how could this tech glitch happen?
- Thread starter powerdog
- Start date
Rick Meyer
Veteran
Well, remember even with a live broadcast, there is always a delay. So for there to be a delay is normal. To be out of sync is not. Perhaps their live feed for the audio was patched differently than the feed for the video?
Rick
Rick
Anhar_Miah
Veteran
don't forget that is not just the transmission, if could have occured at your end too, if you was watching DVB-t/s/c then if just could have been a slight loss of data due to signal variance, and sometimes very rarely (even though MPEG2 is really quite robust) some sync issues could have arisen. Its not impossible.
Anhar_Miah
Veteran
oohh, I see, for that I don't know, strange studio equipment bah !
mikkowilson
Steadi-Guru
Due to the way that digital compression works, there can be all sorts of gramlins in these systems that drive teh techs a lot more nuts than the viewers. (Trust me.)
A lot of these systems now use MPEG2 with various modulation and encapsulation meathods. There's Plenty of MPEG4 and a good mix of Analog in there too.
The oen big bonus with Analog is that Live is Live. Through the whole chain with no (notable) delay. With digital there are encodes and decodes all over the place, and things happen at different speeds in different systems, and sometimes this can lead to sync losses. Some system seven operate out of sync and rely on delay equipment to re-syncronize everything at some convinient place.
There is no one answer to what might have cahse what you saw. A diversity reciver might have soiwtched oen feed to another signal path bouncing off a building, or tehre coudl have been a routing issue with an operator mistakinly running the field audio through a delay meant for a studio source (also possible), etc, etc.. who knows.
The IT world in Broadcasting is a tough mix. Computers are all about "now*" (*with a bit of processing time, lag, etc, so as fast as possible) while the traditional broadcast environment is abotu LIVE. As in Right now, not 2ms later (as that will horribly throw off the colors..), but right now real time live non stop.
I was recently on a project to create a path for a TV signal to a broadcat transmitter. A local Telecommunications company gave us an offer of a great system with (about) 97% uptime. Very reasonable for any computer application, ans those momentarry glitches go unnotied as the data is fed though a moment later. However toally unnaceptabel for TV. 97%, that' 3% downtime. .. some 20 secconds or so a DAY of signal loss, which in the world of big dollars per secconds, that's absurd. It ammounted to some hours a year of the station beeing offline. We went with an analog transmission system along copper coax cable.
In the digital world, everything is possible.
- Mikko
A lot of these systems now use MPEG2 with various modulation and encapsulation meathods. There's Plenty of MPEG4 and a good mix of Analog in there too.
The oen big bonus with Analog is that Live is Live. Through the whole chain with no (notable) delay. With digital there are encodes and decodes all over the place, and things happen at different speeds in different systems, and sometimes this can lead to sync losses. Some system seven operate out of sync and rely on delay equipment to re-syncronize everything at some convinient place.
There is no one answer to what might have cahse what you saw. A diversity reciver might have soiwtched oen feed to another signal path bouncing off a building, or tehre coudl have been a routing issue with an operator mistakinly running the field audio through a delay meant for a studio source (also possible), etc, etc.. who knows.
The IT world in Broadcasting is a tough mix. Computers are all about "now*" (*with a bit of processing time, lag, etc, so as fast as possible) while the traditional broadcast environment is abotu LIVE. As in Right now, not 2ms later (as that will horribly throw off the colors..), but right now real time live non stop.
I was recently on a project to create a path for a TV signal to a broadcat transmitter. A local Telecommunications company gave us an offer of a great system with (about) 97% uptime. Very reasonable for any computer application, ans those momentarry glitches go unnotied as the data is fed though a moment later. However toally unnaceptabel for TV. 97%, that' 3% downtime. .. some 20 secconds or so a DAY of signal loss, which in the world of big dollars per secconds, that's absurd. It ammounted to some hours a year of the station beeing offline. We went with an analog transmission system along copper coax cable.
In the digital world, everything is possible.
- Mikko
morten
Well-known member
from a production standpoint this is a fairly standard occurence. the most normal reason for live-eye sync problems is that all the content (video and audio) has to go by microwave link from the truck to the main station through the mixers and back out. in this process about 4-5 different departments have a chance to poo poo things up pretty bad:
the camera guy
the truck operator (if there is one)
the distribution operator that receives the signal and sends it where it's supposed to go
the people in the main control room
master control
the sync problem could arise in any of these locations and normally all the involved will blame everyone else rather than try to fix it.
in my case (I broadcast a live show from Vancouver via digital link to Telus TOC in Vancouver, optical cable to TOC Calgary, optical cable to CTV in Toronto and from there to the network) we have a constant sync problem with either the audio or the video always arriving out of sync. one of the problems was that at some point in the chain someone used a huge 100 foot cable in a patch bay instead of a standard 2 foot one (!!!). another problem was that the audio was being converted from digital to analog and back to digital at each stop while the video was just destroyed (I mean converted) in Vancouver and sent straight to Toronto.
with all the eqipment and all the people working on a live show it's actually a miracle that things usually work the way they are supposed to. but just wait: once everyone starts switching to HD you're going to see even more absurd problems arise - like letterboxing and squeezing on the wrong signals and endless artifacting and digital audio problems. fun fun fun
mor10
the camera guy
the truck operator (if there is one)
the distribution operator that receives the signal and sends it where it's supposed to go
the people in the main control room
master control
the sync problem could arise in any of these locations and normally all the involved will blame everyone else rather than try to fix it.
in my case (I broadcast a live show from Vancouver via digital link to Telus TOC in Vancouver, optical cable to TOC Calgary, optical cable to CTV in Toronto and from there to the network) we have a constant sync problem with either the audio or the video always arriving out of sync. one of the problems was that at some point in the chain someone used a huge 100 foot cable in a patch bay instead of a standard 2 foot one (!!!). another problem was that the audio was being converted from digital to analog and back to digital at each stop while the video was just destroyed (I mean converted) in Vancouver and sent straight to Toronto.
with all the eqipment and all the people working on a live show it's actually a miracle that things usually work the way they are supposed to. but just wait: once everyone starts switching to HD you're going to see even more absurd problems arise - like letterboxing and squeezing on the wrong signals and endless artifacting and digital audio problems. fun fun fun
mor10
Morten, very complete explanation. Thanks! From what you say, it seems like they may have known he was out of sync, but not had time in his few minutes on-air to fix the prob.
Interesting...they do that remote b'cast stuff all the time, but this is the first time I've seen them have the sync issue.
Interesting...they do that remote b'cast stuff all the time, but this is the first time I've seen them have the sync issue.