大象传媒

Hopefully the matter I've been in contact with Danielle Nagler about and the resulting ongoing conversations between the 大象传媒 and the manufacturer of my receiver will result in a solution to the issues that this change has introduced to my viewing and more critically listening.

I do not see the point of this except where the user is using a Freeview HD IDTV.
Sure Feeview HD STB's are mandated to output 1080p25 and this is fine if the input is the same. However setting the STB to this output mode implies that it is de-interlacing the 1080i feed from other HD channels and indeed the non progressive output on 大象传媒 HD. Since I have read elsewhere that the deinterlacers in most STB's are not as sophisticated as those employed in major brand TV's the user will lose out on picture quality on othe HD channels if he sets his STB to output 1080p.

Why dd the 大象传媒 not announce and detail the nature of this trial in advance? If they did please let us know where. It seems to have caused some problems particularly with some brands of TV. Advance information would help.

Can you confirm that the 大象传媒 is still using anamorphic 1080x1440? If so do you not think that moving to 1080x1920 would be a first step?

Leadbeter: I don't know about Freeview HD STBs, but my BD player can set the output to be the same as the input signal. So if it's 576i on the DVD, 576i is what is output. I use this setting knowing that the deinterlacing in the HDTV is probably better than the BD player.

1080p25 is better for film or filmic material, and I applaud the 大象传媒 for this move to improve quality made possible by the improvement in encoder technology.

I believe that ChrisCornwall may be referring to a problem noted with a particular manufacture of HDTV which has problems at the mode change. Hope that this can be overcome somehow between the manufacturer and the 大象传媒, otherwise owners (myself included) could suffer the fate of early adopters - although there must be quite a few people out there now with these particular sets....

CJ-Epping

I agree with your observations and agree that your HDTV is probably better at de-interlacing. However unlike your BDP AFAIK most Freeview HD STB's have a fixed i or p output. Furthermore I am given to understand that a good HDTV these days will detect film type material and apply a different de-interlacing algorithm to that type of material perhaps going someway to what the 大象传媒 is trying to achieve?

Also I understand that the problems are apparent on even the current ranges from some TV manufacturers.

.... not just at the mode change, occurs during 1080p25 content as well, seems to me to be some sort of audio buffering issue as assessed from my informed ex-engineering employment position.

"A great deal of material is shot natively at 1080p25" - since 1080/50i (50Hz) has twice the temporal resolution and has a lot better, more realistic motion, wouldn't it be better to shoot a lot more material in that mode (50Hz) instead?

"The encoded bitstream can only change at each GOP boundary" - are the GOP lengths fixed or variable? If fixed, how long are the GOPs and won't that mean whenever there is a change in Hz to the encoder, the encoding will be wrong up to the size of a GOP?

Why is it that on the Humax PVR when you press Info on 大象传媒 HD it always says "1080i", even on 25Hz shot content? Also, if the Tuner/PVR is always outputting 1080/50i and not 1080/50p (eg. for if the TV does a better job of de-interlacing 1080/50i 50Hz content), does that mean that the end result on the TV will be not as high quality?

Is this change to increase the picture quality or to allow for a reduction of the bitrate but keep the quality as it was before (eg. for more channels)? How much more efficient is this new method? I thought encoding and de-interlacing of 25p material in 50i was already simple/efficient?

How many years will viewers need to wait before 1080p50 is broadcast by the 大象传媒? I know it's not part of of the original DVB T2 specs, but I thought it could/was going to be added some time later? Do any current Freeview HD tuners/PVRs support decoding of 1080p50 if it was to be broadcast? If so, do you know which ones or what percentage of Freeview HD tuners/PVRs support it?

Is it more likely that instead of some time getting 1080p50 that the next TV update will be some version of Super Hi-Vision - eg. either the 4K (2160p) version or the 7680x4320p version (at >= 50 fps) - and if so, when do you think that would be? Aren't Japan supposed to be getting it in a few years?

It will take a few years to get all the current post production "toys" to a level where Super Hi-Vision is practical for mainstream broadcasters (or whatever they are by then if broadcasting really is dead). We will also need larger living rooms to get the most of big screens. Super Hi-Vision seems incompatible with urban living!

I thought NHK were already having extended public trials of Super Hi-Vision.

Since this change, I have seen intermittent sound drops-outs on /some/ 大象传媒 HD material, although not on 大象传媒-1 HD. These drop-outs last for a tenth of a second or less, and don't appear to be correlated with either the nature of the sound or the nature of the image being sent at any particular time. It seems strange to me that only some programmes are affected, and I don't recall noticing the problem before late March. This with a Sony Bravia KDL-40EX403U, from the Black Hill transmitter in Scotland on 778MHz.

Perhaps the TV needs a firmware update?

David Taylor

This is a problem for me. I either have to set my Humax HDR Fox T2 to 1080p thus causing the stb's visibly inferior (compared to my TV) de-interlacer to be used, or I have to set my stb to 1080i thus losing the benefits of 1080p because the stb will double up the frames and then the TV will have to de-interlace it. This is compounded by reports that the HDR Fox T2 never indicates 1080p and always shows 1080i for such content, so I won't even know what I am dealing with.

I am also experiencing sound and picture drop-outs on my Sony Bravia KDL-40EX403U. The problem seemed to start in March. Before then I had no problems at all. It makes viewing pretty frustrating tbh. No firmware upgrade from Sony as yet

I have the same TV Sony KDL-37EX403 and the sound glitches are making programmes unwatchable. Sony are saying it's just the 大象传媒 doing tests but is this true? Are these tests or is this switching between 1080i and 1080p here to stay? I need a definitive answer in order for me to decide if I have a go at Sony or even reject the TV as not fit for purpose.

I think this report is a little misleading or perhaps it is because it just doesn't go into enough detail. Progressive footage can be compressed better than interlaced, but the encoder needs to be told what is progressive and what is interlaced so it can encode it as appropriate. UK TV is always 50i to my knowledge, so the encoder has always been told that and so it treats all footage as though it is interlaced. When the data is sent to our homes, it is flagged as 50i and gets decoded as that.

The H264 encoder used on Freeview HD has options where it can decide itself what footage is interlaced and what is progressive even if being told it鈥檚 all one thing, and then switches automatically to compress the footage in the best way. The encoder doesn鈥檛 know or care if the footage was actually shot in interlaced or progressive, and is still going to deliver 50i to us in our homes. Note that interlaced footage can often be treated as if it were progressive, for example a static image shown for a few seconds, or scenes with very little movement in them, so the encoder will use a more efficient method of compression on those scenes. This is why it is mentioned in the report it can change at every GOP, a GOP lasting a second or so, so the encoder will be constantly switching its compression algorithms to suit interlaced or progressive scenes.

When the encoded HD picture data reaches our decoders in our homes, the decoder is still told 鈥渉ere is a stream of 1080/50i video鈥�, the decoder then decompresses the video, and segments compressed as progressive footage are decompressed and wrapped in 50i. We get 50i as we always have. De-interlacing at the TV recreates 25p, not the decoder in this case. There is no picture degradation wrapping 25p in 50i from the decoder over HDMI.

It seems from some reports however that some TVs are reacting to the decoders decompression mode, i.e. as it swaps modes between decompressing interlaced and progressively compressed segments, but as far as I know it is wrong to be taking notice of the decoder at such a low level.

I鈥檇 be interested in some confirmation or clarification from the 大象传媒 R&D that the above is indeed what they meant.

I have a Samsung HD TV and this switches to the wrong aspect ratio on 大象传媒 HD, all other HD channels O.K.
Is this related to the 1080i/1080p switch

I have a Toshiba 40RV753B which has Freeview HD. I bought this specially for the launch of HD at the Sandy Heath transmitter. 大象传媒 HD is causing black frames, other 3 channels are perfect. Monty Don's Italian Gardens was a nightmare because of this regular but random black frames. Having read the explanations, I put it down to mixed camera sources. But then tonight there has been black frames intermittently throughout Billy Elliot, which is clearly all one source.
Can any one explain why a full length feature film should have I & P switching during it?
This problem is clearly not just effecting Sony and Samsung sets and is a disgrace!

Despite Sony issuing a firmware update on 18th April I am still experiencing audio drop outs on 大象传媒 HD. The details of the firware upgrade are pretty thin and don't mention the current problems mentioned in this forum. As far as I am concerned the situation is disgracefulm. 大象传媒 HD is unwatchable and if not fixed soon I shall be contacting Sony for a refund as I am still under garuntee.

I was so looking forward to watching Freeview 大象传媒 Hd but I find it unwatchable because of the sound dropouts caused by the dynamic switching between 10801 and 1080p.

PLEASE - 大象传媒 stop doing this until manufacturers have been able to ensure their products can deal with this.

For me, you have made 大象传媒 HD unwatchable.

I have a recent Sony TV, also and get frequent sound dropouts as the video format keeps switching between 1080p and 1080i. The picture used to zoom in and out as well on these format changes (a problem reported elsewhere by other people), although I got round that once I discovered that these TVs store their picture scaling user options separately for each video format, which therefore have to be set up twice to view the 大象传媒 HD channel.

The switches between interlaced/progressive even happen during drama/documentary programmes that are obviously originally filmed solely as 25p (e.g Doctor Who repeats on 大象传媒 HD), so the algorithm for determining whether it's interlaced or progressive doesn't seem to work very well.

I think the experiment should stop now so people with Sony TVs can watch this channel again. If it's decided by the 大象传媒 that the TVs need to handle this kind of signal, then it's only fair on viewers to pause the experiment to give Sony a chance to develop new firmware. And ideally, the progressive mode wouldn't be used again until there's a better way of working out when to use it.

That's all very well and good but what I and every Sony owner wants to know is why does this video transition affect the audio decoding of Sony TV's? You've a large number of Sony owning TV licence paying viewers who are seriously annoyed at what you have done to 大象传媒 HD

Echoing the previous post, can someone update us on this?

I contacted Sony today to be told its a transmission fault and lies with the 大象传媒, or my local transmitter.... I then told them that I knew about the issues both from the 大象传媒 and Sony forums and she then changed her tack and put me on hold.... a little while later she admitted there was an issue and that Sony and 大象传媒 were working on it and that the person "working on it" would call me back within 48hrs.

I shall give them till Wednesday and call them again with my reference number...

Meanwhile, one of the reasons I bought a new HD TV was for the F1.... which the 大象传媒 are showing on guess where..... 大象传媒 HD this Saturday!

Does the 大象传媒 and SONY have a timescale on resolving this audio dropout problem. Have Watchdog been informed. I believe the public need to be informed that 大象传媒 HD is a Beta version and there some teething problems which has an impact on Sony (Audio) and Samsung (Black Outs) TV's. I await 大象传媒's response.

The audio glitching problem on Sonys is clearly not going away. I know that there are principled arguments as to why this technical change should ultimately be implemented, but the fact is that at the present time many thousands of Freeview HD Sony owners and licence fee payers have one of their 大象传媒 channels in an unwatchable state.

It is known that Sony & the 大象传媒 are in ongoing discussions about this, but assuming Sony have committed to resolving this problem via a firmware update, as a compromise surely the change in encoding can be suspended for an agreed period until the fix can be implemented? Maybe limit the suspension to a fixed period to give Sony an incentive to get on with it?

Is the head of 大象传媒 HD arbitrating between R&D and Sony on this matter?

Hi

Yes I did email watchdog (i bet the problem would be on watchdog if it was sky or itv with the problem!)

I think though it is Sonys fault they should make Tv's that fully follow spec, Humax PVR's work on 大象传媒 HD ok so some can do it right

Is this going to sort out any sound sync issues?

"Some of you have noticed that the coding mode can change part way through what appears to be a progressively shot programme. This can happen for a variety of reasons. Even if programmes are shot in 1080p, they are usually edited as if they were interlaced. Any cross-fades, dissolves or titles will most likely be rendered in 1080i format to produce smoother movement and transitions. So the encoder must switch to interlaced mode during the effect."

What happens when they encoder detects a change from 25Hz to 50Hz part way through a GOP? Is part of the GOP encoded as 25Hz when it should be 50Hz? Won't that mean a short time whenever there is a change in the source part way through GOPs (up to whatever length GOPs are) the broadcast will have the wrong motion (since the whole GOP has to be either 25Hz or 50Hz - and not change whenever the source changes to a different Hz)? Won't this mean motion could be worse than before the encoder change?

Also, why does my Humax always seem to say the video is 1080i when viewing 大象传媒 HD?

As the new Virgin Media TiVo set top box is enabled for 1080p, can the 大象传媒 provide a response on whether the same enhanced transmission will be afforded to cable viewers please? Thanks.

"The encoder automatically detects if material is interlaced or progressive and adapts the encoding mode accordingly. Both the H.264 and DVB standards restrict changes between interlaced and progressive coding modes to video sequence boundaries, signalled by an IDR frame, so the encoder adapts its GOP structure to ensure that this constraint is met."

What GOP length(s) are used, and are GOP lengths fixed? Couldn't the GOP sizes of the encoder output be different from whatever video source is feeding the encoder?

What I meant was couldn't the source content that the encoder is re-encoding change between 25Hz and 50Hz part way through whatever number of frames are in an output GOP?

eg. if the output GOP length was 50 frames long, but the source content for frames 1-10 was 25Hz and frames 11-50 was 50Hz, would the encoder encode the whole GOP at 25Hz (progressive) giving most of the GOP the wrong motion, or encode the whole GOP at 50Hz (interlaced)?

Come on lads at R and D, 25P is a backward step. Have you not attempted to push 300P down a 10Mb/s pipe yet?

Hi Ant Miller

Please could you let us know what is happening to FreeSat. Are we seeing the development of a 2 tier system, development on FreeView ahead or beyond reach of FreeSat?

Thanks.

What is the latest state of play on the Sony sound issue, please? Freeview 大象传媒-HD can be unwatchable in its present state. Is there a resolution date?

Thanks.

Reply received from Sony today (2011 June 07)

_________________________________________________
In relation to your enquiry, I can confirm that during the current stage of digital switch overs happening across the UK, the 大象传媒 are running tests which are switching HD programmes from 1080i to 1080p. This may cause some sound drop for a brief moment but sound should then resume as normal.

Unfortunately Sony have had no confirmation on how long this will last.

Please be re-assured that there is no fault with the BRAVIA television, again this is due to the switching of the HD channels to the 1080p resolution.

I hope this information is of some assistance. Thank you for your enquiry.
_________________________________________________

It doesn't sound as if Sony are going to do anything to resolve the problem, does it, so thanks to the 大象传媒 I now have a junk TV!

David

@DonningtonDave

Your reply is way out of date. Sony are currently QA testing a fix for this and expect to issue the update at the end of June.

You should hang out at the Sony Forums to find out the latest news. The 大象传媒 are hardly going to comment upon a manufacturer's software problem.

Indeed, it seems that Sony support aren't in the picture as yet. I have asked them to check further. Perhaps you can recommend a forum where I could follow these discussions?

Thanks, David

@DonningtonDave

takes you to the end of the current discussion on this problem. Second last post on page 9 is from Sony giving their latest news.

The 3D trial is very welcome on Freeview and Freesat. Good luck with that.

What I can't understand though is that accodring to Andy Quested, the resolution 'naturally rolls off' between 1440 to 1920 pels. This should not matter whether 2D or side by side 3D is being transmitted.

I don't necessarily disagree with him for moving images inter-pixel although for static images, captions etc. This would be different.

Therefore, if you want to recapture the lead in HD and retain 1920 after the trial, (just as you Tx 1920 to Europe) I won't breathe a word to anyone I promise...

Many thanks, East_of_Newcastle.

I won't be watching side-by-side 3D images, so let's hope that manufacturers can indeed provide software updates in the meantime.

David

Sony have provided an update, which is reported to solve the problem.

Cheers,
David

I know this is an old blog but it answers a question I have and a problem with my Sony TV. I noticed that the picture on 大象传媒 HD twitches sort of zooming in and then zooming out again, only by a small amount but it's noticeable and disturbing to watch. So much so that after watching a whole programme in it I start to notice a headache appearing. Now I emailed Sony about this and eventually they came back to me with - it's the 大象传媒s fault as they're messing around with 1080i and 1080p. This blog post confirms this. However they then say that you (the 大象传媒) are at fault and they don't have to fix anything. Is this the case? Is Sony correct in their implementation? If this spreads to the other freeview HD channels then they will all be unwatchable on this set. If you can confirm to me that the spec that Sony are following for freeview HD should cope with all this then I can get back to Sony and hopefully either get them to fix the probem or replace the TV as it's not fit for purpose. Thanks

Is this blog still active ? I have noticed some broadcasts of 1080p25 material on 大象传媒1HD and on ITV1HD from the Winterhill transmitter (and presumably across the country as well). I understand that the 大象传媒 currently use 1080 x 1440 on freeview hd because that is what is used on freesat hd. Is this a limitation of freesat hd, in which case why limit the potential of freeview to match something inferior ? Also, I understand that hd on satellite delivers a higher bandwidth thus providing a better picture all other things being equal. Do ITV and C4 use 1440 or 1920 on freeview hd? Why has the data rate of the freeview hd channels been lowered from 14Mbps to an average of 8Mbps ? Finally, would it be possible now to broadcast freeview hd in full 1080p50 using a rate of 16 Mbps and would modern televisions and pvrs such as the Panasonic BW780 be able to cope with this ?

Like others on here I am noticing short drop-outs of signal on Freeview HD even though the signal strength is strong. When is this going to be addressed?

Sony EX 703 40
I'm not getting audio drop out, but I am getting the zooming as it switches between 1080p and 1080i, very annoying. What's being done to resolve this?

@tobs74

The zooming you are getting at the switch is nothing to do with the 大象传媒. It's a 'design weakness' in the Sony that it stores seperate picture settings for Progressive and Interlaced pictures. You have probably set your picture to 'Full Pixel' to eliminate overscan during a 1080i scene. However, you also need to repeat the setting procedure whilst a 1080p scene is showing to ensure Full Pixel mode is retained for both picture formats and you don't get the overscan turning on and off at the transitions.

Completely not obvious, and only something that people are going to know how to fix if they follow technical forums!

That said, the Sony firmware fixes over the past few months mean that there are no longer any sound issues.

@CJ_Epping

Thanks for the info'

Regards
Adrian

I'm hoping this blog is still going as it's the only thing I've found on the web recently relating to my issue. Since the 'turn on' of Freeview HD in my area (oxford transmitter), I have found the HD channels work on my TV(Toshiba 37RV753B), although the picture quality and sound are both great; I have been getting the blinking split second black screen intermittently on all 4 channels, which do cause quite a distrction at times. I contacted Toshiba who said there was a fault and agreed to replace the TV. I upgraded the TV to the 40" version (40RV753B) and since installing last week it is doing the same thing. I called Toshiba again, and this time they said the TV is fine but the Freeview HD signal is the problem, and mentioned about the 1080i and 1080p issue. What I would like to know; is this true? and what is being done about it. What can I do? will changing the tv again, but for a different manufacturer going to help? This has really spoilt the experience of HD for us, it was that bad we had to turn back to SD freeview to watch the Frozen Planet this week. Your advice will be much appreciated, rgds...SFX

Hello Silverfox1962

Toshiba currently has new SW which will improve this problem, can you confirm which SW version you have in your 40RV753, please select 'System Information' from the menu and confirm the SW version ? It should be something like 10.2.XX.X with the X's replaced with numbers.

WBR

Hi Toshiba Service,
thank you for your reply, my 40RV753B has SW of 10.2.63.3 if this is not the new SW can you tell me how to update it?
regards SFX

I have exactly the same problem as Silverfox1962 above and I also live in oxfordhire. I have just bought a 40' Samsung smart tv (UE40D5520RK). Could anyone give me some advice on what I should do to rectify the problem?

Hi SFX

There is a newer version which we can supply to you, just so we know exactly who you are, you recently had a 37" replaced with a 40RV753, also you E-mailed Toshiba yesterday ? We shall contact you directly with details of how to get the new SW, thank you for your feedback.

WBR

Hello Toshiba Service!

I have also recently noticed this problem on my 40RV753B SW 10.2.63.3.

Can you supply me with the update to remedy this issue?

Thanks to KE1TH & Sparky1pq from avforums.com/forums/lcd-led-lcd-tvs/1252086-toshiba-32rv753-37rv753-40rv753-owners-thread-10.html#post15736628

I expect alot of other users would like this update aswell.

Hi,

We are also having the black screen problem with our two 40RV753B models, running firmware 10.2.63.3, where can we download the firmware to fix it please ?

Hello Ed Rush

Yes, we can help with a SW update, could you please contact the Toshiba support desk on 0844 856 0730 where we can get your details, we can then work out the best method to get you the SW.

WBR

Hello Ian

Please can you do the same as Ed Rush and contact us on 0844 856 0730 ?

WBR