Poor subtitling
Charenton
Posts: 1,427 Forum Member
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Is anyone else experiencing subtitling appearing well in advance of a character saying the words? This is happening to me mainly on some of the the minor Freeview channels but it also occurs on Ch5 occasionally.
The subtitles generally begin in synch with the spoken word then gradually start to appear early. They will then disappear for a time then reappear once more in synch. This goes on throughout the programme. It's most confusing when subtitles appear for characters in the following scene who have yet to appear on screen and when they do you forget what they were saying.
It would be nice to know if this is a local problem or a national one. I receive programmes from the Sutton Coldfield transmitter in the MIdlands.
The subtitles generally begin in synch with the spoken word then gradually start to appear early. They will then disappear for a time then reappear once more in synch. This goes on throughout the programme. It's most confusing when subtitles appear for characters in the following scene who have yet to appear on screen and when they do you forget what they were saying.
It would be nice to know if this is a local problem or a national one. I receive programmes from the Sutton Coldfield transmitter in the MIdlands.
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Comments
What model is it......?
Try doing a mains repower on it. Leave it depowered for about 30 secs
The reason is that many subtitle decoders get very confused over the presentation time stamp... PTS ...
A packet may arrive with a PTS in the past which means display at once or it may arrive some time in advance and thus needs to be delayed before display.- this is preferred operation...... drop subtitle packets in just before the video to which it refers.
My STB is a Humax HDR-Fox T2 PVR. If it is my STB why are the BBC subtitles always spot on when a number of the others aren't? This problem has only recently started.
While Technologist is indeed correct that some set top boxes can get confused and the synchronicity between video, audio, and subtitles can get lost, this is only possible to a fairly limited extent. (After all, subtitles are only broadcast at around-the-same-time as the video which they relate to, so a set top box wouldn't be able to drift your subtitles 30 seconds ahead of the video, for example, because to do so it would be showing you subtitles before they had even been transmitted.)
It's far more likely to be a problem at the channel's end, and hence, the same for everybody. Times and dates mean you can ask the channel themselves to check - and if their response is not to your liking, you can go to OFCOM and make sure they treat it seriously.
Also, the more information you gather about what programmes and channels you see with this problem, the easier it would be to identify the common factor. Although it /could/ be your STB, I'd be very surprised if it was.
But as ofcom is very strict on subtitling performance .... I am sure that the playout and code and mux are looking at them from time to time.
It is also unlikely in play out that there are regular drifting....
It is more likely that a late edit is done which disturbs the timecode
which means that all succeeding subtitles are off....
The BBC has been very good with subtitles for arround 20 years when I got them to acknowledge that every played out programme has Video audio and subtitles
Why are subtitles so erratic in their appearance? This is especially true since all tv went digital. It's almost impossible to follow them on any channel without there being gaps of several sentences, usually the previous subtitles just sit there, vanish then update. I've noticed this mostly on Freeview, but that's only because I only watch Sky at my parents house.
It affects all the channels I watch at all times of the day -
BBC 1,2,3 and 4
Dave, Yesterday and Drama
ITV 2 and 4 (presumably 1 and 3 but I don't watch those)
Channel 4 and Film4 seem OK but I don't really watch those enough with subtitles to find a problem.
The problem has occurred on many devices including a Samsung Smart tv, Panasonic Viera, Top Up tv stb, and a Matsui (tutv) stb.
Try repowering your stb/TV
At a technical level there should be no hanging subtitles on DTT ,or Freesat, as DVB ST has a time out for the life of a subtitle ... However few broadcasters specify this to their code and mux contractor .....
But with a lot of ofcom scrutiny on subtitle performance all broadcasters are looking at it.. And certainly the BBC who has very rarely taken its or Red Bees or Atos eye off the ball ..should be perfect.
What you describe is classic confused decoder ..... But I am surprised that you have it on so many devices
It's happened for years and it amazes me that so many devices suffer from the same problem. I do occasionally reboot them but it doesn't seem to make any difference, to be honest it's almost 'normal' to me that subtitles on digital tv are pretty much awful and at some point will drift then stop.
Could a low signal be part of the problem? I've seen it occur from Emley Moor and the Chesterfield relay and have lived around the Chesterfield area and it's villages.
But I find it indefensible that sets stb have these problems now...
They did not seem to have registered in this ofcom work
http://stakeholders.ofcom.org.uk/binaries/consultations/subtitling/statement/sampling-report.pdf
It also has some notes on broadcaster getting things wrong... This has the symptom of things stopping .. Not drifting out of sync then coming back .....
I will have a chat with DTG sometime in the next few weeks
If you watch any significant amount of subtitles across any number of channels, though, it does become very apparent that actually a lot of balls are being dropped. The UKTV channels, for example, have had an assortment of weird and wonderful problems for longer than I can remember.
I had a look a few minutes ago to see if they were still happening, and they still are. A documentary on Yesterday with all the subtitles positioned hard-left on screen. A comedy show on Dave with all the subtitles accompanied by long black bars hanging off the right-hand side of each line of text. Used to see both of those problems a lot (and sometimes simultaneously) on Alibi, but it looks like they're reproducing. The fact that these go unfixed for months, even years at a time, makes you wonder if anyone is paying any attention at all.
I think the problem is that people just don't complain enough - and if my personal experience is anything to go by, when they do, their complaints are either ignored, or get answered by somebody who doesn't know the first thing about subtitles and can't answer the question properly.
My bold
I'd forgotten about the long black bars and weird positioning. Also on BBC Three HD the subtitles are tiny, though I suspect this is because of the increase in resolution and what looks like 'normal' subtitles in SD at 720 x 576 will look smaller at 1080 x 1920 on a 37" screen.
And when you think about these the video is not the most important to the viewer.....
Others, because if the way in which the workflow works , tend to see subtitles as a last minute bolt on...... And thus the systems are not so robust and the attitudes are not as wide ranging.
On the whole it works and so there is little need for technical expertise , so there arn't any systems specialists when it all goes wrong.
However the uk does have the two leading manufacturers of subtitling kit .....
(Like teletext is)
They are run length encoded bit maps typically with a bit depth of 4 or 8......
And some coders still don't anti alias !!!!!!
This is so that the broadcasters can influence the fonts ..
Although ofcom mandate Tiresias there are many flavours ....
However, I switch of in disgust when there is an obvious misinterpretation of something, due to the subtitlers lack of knowledge and lack of checking.
And if it's live subtitling then forget it - unless your looking for a laugh.
But I'd like to congratulate STV News for having pre-prepared subtitles, something which the BBC has difficulty achieving.
And all snaked subtitles are being blocked up and time aligned on iPlayer
Some if you may remember that BBC news used prepared subtitles in the late 1990s ...
This was discontinued because of a change of live system and the problems iof changing over to the steno for live items..... It takes time to get started with chording , which made the subtitles later..... And someone to work the switch !
Now with the new real time subtitling system it as a lot easier ....
I just thought it was my freeview box!...... it only cost me about £90 ish from Argos and I have had it a few years now so though it was on its way out!......
But maybe it is just the general Freeview itself that is crap!............
I live in north bucks but have no idea what transmitter I receive from!.........
I've noticed this a lot too, and I'm in mid-Wales.
Can I just point to the link in post#9
Real time subtitling is less reliable /accurate than prepared for obvious reasons....
I have given more details on BBC POV
http://www.bbc.co.uk/dna/mbpointsofview/NF1951566?thread=8462586#p120669652
But there should never be a prepared subtitle up referring to the next shot... (Except perhaps in news)
It does puzzle me that the timing is so very variable..... And that they appear to reset the timing after a break ...
It is possible that when a programme has been edited , the time code is relaid and so the subtitles are out by a consistent amount ...
As a matter of interest, could this problem be caused when watching a recorded programme if the subtitles were perfect when the programme was transmitted live? I ask as I record most programmes I watch that have adverts in them so I can skip them.
I don't normally get this problem with BBC, ITV1, 4 & 5 recordings, just the minor Freeview channels..
I started watching George Gently at 8.30pm. The subtitling was woeful. At times it was up to 10 seconds ahead of the characters. Then they would stop and resume in sync. This went on throughout the entire programme. On the other hand the subtitling on Grantchester was spot on throughout.
This suggests to me the problem of poor subtitling is down to the broadcaster.
I know from past experience if I complain to UKTV about the Drama channel subtitles they will eventually reply that they can find no errors in their subtitling.
I have complained to OFCOM in the past and nothing seems to have improved.
You mention seeing similar problems on both Drama and ITV3 - which does make me wonder if a common factor could be the Freeview multiplex (COM4) which they broadcast on.
I'll come back when Inspector Gently has done his bit.
I've only watched the first 50 minutes so far - I haven't noticed any problems with the synchronisation of the subtitles yet, but what is very quickly apparent is that UKTV's "subtitles all flush-left" problem is very much in evidence on Drama too. Two screenshots to illustrate:
http://imgur.com/xLbSZa8
http://imgur.com/kwSTMz6
What I also see throughout the programme is lots of bit errors causing character substitutions - I to M, E to U, L to N, S to 1/4, R to Z, Y to 3/4, and so on. Another example:
http://imgur.com/8DbXSwj
In the old days that would have been blamed on the viewers' reception or equipment, but since these are DVB subtitles, that excuse won't hold water, this is definitively a signal path problem on the broadcaster's end, as nothing else can cause substitutions like that.
As I say, the sync looks broadly OK, perhaps the subtitles are a little behind the audio and shot changes, but that might be artefacts of my recording/playback. But the rest of the problems are definitely broadcast-side, absolutely no question at all.
Someone needs to inform UKTV that they need to speak with Arqiva ...
For the bit errors ...., they are gloriously random ...
See 15.6.1. In en 300 706
The set left may be in the origination system as the justification code in the tech 3264 files is not being read ...
Can I just point out the prat trap which means the black subtitle extending to the right ...
To start a subtitle box you have double transmission of start box command
But the box is terminated by a single end box .... But many teletext Tx systems have
double transmission of end box ,,,, and thus the teletext to DVB st unit erroneously looks fir two end box commands ... 12.2 of. En 300 706
I'm disappointed to see the poor synchronising of Drama's subtitling isn't across the board. I could understand it if it happened to me on all channels, but it doesn't. As I said earlier the George Gently subtitles were awful but Grantchester, recorded at the same time, were perfect. Generally I get no subtitle problems with the main channels, BBC1,2; ITV1, Ch4 & Ch5. Maybe the problem is at my transmitter at Sutton Coldfield.
I also noticed the poor spelling and fractions appearing in place of some letters during George Gently. I could live with subtitles being a second or two late but 10 seconds earlier is impossible to follow.
Next time I am watching a live programme with poor subtitles I will switch from my PVR to the TV's own Freeview tuner to see if the subtitles are poor on that too.
I have asked Sutton Coldfield transmitter if there's any reason for this problem I'm having.