BT TV Box Pro - comments/questions

[HS6]

If it was a conscious decision to implement the surround sound in the way it's been done.. would you happen to know why,  and what benefit it provides?

It doesn't seem logical to me to develop something with less function by ignoring an obvious requirement (unless there is a clear reason for doing so).

All my previous BT TV set top boxes have delivered 5.1 surround sound decoding information with stereo transmissions, as does my current Apple TV 4k box. I'm baffled as to why Sagemcom would adopt a different methodology.

[DarrenDev]

There is only 1 Pro box - we don't know why "Type B" has been added to newer labels (possibly added when boxes started being shipped with WiFi enabled by default), however I've spoken directly to the hardware manager and he assures me that only 1 variant of the hardware has ever been created.  My original Pro box is over 2 years old now (it was a LONG trial) and is still exactly the same hardware as the new box I received a couple of weeks ago (which you're right - also has a Type B label).

There are many versions of the firmware out there, depending on trials currently running, pilots, and stages of full rollout.  Announcements are generally only made when there are features of interest/importance.

[DarrenDev]

The explanation I have:

The STB always does transcoding of some sort, even in the G4/G5 (DTR-T2xxx and DTR-T4xxx). The transmitted format of stereo is AAC (on HD channels) and this cannot be transported over HDMI so it has to be decoded to PCM or transcoded to DD+.

If the HDMI output is set to ‘Surround’ the output is transcoded to DD+ (Dolby Digital Plus, E-AC3). This is for surround sound amps and TVs that support DD+. If the source is 5.1 channel then the output is 5.1 channel DD+. If the source is 2 channel then the output is 2 channel DD+. Some content and / or amplifiers generate pseudo 5.1 channel from 2 channel DD+ depending on the mode the amplifier is in.

If the HDMI output is set to ‘Stereo’ then the output is transcoded to PCM stereo irrespective of the source. This is for TVs and amplifiers that do not support DD(+).

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It sounds like the logic is based entirely around the expectation that amps could still apply pseudo surround when the input is 2 channel DD+.  That expectation has subsequently been proven wrong on this forum.

The ideal solution would be that where the source content is 2 channel, it should follow the PCM route as previous boxes did. I don't know how hard this would be to do now, but I raised this as an issue (change request) in August, and it'll be prioritised along with the other features being developed on the Pro box.

[HS6]

Thank you for your reply DarrenDev..

I'm new to this forum (actually I'm new to any forum), so have not seen your earlier posts on this topic.

It's encouraging that the submitted a change request about this in August and so perhaps something will get done after all. 

It was also helpful that you explained what's wrong with the Pro Box surround sound implementation in technical terms, and what the ideal solution should be (ie where the source content is 2 channel, the box should output PCM as previous boxes did).

Now i'll be able to use the correct technical terminology when talking to others.

Thank you and best regards HS6

[Welsh1]

Hi @DarrenDev you seem to have your ear on the ground when it comes to this box, so, can I ask (and apologies if this has been asked before) if you know if there are any plans to support Dolby Vision in the future? 

[JohnAP]

Thanks for trying Darren. I guess whatever Type B is, it'll have to remain a mystery for now.

[peskdale61]

Hi @DarrenDev - glad to hear there is still a ticket in the works for the audio issue.

Just to make a small correction - your engineer’s expectation that amps can handle DD+ 2.0 audio and upmix if needed is entirely correct.

The true problem is that the box isn’t outputting the correct metadata when the box is in “Surround” in settings. There is a piece of metadata in the DD+ signal called “Channel Mode”, which the box isn’t changing between 2.0 and 5.1 programmes. This is the metadata amps rely on to decode the signals correctly and upmix if needed.

The box is perfectly capable of outputting this metadata correctly, as it does so correctly when the user forces audio to “Stereo” in settings.

So the fix shouldn’t nessecarily require a total reintroduction of PCM, but rather adding logic to switch this “Channel Mode” correctly between 2.0 (2/0) and 5.1 (3/2 with LFE enabled).

https://developer.dolby.com/globalassets/professional/documents/dolby-metadata-guide.pdf

[gderbridge]

I am so fed up. Twice engineers haven’t turned up for appointments and now I finally have Wi-Fi my TV Box Pro won’t connect to my Smart Hub 2. So after 2 weeks of paying for a service I still can’t use my TV box. At this rate I might as well cancel the tv & just keep the Wi-Fi or cancel the whole thing & go with someone else

[zulu17]

The type B is presumably on the exterior label. It would be interesting to compare the Variant that is listed on the Device Information in the Settings submenu.

[HS6]

Hi @peskdale61 

Thank you for this further information about the BT TV Pro box Surround Sound problem.

Do you think that adding logic to switch this “Channel Mode” correctly between 2.0 (2/0) and 5.1 (3/2 with LFE enabled could be fixed with a minor firmware update?

I've started sending emails to Sagemcom about this issue in the hope of reaching the developers and getting it fixed. 

I will reference your comments in my next email. 

Regards HS6