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Last night of the proms - HD sound out of sync



 
 
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  #21  
Old September 15th 14, 07:03 AM posted to uk.tech.digital-tv
PeterC
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Posts: 812
Default Last night of the proms - HD sound out of sync

On Sun, 14 Sep 2014 23:41:52 +0100, Max Demian wrote:

"PeterC" wrote in message
...
On Sat, 13 Sep 2014 21:40:02 +0100, Jeff Layman wrote:

Just watching the Last Night of the Proms. Lip sync is definitely out on
BBC1HD, but ok on SD. Sound slightly leads video.

This is with a Panasonic PVR DMR-HWT130. Anyone else notice this?


Katie Dereham did apologise for problems with sound early in the evening.
This was recorded via Freesat on Hummy PVR.


I think that was about the appalling glitching in the HD sound during the
first 30 minutes or so. Fortunately I had also recorded it in SD with my DVD
recorder.


I didn't bother with the sync as I was reading at the same time - sort of TV
without pictures (there ought to be a name for that).
--
Peter.
The gods will stay away
whilst religions hold sway
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  #22  
Old September 15th 14, 08:21 AM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
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Posts: 2,246
Default Last night of the proms - HD sound out of sync

On Mon, 15 Sep 2014 08:03:18 +0100, PeterC
wrote:

I didn't bother with the sync as I was reading at the same time - sort of TV
without pictures (there ought to be a name for that).


If you were reading from a gadget (rather than a book) while watching
TV, then apparently the word for that is "multiscreening". It's a new
thing that young people do, because they can. (Or because they'd have
to stop using their gadgets for more than a few minutes, and that
would never do).

Rod.
  #23  
Old September 15th 14, 10:35 AM posted to uk.tech.digital-tv
Max Demian
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Posts: 3,970
Default Last night of the proms - HD sound out of sync

"Jeff Layman" wrote in message
...
On 14/09/2014 23:39, Max Demian wrote:
The 1998
Panasonic CRT I had in-between never needed anything - it even
compensated
for the dark scenes sometimes found in films made to be viewed in the
cinema.


Oh, you mean like the bits in between the adverts in "The Suspicions of Mr
Whicher"... ;-)


Yeah. Another thing I don't understand about made for TV dramas is why they
are sometimes made in 21:9 (such as Utopia). Who has a 21:9 TV?

--
Max Demian


  #24  
Old September 15th 14, 11:53 AM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
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Posts: 2,246
Default Last night of the proms - HD sound out of sync

On Mon, 15 Sep 2014 11:35:34 +0100, "Max Demian"
wrote:

The 1998
Panasonic CRT I had in-between never needed anything - it even
compensated
for the dark scenes sometimes found in films made to be viewed in the
cinema.


Oh, you mean like the bits in between the adverts in "The Suspicions of Mr
Whicher"... ;-)


Yeah. Another thing I don't understand about made for TV dramas is why they
are sometimes made in 21:9 (such as Utopia). Who has a 21:9 TV?


I suppose it's all part of that "style over substance" thing again.
Wacky camera angles, pointless photographic or electronic effects,
lots of gratuitous violence, and the apparent inability of any of he
characters to make any utterance without using the word "****" or one
of its derivatives regardless of what the plot requires to be said or
how any real person would say it. I gave up after a couple of
episodes, thinking at first that I should give it a chance to show
that perhaps there was a real plot after all, but then realising that
all the gimmickry was just the usual attempt to conceal the fact that
there wasn't.

Perhaps the best you could say is that making this as a 21:9 programme
for 16:9 screens ensures that less of the screen is wasted.

Rod.
  #25  
Old September 15th 14, 03:38 PM posted to uk.tech.digital-tv
PeterC
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Posts: 812
Default Last night of the proms - HD sound out of sync

On Mon, 15 Sep 2014 09:21:31 +0100, Roderick Stewart wrote:

On Mon, 15 Sep 2014 08:03:18 +0100, PeterC
wrote:

I didn't bother with the sync as I was reading at the same time - sort of TV
without pictures (there ought to be a name for that).


If you were reading from a gadget (rather than a book) while watching
TV, then apparently the word for that is "multiscreening". It's a new
thing that young people do, because they can. (Or because they'd have
to stop using their gadgets for more than a few minutes, and that
would never do).

Rod.


antediluvian a book /
--
Peter.
The gods will stay away
whilst religions hold sway
  #26  
Old September 15th 14, 05:58 PM posted to uk.tech.digital-tv
alan_m
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Posts: 189
Default Last night of the proms - HD sound out of sync

On 14/09/2014 10:51, Andy Furniss wrote:



I only recorded the first few minutes of BBC2 HD and SD for geek reasons
and the HD sound was ruined by constant glitching.


Haven't the BBC a poor history of getting the sound in sync on the
outside broadcast of the PROMs? I seem to remember that one year the
picture was so far ahead of the audio at the broadcast end and no STB
had the ability for time travel to correct it
--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk
  #27  
Old September 15th 14, 08:49 PM posted to uk.tech.digital-tv
Andy Furniss[_3_]
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Posts: 130
Default Last night of the proms - HD sound out of sync

Jim Lesurf wrote:
In article , Andy
Furniss [email protected] wrote:
PeterC wrote:
On Sat, 13 Sep 2014 21:40:02 +0100, Jeff Layman wrote:

Just watching the Last Night of the Proms. Lip sync is
definitely out on BBC1HD, but ok on SD. Sound slightly leads
video.

This is with a Panasonic PVR DMR-HWT130. Anyone else notice
this?

Katie Dereham did apologise for problems with sound early in the
evening. This was recorded via Freesat on Hummy PVR.


Maybe the lipsync/quality issues later were the result of the
panic/workarounds that were needed to fix the initial glitching.


I only recorded the first few minutes of BBC2 HD and SD for geek
reasons and the HD sound was ruined by constant glitching.


FWIW I was occupied with other matters last night. So I've recorded
the SDTV BBC1 Freeview second half, but ignored the first half on TV
as we now get the dumbed down 'Scottish Last Night' on BBC2. Plan to
listen to the R3 320k stream during the week. Our internet connection
isn't reliable enough over the weekend to listen without breaks.


Ouch that you can't stream 320kbit. Is it resyncs or really not having
the bandwidth or just linklayer packet loss - if it's the latter I guess
you could throw a couple of meg buffer at it like -

mplayer -cache 2000 -playlist
http://www.bbc.co.uk/radio/listen/live/r3_aaclca.pls

though I know you have other ways anyway.

In other news - I finally found where the aac mixdown meta is. As I
recall you speculating it's in it's in some dvb etsi doc. It also
specifies heavy compression, though as ffmpeg doesn't parse the block at
all I haven't actually seen what's broadcast yet. It was easy enough
adding debugging to see normal drc but writing a parser to see the rest
is something which may take some time to get round to :-)

I wonder whether TVs use heavy compression (if present) - anyone seen a
"midnight mode" button on aac kit, like some dvd players have (which I
guess uses the heavy compression meta data in ac3).

  #28  
Old September 16th 14, 08:46 AM posted to uk.tech.digital-tv
Jim Lesurf[_2_]
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Posts: 4,326
Default Last night of the proms - HD sound out of sync

In article , Andy
Furniss [email protected] wrote:
Jim Lesurf wrote:


FWIW I was occupied with other matters last night. So I've recorded
the SDTV BBC1 Freeview second half, but ignored the first half on TV
as we now get the dumbed down 'Scottish Last Night' on BBC2. Plan to
listen to the R3 320k stream during the week. Our internet connection
isn't reliable enough over the weekend to listen without breaks.


Ouch that you can't stream 320kbit. Is it resyncs or really not having
the bandwidth or just linklayer packet loss


I'm not certain of the details. But in practice the behaviour varies.
Sometimes I just get pauses (of many seconds). Sometimes the stream halts
and I get the 'whirling arrow' on the flash display until I either quit it
or it gives up and tells me my connection may not be good enough.

When I test the connection I still tend to be told the bandwidth is around
3 mbps. Which should be fine. So the problem seems to be other traffic
somewhere along the way is meaning I'm not getting enough reaching my local
distribution point.

As a result evenings are unreliable and the weekends during the day are
often also hopeless. Around mid-day on weekdays is generally fine. Although
last week was difficult. Maybe because the new students were arriving and
settling in. The ones in the main uni halls have connections provided by
the uni. But I don't know if they go out via superjanet or sponge off the
local telco shared with the town. Whatever, the students in private HMOs
probably also also all emailing home because they forgot socks, etc. :-)

During weekdays we can *almost* watch SDTV from the iplayer without too
many pauses. So the problem presumably isn't 'the last mile'. That said,
maybe its other people in our road. The system here is pretty creaky.
They've been installing fibre to some cabinets. But no sign of it to ours.

- if it's the latter I guess
you could throw a couple of meg buffer at it like -


mplayer -cache 2000 -playlist
http://www.bbc.co.uk/radio/listen/live/r3_aaclca.pls


though I know you have other ways anyway.


I'll experiment with that, although a bit late now for live Proms. :-)

In other news - I finally found where the aac mixdown meta is. As I
recall you speculating it's in it's in some dvb etsi doc. It also
specifies heavy compression, though as ffmpeg doesn't parse the block at
all I haven't actually seen what's broadcast yet. It was easy enough
adding debugging to see normal drc but writing a parser to see the rest
is something which may take some time to get round to :-)


I'll be interested to see how you get on! Afraid I bogged down in trying to
understand the parsing beyond the first couple of levels. So have just done
other things my small brain can cope with more easily.

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

  #29  
Old September 16th 14, 12:53 PM posted to uk.tech.digital-tv
tony sayer
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Posts: 5,001
Default Last night of the proms - HD sound out of sync


When I test the connection I still tend to be told the bandwidth is around
3 mbps. Which should be fine. So the problem seems to be other traffic
somewhere along the way is meaning I'm not getting enough reaching my local
distribution point.



We've just gone from 30 to 100 meg on VM but I can't say it seems any
faster. Mate of mine reckons that some data centres don't have that much
connection capacity anyway.

Seems the rest of the net has some catching up to do;!.

And FWIW we sometimes have "reception" problems off the net on BBC
services!...
--
Tony Sayer


  #30  
Old September 16th 14, 04:53 PM posted to uk.tech.digital-tv
Johny B Good[_2_]
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Posts: 853
Default Last night of the proms - HD sound out of sync

On Tue, 16 Sep 2014 13:53:26 +0100, tony sayer
wrote:


When I test the connection I still tend to be told the bandwidth is around
3 mbps. Which should be fine. So the problem seems to be other traffic
somewhere along the way is meaning I'm not getting enough reaching my local
distribution point.



We've just gone from 30 to 100 meg on VM but I can't say it seems any
faster. Mate of mine reckons that some data centres don't have that much
connection capacity anyway.


Welcome to the wonderful world of VM's excess download provisioning!


Seems the rest of the net has some catching up to do;!.


I think you'll find that most web hosts on the WWW will fail
abysmally to keep up with even a 10Mbps VM cable connection.


And FWIW we sometimes have "reception" problems off the net on BBC
services!...


That's just a clear demonstration that the "internet" has ample
bottlenecks all of its own beyond that of your local ISP's server
farms.

This isn't a new phenomena either. I well recall those times, about
14 or 15 years ago, when I had to put up with the rather pathetic 1 to
3 KB/s download speeds[1] from certain Taiwanese MoBo makers websites'
support pages on a 128/150 Kbps 'broadband connection'[2]. Even a
humble dialup connection[3] would have had download capacity to spare!

Naming and shaming, the worst offender was PC Chips (downloading
drivers for my customers' PCs). However, other MoBo makers were nearly
as bad (Asus/Asrock. Jetway, Gigabyte, MicroStar etc). I just assumed
that Taiwan wasn't very well provisioned on its international circuits
to the rest of the "World Wide Wait"(tm).

[1] Or even slower! dropping down to just a few hundred B/s at times.
The only upside of using BB instead of Dialup was that I could 'wait
it out'[4] without worrying about penny per minute charges and still
browse the WWW and download from other faster sites (as well as not
blocking the phone line for its intended use).

[2] This was the original "Tier One" service level from NTL.
Successive 'Free Speed Upgrades' ever since have resulted in the
current 30Mps (soon to be (_yet_ again!) upgraded to 50Mbps).

Unless you're hitting the upload limit hard, you may well be
'downgrading' back to the "Tier One" service after the promised
upgrade to 50Mbps has completed. :-)

[3] Yes, I used to see download speeds in excess of 5KB/s (just!) when
downloading from better connected sites when using a "56K" V .90 modem
over a 45/48Kbps connection. My needs, like most of my contemporaries
back then, were far far more modest than our current needs today.

I didn't mind the penny a minute connection charge when I knew I was
"maxing out" the connection, that was just the price you had to pay (a
damn sight cheaper than an "Assholes' On Line"(tm) connection) if you
wanted to be in the game.

[4] I think, even back then, I was enjoying the benefit of Opera's
download manager which allowed me to stop and restart a download
session in order to tickle the fickle server in question into resuming
a stalled download.

It was as if the servers in question were behaving like a tired old
man nodding off in the middle of a long winded story, requiring a
gentle prod every now and then to stir him from his slumber.

It might seem like I'm anthropomorphizing the technology when I use
such analogies. Believe me, that's the last thing I'm doing. I'm
actually passing comment on the feeble mindedness of the developers
responsible for such shoddy coding.
--
J B Good
 




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