HD Audio and Video - what is it?

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After spending great wads of cash upgrading my surround sound system to enjoy the benefits of HD audio and video from blu-rays, my local blockbuster has finally gone down the pan leaving the sum total of video shops near me to....zero.

Fortunately, lovefilm has been great over the years and the (limited admittedly) supply of Blu-ray discs has kept us going through the winter evenings but the writing is obviously on the wall and without actually purchasing the damn things what are the options?

This xmas saw the introduction of one of them ipad thingy's onto the coffee table so following in the footsteps of all the other sheep, I bought the accompanying apple TV box last month, changed to Virgin BB and joined Netflix. All good so far, faster unlimited broadband is great for spotify, last fm etc. and there's enough on Netflix to keep us amused for the next 6 months but beyond that I really don't know. Most of the stuff on there is quite old so hopefully they will continue to add to the content. What I wasn't prepared for though was the cost of iTunes; £4.49 to watch a movie and some old tv series at £32 a pop?? F*ck me, what a rip off!

But, the thing that puzzles me though is i've always assumed that the Blu-ray disc is king ie you are getting the current highest possible definition in terms of audio and video (I don't know how you define that level of resolution..i'll explain later) Taking the example of movies for the moment, when you download a recent release at supposedly 'HD' what are you actually getting? When I phoned Netflix, lovefilm et al, their answer was 1080p. But, does this actually equate to the equivalent resolution offered by BR? Is 1080p the highest you can go as this is the setting on the telly and therefore the limiting factor?

When I asked about the audio output of their streaming, I was mostly met with silence. Firstly, how do you define the level of HD audio offered by BR? and then how does this compare against the level offered by iTunes whilst streaming a movie? Are you getting the full monty when you cough up the £4.49? The reason im sceptical is the average size of Blu-ray can range from around 15gb to 40gb ( eg. happy feet). Those are huge files, so are you really streaming that much data whilst watching a movie? If yes, then £4.49 is almost justifiable, but if youre actually watching a compressed version (albeit at 1080p video) then to me, it makes it even more of a rip off and a pointless exercise investing in all this surround sound gear.

The other alternative is streaming to the ipad and mirroring onto the AV system (which would give access to Lovefilm streaming via an app) but does anybody know if this is limiting the resolution of the video or audio even further by putting the ipad in the path of router:appleTV?

 

browellm

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Firstly, re video, I'd be flabbergasted if Netflix et al are streaming 1080p. It's more likely to be 720p or maybe 1080i - happy to be shown otherwise, but I can't believe the bandwidth is there to support 1080p streaming.

Their audio from a streamed film will be Dolby Digital 5.1 (DD5.1).

Blu-Ray releases are usually (but not always for some older titles) DTS-MA or Dolby TrueHD (see Wikipedia). These are uncompressed lossless 7.1 formats

 

Jelly Tussle

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but if youre actually watching a compressed version (albeit at 1080p video) then to me, it makes it even more of a rip off and a pointless exercise investing in all this surround sound gear.
I think you've answered your own question.

There's 1080p and then there's 1080p.

If you're watching compressed 1080p (which you are when watching streamed video) the picture quality is going to be worse than 1080p off Blu-ray. Blu-ray has the bandwidth/bit rate to leave the image and sound unmolested.

At the moment, with streaming, you are paying for convenience not quality or choice.

 

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There's 1080p and then there's 1080p.
Hmmm, are you saying that the video is streamed at say, 720 for example, then the Apple tv (or any other device) scales the resolution upto 1080p for its output, but in reality its not really 1080p?

At the moment, with streaming, you are paying for convenience not quality or choice.
This is whats pissing me off. Just like the MP3 saga, more of 'that'll do' forced upon us.

 

Jelly Tussle

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Hmmm, are you saying that the video is streamed at say, 720 for example, then the Apple tv (or any other device) scales the resolution upto 1080p for its output, but in reality its not really 1080p?
No. I'm saying that anything that is compressed is more likely to show artefacts; especially during scenes of rapid motion / action. So even though the resolution may be 1080p the picture quality may not be what you would expect from a 1080p Blu-ray.

I have no idea whether the resolution is lowered and then upscaled or not by Apple TV or similar devices. Though I'm sure other folk here can tell you. I suspect that streaming at lower resolutions and applying less compression would be beneficial to picture quality.

This is whats pissing me off. Just like the MP3 saga, more of 'that'll do' forced upon us.
Indeed.

Currently I rent discs off Lovefilm; I don't stream. When/if quality and choice improve I might then reconsider.

 

AmDismal

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No. I'm saying that anything that is compressed is more likely to show artefacts; especially during scenes of rapid motion / action. So even though the resolution may be 1080p the picture quality may not be what you would expect from a 1080p Blu-ray.
Exactly. This issue is just like MP3 bitrate versus sampling rate in audio. The sampling rate might be 44.1kHz in all cases, but the bitrate can be 96kbps (poor quality) or 320kbps (near perfect). In video, resolution is equivalent to sample rate - it's important, but not nearly as important as the bitrate.

I imagine that Netflix and the like need to limit their bitrate to fit in with broadband at 8Mbps, as most people still have figures down at this kind of level. It will stream video, and do it fairly well, but it's much lower bandwidth than BD - it's probably lower than DVD, which is about 6MBps.

 

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Ok, I think im getting it. In order to evaluate the quality of a supposedly HD download, it would have to be 1080p AND have a minimum bitrate that may be close to BR. Oh, and have Dolby TrueHD as well. Not looking good is it? Be interesting to send iTunes and lovefilm an email to clarify but that £4.49 is looking more and more of a ripoff.

Out of interest, is wireless broadband actually capable of supporting such large data streaming?

 

browellm

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Ok, I think im getting it. In order to evaluate the quality of a supposedly HD download, it would have to be 1080p AND have a minimum bitrate that may be close to BR. Oh, and have Dolby TrueHD as well. Not looking good is it? Be interesting to send iTunes and lovefilm an email to clarify but that £4.49 is looking more and more of a ripoff.Out of interest, is wireless broadband actually capable of supporting such large data streaming?
It can be, depends where you live, what broadband provider you have, what your real download speed is, how contended your service is etc.

If set up correctly your wifi connection con stream uncompressed Blu-Ray, but it needs to be a great connection and set up well.

 

drummerjohn

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It's down to the bitrate with regard to quality. You can encode anything into 1080p down to silly low bitrates ie 2mbps. The quality is awful. The content on Blurays is much higher and as stated can hit 40mbps if required.

I couldn't watch any of the streaming content on my 6ft screen as it would look terrible. Which is why I hire Bluray from Lovefilm and Blockbuster online and my local video shop. You will not get anywhere near BR quality using streaming.

 

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It can be, depends where you live, what broadband provider you have, what your real download speed is, how contended your service is etc.If set up correctly your wifi connection con stream uncompressed Blu-Ray, but it needs to be a great connection and set up well.
Well, its virgin with a tested download speed of 62bps and the router is about 15ft from the Apple TV. Its a bit of an irrelevant question really considering the discussion so far but I was wondering what the bitrate/resolution etc. of the purchased films were from iTunes? are they identical to the on demand streamed versions? The only real reason im asking is a big dedicated NAS is next in line to satisfy my gadget fetish ie somewhere to store HD films. This does raise other issues, the first of which is how to (legally?) get the movies on the HDD in the first place.

 

browellm

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Well, its virgin with a tested download speed of 62bps and the router is about 15ft from the Apple TV. Its a bit of an irrelevant question really considering the discussion so far but I was wondering what the bitrate/resolution etc. of the purchased films were from iTunes? are they identical to the on demand streamed versions? The only real reason im asking is a big dedicated NAS is next in line to satisfy my gadget fetish ie somewhere to store HD films. This raises other issues, the first of which is how to (legally?) get the movies on the HDD in the first place.
It's two separate discussions really. Currently, there isn't a commercially available remote streaming service that approach the bandwidth of Blu-Ray, and I doubt there will be in the next 10 years.

Streaming Blu-Ray locally (i.e. files off your NAS) is possible and it's what I do, currently via a Boxee under the TV. There are 3 options:

1. Download Blu-Rays via torrents or Usenet on to your NAS - Illegal

2. Rip Blu-Rays that you rent from Lovefilm - Illegal

3. Rip Blu-Rays that you already own - Technically in breach of current UK copyright laws, but like ripping your own music, you'll never be prosecuted for it.

 

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Yeah, youre right about the two discussions but considering the answers that have already been written, I'm beginning to think this whole apple TV thing was a complete waste of time and effort and was starting to look at alternatives. (Even the wireless connection on my Oppo 93 is utterly useless for the UK) Depressing really, considering the hype this stuff receives.

 

browellm

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For the enthusiast, there is surprisingly little in the way of appliances on the market that will actually stream uncompressed Blu-Ray and crucially DTS-MA/Dolby TrueHD. That's one of the reasons people go for self-build HTPCs.

Apple TV is about as locked in as it gets, but then that's Apple.

 

Mr_Sukebe

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OP, I believe that you already have the solution, i.e. rent BDs from Lovefilm. Very cheap way to watch a lot of movies on BD. Personally I do that, and fill in the days without a BD disk with streamed films that are often only available on DVD or TV shows, where the loss of quality is less important.

 

Arfa

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The best way to grasp the difference between higher resolution of video (720p, 1080p, 4K etc) and different bitrates, is to take a good photo you have off your digital camera and load it up in your favourite image editor.

To begin with, your photo will be huge (if you've got a decent high mega pixel camera). It is very high resolution, in our analogy, comparable to the 4K film cameras films are shot with these days. Here's my random pic of a cute spider (however I've lowered the resolution right down to fit nice on webpage).

orig.jpg


Next resize the image, down to so-wide x 1080 high. Now save it as a jpg, but reduce the quality setting to about 80%. Essentially what happens when your film is transferred to bluray, the resolution has been lowered and it's bee compressed a bit more. Notice, there's less pixels, less detail and will look worse when scaled up (like you would do one huge tv/cinema screen). You may also just notice some blocky artefacts from the increased compression. Again see below (albeit smaller than 1080p for sake of fitting nice on webpage).

1080p-bluray.jpg


Next, save it again, but reduce the jpeg compression to say 30%. This is basically what you get when you stream films over net. The image will take up much less disk space, but still retain the same resolution, thus it's still 1080p. However the compression really kills the picture quality. See below, same res as above, just compressed more, much lower bitrate.

1080p-streamed.jpg


Now this is where it can get interesting. Lets reduce the resolution some more, down to 720 high, then save the picture with a jpg quality level that will give us the same final file size as above. i.e. the exact same bitrate. In the example below, this 73% quality. Notice how the image is obviously smaller, but there are far less artefacts.

720p-streamed.jpg


 
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