TV3 Dolby missing center channel?

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casewindow

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#73120 9-Dec-2010 18:51

We have a Magic TV box with the 3.12 firmware. It has been running fine but in the last few days I've noticed that that center channel is not coming through on our 5.1 setup. The center speaker is definitely working (as switching to TV1 with pro-logic enabled has the center channel working fine for that configuration)

The receiver is showing Dolby Digital as being transmitted.

Some recent TV3 recordings we have do have the center channel, but I don't have any from the last few days.

Has anyone else noticed this?

cyril7

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#415233 9-Dec-2010 20:09

This has always been the case and is not a fault. Essentially TV3 transmit DD5.1 at all times but for non 5.1 material only populate the front L&R channels, they also dont use the surround flag that would force your DD decoder to engage the Pro Logic decoder, so to all intense and purposes its a 5.1 transmission with only 2 channels lit.

TVNZ on the other hand dont transmit DD so PCM is fed to your DD decoder from the AAC decode in the STB, your Receiver by default will pull the Prologic decoder into service on PCM 2channel feeds.

So the answer is, there is no issue, its been like this from day1 maybe you just never noticed, but its been mentioned several times over the years

Cyril

bfginger

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#415300 9-Dec-2010 22:17

Do upgrade to the new firmware.

casewindow

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#415366 10-Dec-2010 07:53

Cheers for that. The 'test' recorded program was a movie from TV3 with 5.1 so I guess that's why the center sound was there. I must have done this in the past when first checking out the setup of our MagicTV box. I am really perplexed though - it does seem like TV3 is a lot quieter than TV1 this week (which is I why I checked all the speakers in case they were not working properly.

With the 3.14 firmware upgrade - does it matter if you upgrade via the internet or is it best to do it via USB?

sbiddle

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#415367 10-Dec-2010 07:57

casewindow: Cheers for that. The 'test' recorded program was a movie from TV3 with 5.1 so I guess that's why the center sound was there. I must have done this in the past when first checking out the setup of our MagicTV box. I am really perplexed though - it does seem like TV3 is a lot quieter than TV1 this week (which is I why I checked all the speakers in case they were not working properly.

With the 3.14 firmware upgrade - does it matter if you upgrade via the internet or is it best to do it via USB?

AC3 should be quieter than AAC due to it's superior dynamic range.

Comparing it to TV1/TV2 in Pro Logic mode isn't a good comparision either since the bulk of the content on TV1/TV2 isn't in Pro Logic anyway.

old3eyes

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#415375 10-Dec-2010 08:30

sbiddle:
casewindow: Cheers for that. The 'test' recorded program was a movie from TV3 with 5.1 so I guess that's why the center sound was there. I must have done this in the past when first checking out the setup of our MagicTV box. I am really perplexed though - it does seem like TV3 is a lot quieter than TV1 this week (which is I why I checked all the speakers in case they were not working properly.

With the 3.14 firmware upgrade - does it matter if you upgrade via the internet or is it best to do it via USB?

AC3 should be quieter than AAC due to it's superior dynamic range.

Comparing it to TV1/TV2 in Pro Logic mode isn't a good comparision either since the bulk of the content on TV1/TV2 isn't in Pro Logic anyway.

Any update on when TVNZ 1& 2 are going AC3?? I seem to remember it was "soon"

Regards,

Old3eyes

ZollyMonsta

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#415380 10-Dec-2010 08:43

sbiddle:
AC3 should be quieter than AAC due to it's superior dynamic range.

Comparing it to TV1/TV2 in Pro Logic mode isn't a good comparision either since the bulk of the content on TV1/TV2 isn't in Pro Logic anyway.

Not if the box provider is adhering to a specified Dolby service notice which Freeview stick by.
If that is implemented in the set top box (in the wide range of devices it's not) then the audio levels are no different between AAC and Dolby.

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robjg63

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#415406 10-Dec-2010 09:51

cyril7: This has always been the case and is not a fault. Essentially TV3 transmit DD5.1 at all times but for non 5.1 material only populate the front L&R channels, they also dont use the surround flag that would force your DD decoder to engage the Pro Logic decoder, so to all intense and purposes its a 5.1 transmission with only 2 channels lit.

TVNZ on the other hand dont transmit DD so PCM is fed to your DD decoder from the AAC decode in the STB, your Receiver by default will pull the Prologic decoder into service on PCM 2channel feeds.

So the answer is, there is no issue, its been like this from day1 maybe you just never noticed, but its been mentioned several times over the years

Cyril

Thank you Cyril ! - First time I have seen it explained so well. Bought a home theatre a year or so ago and noticed that the DD5.1 was somewhat 'empty' - ie just the 2 channels when they were broadcasting a non-5.1 soundtrack. I found that a real pain so just set the default to AAC.

So if they broadcast that surround flag I wouldnt have to fiddle with my amp to get their 2 channel programs to use the other speakers?

I have a Denon receiver and cant find any options (that I understand) to handle (ie force the other speakers to be used) the 2 channel feeds over the DD5.1 without screwing it up for genuine 5.1 soundtracks.

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cyril7

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#415414 10-Dec-2010 10:07

I understand from one of the sound guys who works for the ABC (Oz) where they do exactly as TV3 does is that to operate the surround flag causes some DD decoders to make abrupt disruptions in the transistion, which is probably not an issue and not noticed when you are dicking around shoving DVD into a player and playing with the DVD menus to start a movie, but quite distrubing when watching continuous TV, hence most broadcasters have elected to not play with the surround flag. I guess also its another thing that has to be coordinated in the playout continuity suite where there are already plenty of balls to juggle.

Maybe someone from one of the broadcasters (a couple do lurk here) might shed some light on the real reason.

Cheers
Cyril