ITVHD switching from Dolby Digital 5.1 to Dolby Digital 2.0!

AnthonyUK

I have set up a Philips BluRay home cinema 5.1 system for somebody;the set up is Sky+HD connected via HDMI to a Finlux 42FLHK905D 42" flatscreen LCD tv and the set is connected via a digital optical lead for the best sound quality to the Philips BluRay system's digital optical input.

The TV apparently decodes a Dolby Digital signal from the Sky+HD box via the HDMI connection (doesn't mention this in the book for the TV) and it DOES output the decoded full DD 5.1 audio bitstream to the BluRay home cinema on optical digital connection (or the coaxial digital connection if you are using it).

However on ITVHD when you switch to it, it outputs the non 5.1 stereo broadcasts in DPLII surround movie mode but switching between various programme output it sometimes outputs only through the two front stereo speakers!

I have tried this on all other HD channels on SkyHD and this doesn't happen at all. This 5.1/2.0 switching also happens purely on ITVHD when the Sky+HD box is connected directly to the BluRay home cinema system on optical or coaxial digital connection, but this 5.1/2.0 audio switching phenomena doesn't apparently happen on other HD channels.

None of the other channels on SkyHD do this so I can only presume there is a slight technical issue with ITV's technical provider Arquiva supplying the uplink/engineering facilities or there is a problem within ITV's network broadcast and playout centre at Grays Inn Road London.:o

NewFolder

AnthonyUK wrote: »

I have set up a Philips BluRay home cinema 5.1 system for somebody;the set up is Sky+HD connected via HDMI to a Finlux 42FLHK905D 42" flatscreen LCD tv and the set is connected via a digital optical lead for the best sound quality to the Philips BluRay system's digital optical input.

The TV apparently decodes a Dolby Digital signal from the Sky+HD box via the HDMI connection (doesn't mention this in the book for the TV) and it DOES outputs the decoded full DD 5.1 audio bitstream to the BluRay home cinema on optical digital connection (or the coaxial digital connection if you are using it).

However on ITVHD when you switch to it, it outputs the non 5.1 stereo broadcasts in DPLII surround movie mode but switching between various programme output it sometimes outputs only through the two front stereo speakers!

I have tried this on other HD channels on SkyHD and this doesn't happen at all. This 5.1/2.0 switching also happens on ITVHD when the Sky+HD box is connected directly from to the BluRay home cinema system on optical or coaxial digital connection, but happens on no other HD channels.

None of the other channels on SkyHD do this so I can only presume there is a slight technical issue with ITV's technical provider Arquiva supplying the uplink/engineering facilities or there is a problem within ITV's network broadcast and playout centre at Grays Inn Road London.:o

Does your home cinema system have a hdmi input as well as optical? It might be worth getting another hdmi cable and connecting the sky box to the home cinema, and the home cinema to the TV, to see if the 5.1 output works correctly through hdmi.
If not, then it's probably itv not transmitting 5.1, which could be intentional to save bandwidth or a technical fault. It might just be that they only send the 5.1 stream when the program has 5.1 audio, and 2.0 at all other times.

AnthonyUK

The Philips BluRay home cinema system doesn't have a HDMI input i'm afraid. I can only think that ITV mainly transmits in Dolby Digital 2.0 stereo with matrixed Dolby Surround buried in the stereo audio signal on suitable broadcast material i.e. films and some American series (a few American imports are Dolby Surround encoded and sometimes this can be full 5.1 Dolby Digital on modern series).

As ITV is a diverse network;the studios and programme makers facilities are probably not fully equipped to carry out full Dolby Digital production and audio dubbing suites in studios are not Dolby Digital 5.1 equipped as aren't transmission facilities/playout equipment.

As a result ITV mainly gets 2-channel stereo copies of everything it buys (with Dolby Surround on films and some american series where possible;even those movies that have full 5.1 have Dolby Digital soundtracks are bought as stereo copies with Dolby Surround audio) and the production companies that make programmes for itv often record location/studio sound in two-channel stereo, this can sometimes cause spurious effects within Dolby Digital decoding resulting in multichannel variability reproduction thru satellite/cable and dtt transmissions of ITVHD.

Stereo material in DPLII movie mode (dependent on microphone techniques) normally centralises speech to centre channel, sends stereo effects to the front left and right channels and extraneous sounds to the rear surround channels (this is the usual method of operation as it should do). This is normally the case on most hd channels where stereo non 5.1 DD material is broadcast;unless mono i.e. old archive programmes or old films when everything goes to centre channel only(this is normal).:beer: PS You will also get a surround effect within DPLII movie mode on some programmes where the speech is recorded centrestage and music and/or ambient sounds are in stereo this effect is often pronounced on soaps dramas and some documentaries.