back to article Stubborn 'won't fix' Google U-turns on Chromecast vid judder twitching-eye blunder

Google has surprised European fans of its Chromecast TV dongle by suddenly acknowledging a screw-up with the vid-streaming device, after effectively stonewalling complaints late last year. As The Register reported at the time, users were griping about an annoying video quirk with the Chromecast, which caused some European …

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mod up

mod up. There was a *fawning* piece on how brilliant Google was on NPR "2 million applicants a year".

And they can't fix the CRAP security on Android, so a toggle switch is beyond them....

And I'm a Android fanbois ;-)

P.

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I think the underlying technical issue was that Google forgot that there was more than one frame rate in use in the world.

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"Why not include a manual toggle to switch between output modes, anyway?"

Because it's not needed...well, shouldn't be. The only thing I can think of that Google is doing to make this a headache for themselves is forcefully removing headers and/or transport stream data to save storage space. What is odd though is that this data is so very small, I couldn't imagine dropping headers to save what...32K per file?

I *guess* they are filling a buffer, and then after X amount of ms, detecting how many frames should be present. This is of course possibly needed in certain situations for best guess recovery, but it's harder to do than passing header data around along with whatever the latest and greatest recovery matrix they should be using. Whatever it may be, Chromecast isn't using a transport stream of any kind, just raw x264, which *might* be for DRM purposes.

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Actually, now I think more on it. The Chromecast device using wifi, I'm surprised it couldn't work out which country it was in - and therefore the likeliest frame rate in use.

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I just cannot fathom how any self respecting engineer can assume that what holds in the USA holds every where else. Surely there must have been some discussion about SI units in "schools", possibly even the Queen Anne gallon.

I suspect that some pointy haired boss decided that it worked in the US thus it was ready to go - "If anyone notices juddering we'll just deny it until i get a new job".

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They do know the incoming frame rate though, that's how extra filler frames are being inserted into the 23.9something/24/25Hz stream so it leaves the Chromecast at 60Hz. Presumably they can't work out that the output might be better at something other than 60Hz, either by querying the TV though HDMI, looking at the Chromecast's own country setting (if there is one), or even a manual setting.

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>Actually, now I think more on it. The Chromecast device using wifi, I'm surprised it couldn't work out which country it was in - and therefore the likeliest frame rate in use.

That would give the location of the device but we're interested in the location of the source material aren't we? There are problems with NAT, VPNs and all that kind of thing.

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It's what happens when midnight hacks are sold as products

I presume that because a video can be cast mid stream, Google's point is that the header data has already been consumed. It hasn't been discarded, though, I assume or casting would get the aspect ratio (from the header) wrong too. And I doubt they throw away the Presentation Time Stamps, so the receiver knows the time between frames and could set the refresh rate accordingly. I'm afraid that whoever implemented this didn't really know enough about digital video to know what he didn't know.

That's what happens in companies that put "cool" before "correct".

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Facepalm

Frame rate & Size

Like the vast majority of US / Japan originated designs in the Past

Kluged for PAL

Graphics card TV out NTSC/PAL jumpers that didn't work

Cards that had 640 x 480 inside overscan area on NTSC but simply cropped 800 x 600 to do PAL (768 x 576 visible).

How many PAL resolution LCD panels where there ever?

Portable LCD TVs all based on half US SD resolution (240 lines) even if 800 or 1024 pixels wide.

Today's Nvidia cards were you have to create your own HDMI HD 50Hz modes and (60Hz modes included) every time the driver is upgraded it erases all trace of your custom settings.

This is no surprise at all.

I even have one DVD that is 24fps -> 3:2 pull down NTSC 30fps converted to 25 fps interlace (Most DVDs from Film sources are 480 line 24fps progressive for Region 1 with the player doing 3:2 pull down for interlace or using component to play progressive. For PAL regions the Film source is 576 lines on the DVD and the sound is corrected by 24/25ths so player simply plays the 24fps progressive source at 25fps (interlace or progressive).

It's not hard at all to do it right. You don't need a Blu Ray disk. All streaming video and DVDs also have the required metadata for HD and especially for SD.

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That's not the issue... The problem is a difference between the display frame rate of the TV and the source frame rate.

I don't usually see the issue here in the UK as my sources are usually 30 or 60 fps, and the TV can handle 60 fps.

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There's an annoying tendency for US companies to do this...

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Not directly related, but while we're on this subject...

I just recently picked up an Asus Nexus Player (Puck) Android TV Box, so as to enjoy some Netflix, and Google Play Movies on my TV... Thing is my TV must be so damned old that it doesn't even send a decent EDID Signal with.in enough time for the Nexus Player to get out of 576p. And, worse still I was unable to find any kind of Setting that would force said change to 720p or, 1080i.

Thankfully I was able to return this back to the Store for a full refund. But, really if a cheapo Chinese Box, can change Modes, why can't this One?!

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Re: Not directly related, but while we're on this subject...

EDID is nice, but if the decoder can't do it, then forcing EDID will just lock something up. Similar to how you *can* enable 30bit color in Linux with Nvidia drivers, but if the monitor can't do it the monitor could be damaged (or more likely shit crashes until your system does).

I'm sitting in a similar situation. I have a 30bit monitor so I can enable 30bit, however, the only time I really need 30bit is in Photoshop. Sadly, VMWare does not run in 30bit, so I have no way of getting to Photoshop without actually installing windows (pass). Running KDE, I've found that hardly any applications support 30bit, so 30bit anything right now isn't within my realm of "doable", at least not now.

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Why is this hard? There are, at most, a small handful of frame rates. If it's just impossible for Google engineers to figure out which one to use, the make it user-selectable from the short list of possibilities.

I guess all that Khan Academy interview filtering isn't working' out as well as hoped.

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WTF?

You mean there are places outside the USA ?

And they do things differently to us ??

Then someone learned something.

Hopefully next they will learn why we do it differently (tip 1 look at our power grid), then they could even look at the history of monitors and see that we've been here before.

Tip 2 - make the frame rate the same as the mains frequency or multiples of it.

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Re: You mean there are places outside the USA ?

A modest proposal to resolve this, from Douglas Adams:

They were now on the very boundary of the historical consciousness of their race. This was the very limit beyond which none of them had ever speculated, or even known that there was any speculation to be done.

They flew out of the cloud.

They saw the staggering jewels of the night in their infinite dust and their minds sang with fear.

"It'll have to go," the men of Krikkit said as they headed back for home.

On the way back home they sang a number of tuneful and reflective songs on the subjects of peace, justice, morality, culture, sport, family life, and the obliteration of all other life forms.

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WTF?

Re: You mean there are places outside the USA ?

who TF modded you down for quoting DA?

A nice score because in the Radio series there is a pause and he says:

"It'll have to go".

Brilliant. I've relistening in the car...

P.

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60 Hz judders too

Most film based material runs at 24fps and the standard in the US is to run that up to 60fps which doesn't fit exactly and results in judder. American TV has always had this even back in the day of NTSC since they used 3:2 pulldown to get 24fps into a 60 field display. For PAL countries, it was normal to bump 24fps up 4% to 25fps and then a 50Hz display (50 fields per second) could display that smoothly. Trouble is, if you run your device at 50Hz then 25fps will be smooth but 24fps won't. I've gone through this with my AppleTVs and ended up just sticking with 60Hz because the judder is lessened on 24fps material than it is at 50Hz and 25fps stuff will still judder but it isn't all that obnoxious. Would I prefer the ATV to switch between 50 and 60Hz appropriately, and also output 24fps which my TV can handle? Sure, my BD player does just that but it seems like we aren't going to get that from Apple or Google. At least on the ATV I can switch it to 50Hz but most of my material is actually 24fps so it makes little sense.

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Anonymous Coward

Google is going to fix something? What the hell is going on?!

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Joke

It's snowing in hell, obviously

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TV Timing

I have begun to expect that pretty much everybody designing TV standards and interfaces was too young to have ever had a class on such things when they were in school. Sound on Film (and thus adequately synchronized sound) was demoed in the 1920s. Yet, when the U.S. networks started doing digital distribution to local stations (still analog over the air, so totally not a problem in the TV itself), I started noticing lag/lead between sound and video. Sometimes barely perceptible, but sometimes bad enough to seem like a badly dubbed film shot in another language. Doesn't SMPTE deal with this?

The "smarter" digital TVs (and some Cable company shenanigans) have only made it worse, to the point that whole sentences and associated lip movement are often completely disjoint. If they haven't even been able to claw their way back to 1923, how would you expect them to deal with 2015?

Please tell me that only the U.S., with both studios and broadcasters in a race to the bottom of the barrel, has these problems, and watching, say Dr. Who on a television in the UK, over the air, doesn't have these problems.

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Re: TV Timing

The only time I get this problem with UK Freeview is when the built in DVB-T tuner in the TV is so bad that it can't actually keep up with decoding the incoming video at line-rate, and eventually slips a little out of sync until it eventually fails completely for a few seconds while throws away all it's buffers and gets a lock on the signal again. No problems whatsoever with DVB-T tuners from brand names however, or my £15 usb DVB-T tuner with Windows Media Centre (by far the best TV interface I've ever used, and the reason that my media centre PC can never migrate to windows 10)

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Anonymous Coward

Re: A/V sync

Indeed.

My 2 year old LG TV has a setting tucked away for Audio Delay - so you can tweak the audio-video sync by a few milliseconds.

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Anonymous Coward

I suspect they did know but didn't give a shit

Anyone smart enough to build one of these is smart enough to know there are various TV standards. To sell them in the EU knowing they would jitter, was a concious decision to do so - to take the money and then deny the problem was a business decision not a tech oversight.

Screw the punters and take the cash - it's the Google way.

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Bad Article Title is BAD.

"Stubborn 'won't fix' Google U-turns on Chromecast vid judder twitching-eye blunder"

I... um... what? This headline is just terribly confusing.

Sort of like the problem itself. I work at a US-based AV equipment manufacturer myself, so I get how easy it is to get US-centric on these sort of things, but not accounting for the frame rates that will be used by most of the rest of the world? Ridiculous.

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(Written by Reg staff) Silver badge

Re: Bad Article Title is BAD.

"I... um... what? This headline is just terribly confusing."

Oi, that's our business model. Confuse the crap out of the reader into clicking on it to find out wtf is gong on.

eg: Rap for rap chap in crap rap app flap

C.

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