processing power?...what exactly seems to do it in the atem?

2 - signal recording:
the h.264 signal the atem produces goes out via usb. We need to have not only the option of live streaming this signal, but also record it for backup and possible re-edits. Is this possible? easy? does it need extra hardware or software?
And also, can we record a program out on a tape VCR, as well as this h264?

thanks

1) You can use a cheep analog to SPDIF converter. It works. (also a RCA to BNC converter cable needed). Video and audio are in sync. The known sync issues comes from recording by BM Media Express Software.

When using the software MxLight, you can stream and record h.264 at the same time. Maybe use an external recorder (e.g. Hyperdeck) connected directly to ATEM output.

Thomas : audio is not sync with video .. ATEM have delay .. 2 frames ?

trigital :
1/
a/ Behringer DEQ2496 http://www.thomann.de/cz/behringer_deq2 ... ve_pro.htm .. it have I/O (analog + digital) , EQ , compressor , delay .. eveything , what U need
b/ im sending SPdif from RME Fireface 400 , and works really great
c/ atem have processing delay .. its 1frame (i think) , and 1 frame are frame synchronizers .. if U have all cameras genlocked , then not need frame synchronizers ..

2/ as suggested .. www.mxlight.co.uk does do everything , what U need .. on lot of more ..
program out is only SDI .. So u need SDI to ANALOG converter , to use any analog VCR .. or use any digital recorder with SDI input .. for example BMD Hyperdeck ..

The ATEM has minimal processing delay (few lines) if you don't use the DVE. So the ATEM itself doesn't has any delay, but the sources have if they needs to be syncronized (or they arrive to the switcher already delayed).

Pytkin is very particular....

So some thoughts on the subject....

The need of audio delay depends on what the threadstarter wants to record (and its budget).

You have a video delay caused in ATEMs delay (between a few lines and one frame at TVS) and the delay at cameras outputs. If working accurate, you may use allways an audio delay unit to compensate all video delays. This delay is constant !

Some ideas:

When recording music by using microphones directliy in front so the singer, you may see the delay and you schould compensate it.
When recording a football match with micophones at the side of the field, the slow speed of sound really compensates the delay (approximately 1 frame per 15m distance).

But how to compensate ? If broadcasting live, he has to compensate live with an audio delay unit. When recording, he can compensate in the postproduction.

When using MediaExpress for recording, he may have an increasing (!) delay caused in the software .... This can't be compensated while recording and in postproduction, it's a lot of work !

So make a try !