BBC HD Audio droput when switching from 1080p to 1080i

[drchrissmith]

Hi

Just an enquiry on what the status is of the recently introduced problem on the BBC HD channel on the EX503 (and probably all 2010 Sony TV's that can receive Freeview HD). The new BBC HD codec now allows for dynamic switching between 1080p and 1080i content which causes a short dropout in the audio stream on Sony TV's. Is this problem going to be addressed by Sony/BBC with an update as it makes BBC HD fairly unwatchable with the continuous audio dropouts.

Other than this issue very happy with the TV (aprt from not being able to slect HD channel override so BBC1/ITV etc could be set to use the HD version by default).

Thanks

Chris

[stevehicks]

I am in the same boat; just abandoned Monty Don HD for SD due to sound dropout.

Looking forward to the update.

Of course Eastenders is now sound and picture perfect on 1080i.

[copicke45]

daander75,

Was just about to say that the glitching is still happening. The BBC encoder was switching between 1080i50 & 1080p25 during Indiana Jones on the BBC HD channel this evening (which is a bit strange seeing that it is obviously movie material, and you would have thought it would stick to 1080p25), and the corresponsing sound glitches were still there.

Have to say however that I can't see any problem with the 'Full Pixel' setting when the progressive / interlaced transitions occur on my KDL-40EX703 - don't get any change to overscan in the way reported by jedininja666.

Message was edited by: copicke45

[jedininja666]

copicke45:

It's really strange, some days it was happening all the time, but then yesterday the transitions weren't making me lose Full Pixel, I was only getting the audio dropouts.

But then other days it would enlarge and shrink constantly from scene to scene. Really weird. I just hope that Sony gets this firmware out soo, because this has been going on for well over a month now, it's getting a bit ridiculous to be honest.

Message was edited by: jedininja666

[norbertmunchkin]

Hello,

I've just come across this thread, and I'm suffering from this problem on a new Sony 40EX503, and the picture popping in and out on the BBC HD channel is also making it unwatchable for me. It looks like the old valve TV I used to have in the 1980s where the picture would get bigger sometimes, but a sharp smack with your hand on the top usually fixed it, although I haven't tried that on my Sony TV yet ...

I think that there is a fault here at both ends:

- For a broadcaster to dynamically switch between video formats repeatedly during a programme is really not a good idea. 1080I and 1080P should be considered different formats, and I'm not surprised that the software/hardware in the TV might require some reconfiguration that might result in a non seamless video output, or audio mutes, particularly if the TV allows different user settings for the two formats. If the original programme really contains mixed field-based (i.e 1080I) and frame-based (1080P) material, it should all be encoded as 1080I, and the TV's de-interlacer can choose to do spot the frame-based parts of it itself for the purpose of restoring the original vertical resolution, which is what de-interlacers are designed to do

The worst case scenario appears to be happening here, where within a programme shot in 1080I, a real-time decision is being made at the encoding stage that a scene contains no movement and can therefore be encoded as 1080P, causing repeated format switches in the TV.

- But the response from Sony also implies an issue with their overscan behaviour. It's not true to say that the 1:1 full pixel mode couldn't be used on an interlaced signal - this contains information for each of the 1080 lines just as a progressive signal does - it is only the points in time when the samples were taken that is different. The process of deinterlacing a 1080I signal involves sometimes generating new samples by vertically interpolating/filtering,  where the deinterlacer has decided that the fields contain movement, but this does not imply at all that the resulting image can't still drive the 1080 lines of the panel. (An LCD broadcast monitor wouldn't do what the TVs do, otherwise parts of the picture would just not be visible).

I bought the Sony TV as I believed it was one of the few brands with the 1:1 mode that can show the 1080 lines directly on the panel without scaling (which will always make pictures a bit fuzzy), so I'm disappointed to find out that this only happens on the programmes (or parts of programmes) that are flagged as 1080P. From Sony's point of view, sharper pictures whould sell more TVs - it's as simple as that.

- Simon

[daander75]

Simon, I have the same Sony TV as you, but I have not suffered from the full pixel mode switching on the BBC HD so far.

I do suffer from the audio dropout and a slight stutter of the picture when the dynamic switching happens though.

Can you confirm you have the latest firmware version? (It was dated 18th April 11).

I am using Target Current and full pixel mode on that and other Freeview channels.

David

[norbertmunchkin]

Hi David,

I do have the latest firmware, but I think I can now see what is going on.

When I originally set the 'Full Pixel' mode, (using Target Inputs: Common), I was probably watching something flagged as 1080P, and after this, the picture was zooming in on the 1080I material, and zooming back out on the 1080P scenes, which tied up with the description from Sony that the TV couldn't show 1080I in full-pixel mode. I can now see that the 'Full Pixel' setting seems to be stored separately for the 1080I and 1080P modes - the mode you set will just be associated with whatever format is being broadcast at that time.

So I waited until 1080I was being broadcast, and set the Full Pixel mode for that as well, and the zooming problem has gone away (the short audio mute remains, though, and there may well be a short picture shutter as you describe, although to be honest, I haven't noticed that yet).

So the TV can deinterlace 1080I in Full-Pixel mode - it's just that the message from Sony implied that this wasn't possible.

- Simon

[daander75]

That's fine Simon. It is terribly confusing, you would think Target Common would have done it for both at the same time, but no. 

Also really annoying that you have to go via the Home button to get to the screen settings, rather than from the Picture options from the I button.

Let's hope that Sony can fix the other problem.

David

[StartTheCar]

Thanks for the feedback folks.  I have passed a copy of your thread onto our Engineers to see what they have to say.   I will get back to you all once I receive a reply.

Best regards
Lee

[stevehicks]

I was a little taken aback by the last posting; I thought a firmware update was being worked on. If it isn't, this problem needs to go all the way up the Sony chain of command. BBC too.

[pjbaker]

I have a 403 and noticed this problem on BBC HD just last night without understanding what it might be other than it seemed to occur on every scene change on the preview I was watching (like every second or two !).  I agree it is bad enough to makes some stuff unwatchable.

I stumbled upon this forum looking for something else entirely today ... my firmware is the latest 108 version - my tv updates its firmware automatically via the internet connection I assume.  I shall return hoping that a further update will correct the problem.  Did the latest update cause it?