HD Voodoo?
More and more these days, movies and other media are being served to us for purchase or rental via online streaming or downloading. This recently got some friends and me discussing the quality of such media sources. Now, it seems you see the “1080p HD” label on just about EVERYTHING. I wouldn’t be surprised if Detroit’s next car model is the “1080p”. But what does “1080p HD” mean, really, and should it mean something else?
All “1080p” really means is that the resolution of the media is 1920×1080 pixels, and that it is progressive-scan, not interlaced, video. Labeling something as 1080p does not in any way (unfortunately) indicate the quality of that video. Although the FCC never set any guidelines on what qualifies as true high-definition video other than just resolution, I think that slapping the “HD” label on something should mean more than pixels. One should be able to expect a stunning picture when you see the “HD” label.
In theory, one could take a 480p x 720 (that’s standard DVD resolution) video and scale it to a resolution of 1080p with no interpolation, and you’d get a 1080p resolution picture with absolutely zero change in apparent picture quality over the original, but substantially larger in file size. I highly suspect that a lot of the “1080p” content we see out there these days is what some might call “pseudo-HD”, and probably barely (if at all) better than a decent DVD picture of the same material.
For example, take the video streaming site, vudu.com, and Vudu’s ads for 1080p “instant” streaming. Blu-ray discs can have a capacity of 50GB, with the movie alone taking up 30~40GB, and a bitrate anywhere from 15Mbps to 40Mbps. How can a movie that large be available “instantly” with a standard broadband (e.g. 2Mbps speed) internet connection? Answer: it can’t.
Warning: the following may seem like I’m picking on Vudu. I’m not. They offer a really cool, high-quality service. I am picking on their marketing, and maybe a bit of their technological choices though
I think a lot of people forget that there’s more to HD picture quality than resolution. Bitrate is just as, if not more important than resolution. The only way these sites are streaming 1080p instantly is with a relatively low bitrate. A low bitrate means high compression, and low picture quality, regardless of the resolution.
Think about how stunning a good Blu-ray movie is. To me, it is surprising how much better some BD (Blu-ray disc) movies are than even a good off-the-air (OTA) HD broadcast. This is not because the resolution is different (1080i/60 from an antenna is easily and losslessly converted to 1080p/24 by most decent HDTV de-interlacers) but because the bitrate for a good BD flick is often twice that of most OTA HD broadcasts, and even more than twice the bitrate of most cable and satellite HD signals.
OTA 1080i HD signals max out at around 19Mbps, with most averaging around 12~15Mbps depending on how a given station allocates their bandwidth. Vudu however, based on their system requirements, caps its instant-HD bandwidth at just 2Mbps (the minimum bandwidth one must have to use their “watch instantly” feature). That’s less bandwidth (bitrate) than virtually all DVD’s have.
The trick of course, is new more modern codecs. DVD (and OTA HDTV broadcasts) still use the now outdated MPEG-2 codec, while everyone else (cable, streaming, and satellite) have switched to MPEG-4 or similarly modern codecs (H.264, etc.) So 2Mbps gets you a lot more picture quality with H.264 than it does with an MPEG-2. Okay, but most Blu-ray discs use either VC-1 or AVC (i.e. H.264) codecs. Which brings us back to the question, how can you promise 1080p HD with 3Mbps bandwidth? Even with buffering and the newer codecs, we’re still an order of magnitude away from the 30+ Mbps rates of many Blu-ray movies.
Don’t get me wrong - Vudu definitely has a great service. But I’m skeptical about their “HD 1080p” tag and its quality. (To be fair, it’s not just Vudu, Apple is touting HD streaming now too.)
Anyway, according to Vudu’s site, the minimum bitrate necessary to “watch instantly” is 2~3Mbp. This includes their 1080p HD content. It does NOT include however, their premium quality HD content, called “HDX”. HDX is just the tag they’re using for 1080p HD videos encoded with H.264 technology at a higher bitrate. HDX movies require 2 to 3 hours of buffering time before the box will let you watch the movie. They claim “near Blu-ray quality” and “virtually artifact free”. Those words sound like they’re hedging to me. If we’re comparing to Blu-ray as a quality standard (which Vudu is doing), do the math: 2-3 hours of buffering before you can watch a HDX quality movie means that the file size is still only around 4~8GB. That’s the size of a standard DVD movie. Again the new codecs get you better picture quality for the same file size, but Blu-ray moves use these codecs and are 5 to 10 times larger in file size. To call these “near Blu-ray quality” is really stretching the truth, in my opinion.
Regardless, HDX movies are pretty good, considering they are quasi-streamed. You can order one from your work PC at 5 pm, and watch it by the time the kids are in bed and the dishes are done. That’s really cool. But is what you watch really comparable to a real Blu-ray disc experience? I really don’t think so, especially on a large screen.
Vudu’s HDX format is “recommended for 40 inch and larger HD screens” which implies that their standard “HD” videos are NOT recommended for screens larger than 40″. Why? Given the low bitrate, this is probably because they are loaded with compression artifacts like macroblocking. What I want to know then, is why do they waste bandwidth and file size making these videos 1080p resolution? The same overall picture quality could most likely be had with lower resolution, the same or higher bitrate, and smaller overall file size.
Anyway, I guess my point is: buyer beware when you see “1080p HD” plastered everywhere. Check the bitrate! What are your experiences with streaming of so-called “HD” content? What so you see as the future of streaming HD content to consumers vs. going to Blockbuster or Netflix and getting movies on a disc? Share your thoughts in the comments section below!
Kieran Coghlan
April 7th, 2009 at 6:38 pm
Not to be the first comment on my own post, but this was a timely piece of news:
http://www.reuters.com/article/ousiv/idUSTRE53568L20090406
Blockbuster has expressed concerns about its own viability to the SEC…
April 8th, 2009 at 3:01 am
As an actual owner of a Vudubx100, I can say that the difference between an HDX and HD-DVD are indistinguishable to me. The sound is in DD+, which is very good. I have not needed to wait more than 2 hours for a movie in HDX to be ready. The wife and I watched Dr. Zhivago in HD the other night and we were impressed with the picture quality on my 50′ DLP. In HDX, I watched Ironman and the detail (even film grain) was astounding! Add to it the other features that Vudu offers (Vudu labs with free Picasa, Flicker, Pandora, games, TV shows, etc) and I am a “happy camper”. Now, is it exactly like BD? No. But it is so good, that I am no longer interested in going with BD. With Vudu vault, I can store my purchases for later, so no racks full of discs that I buy, watch once and then watch them gather dust…and lament after a few years about all the $$$ sitting on that rack. Part of the appeal is the instant gratification of watching a HD movie when I want…and Vudu has HD’d over 1400 movies so far…many in HDX. HD streaming is the future…and the future is now!
April 8th, 2009 at 8:54 am
From a marketing perspective I completely understand using the terms “1080p” and “HD” on high quality video. If VUDU didn’t start touting 1080p, Apple would have and so forth. Even Netflix has gotten into the game of HD now and I believe there streamed movies are only 1 to 2 Mbps.
Because there is no standard definition of what 1080p is, like you said, it can technically be anything. I’ve compared the VUDU’s HD to that of Apple and Netflix and I feel that VUDU is indeed the highest quality. Is it true HD? Depends who you ask, but it is the best from a streamed source currently. I think I am OK with that.
April 8th, 2009 at 11:47 am
HDX touts 1080p/24…while Apple is 720p. HDX has the following features:
• Psychovisual Processing
Improves picture quality by enhancing details in dark areas of the picture, virtually removing the dark area artifacts typical of Internet movies.
• Film Grain Preservation
Improves the cinematic experience by ensuring that the displayed picture remains true to the fine optical texture of the original film.
• Statistical Variable Bitrate
Ensures optimal video quality throughout the film by allocating a higher encoding budget to high detail and high motion segments of the film, while preserving the ability to stream it over the Internet.
• Color Gradient Processing
A unique technology used to tune the picture for optimal display on modern LCD and Plasma televisions.
…all I know is it looks great, is easy to use and has a huge HD library of films (both new and older classics). With the imminent demise of Blockbuster, the internet just became the new big kid on the block. Viva la downloads!
April 8th, 2009 at 8:33 pm
Thanks for the comments, guys.
Jim M: I’ve seen the HDX demoed in store, but didn’t get a chance to see Vudu’s “standard” HD faire (i.e. those videos labeled as 1080p HD, but not “HDX”. Can you comment on the difference you see, if any?
Thanks.
April 8th, 2009 at 10:44 pm
Just a correction… I wrote:
“The same overall picture quality could most likely be had with lower resolution, the same or higher bitrate, and smaller overall file size.”
That statement is incorrect. Regardless of resolution, for a given video (i.e. a given playing time) bitrate determines filesize. Overall bitrate in KB/sec * video duration in seconds = file size in KB (give or take some for overhead).
My point in the above statement was that if a low bitrate is causing video artifacts like macroblocking, then the effective *resolution* is reduced. If that’s the case, then the file should be re-encoded with a lower resolution and the same (or even LOWER) bitrate. This would result in a greater bits/pixel ratio, which would improve overall picture quality, and reduce artifacts.
April 9th, 2009 at 8:33 am
Since the HD version costs the same as the HDX, most of my veiwing has been with HDX. However, the HD versions of the above mentioned “Dr. Zhivago” and another (perhaps not quite so classic) movie “The Fearless Vampire Killers” were both markedly better in the PQ than the SD DVD versions. Not to usurp authority from a Vudu representative, but the reason we by a HDTV is for the HD picture. Vudu offers a lot of HD/HDX content to fill in our lust for movies in a HD format. True, you don’t get the “extras” of a purchased disc-in-a-box, but for most of the people I know, we just want to see the movie on our HDTV and move on to the next one. I would recommend that people go to the Vudu homepage and view the HDX demo as they do a side by side comparison of upconverted SD and HDX….hey, if a picture is worth a thousand words, a HDX picture must be worth…well, even more than a thousand! Remember, streaming HD is still in its infancy. As good as it is now, it’ll be better in a year! You heard from me here first, folks…
April 13th, 2009 at 9:47 am
Not to make hash of a dead horse. (yuck) But if a good chunk / majority of people still can’t tell HD from SD without a A/B or side by side comparison what are the odds they will be able to tell 1080 with a good bit rate from bad?
Jim: I bet if you put the same title blu-ray in and did a simultaneous comparison with Vudu on a calibrated display you would notice a difference. But it would be small. And those that are not attuned to their systems would not even notice.
We’ve got “good enough” out there and that’s what will sell for the majority. Since it sells economics drives everyone to keep putting out lower quality. We have to rely on ourselves to keep pushing manufactures from putting out cr*p with new labels. I recall being underwhelmed at the first HD-DVD titles. They looked no better that a high quality DVD upconvert on my system - and that’s with an A/B comparison! “This is the new high res????” I thought.
Try it yourself. Get your fav Blu ray, and go download a 8Gb HD torrent of the same (you are allowed to own a backup copy so there’s no legal issues here). Have someone else hit play and then try and guess which one you are watching. 50/50 says you get it wrong.
And If you ask the Significant other in your life to watch the HD torrent rip and ask for their opinion on the PQ…. You’ll likely get a sigh and a long suffering look with a comment like “it looks fine, stop fiddling and watch the movie”
April 14th, 2009 at 7:37 am
I’d like to direct everyone’s attention to the recent news that Time Warner has been testing an ISP pricing model that caps downloads per month, and charges overage fees if you download more than your allotment in any month. This is similar to many cell phone plans. The implication of course is that companies like Vudu and Netflix will suffer (Netflix less so since they are still primarily a disc-rental business) and my prediction that downloading of hometheater media is the near future may not come to pass… not as soon as I thought anyway. This is of course assuming TW’s test markets prove successful for them, they go national with it, and other ISP’s follow suit. I certainly hope this does not happen! Here’s a link to one article on the topic:
http://news.cnet.com/8301-1035_3-10218431-94.html
Greg,
Good points. While I agree that most people wouldn’t tell the difference (or care even if they could) between Vudu’s HDX and a real blu-ray unless it was side-by-side, I think this website’s audience for the most part could tell, and does care. Personally, I’m usually the skeptic when it comes to detecting minor improvements in media quality. I’m a bang-for-buck kind of guy, and my “point of deminishing returns” is pretty low usually. However, super-high bitrate 1080p blu-ray discs make up one area of this hobby that has made me take notice. I am astounded at how much BETTER a *good* (i.e. high bit-rate) blu-ray disc looks compared to the best HD material that was available before blu-rays came out (that being off-the-air HDTV programming). This is without a/b comparison…
Also, my point in this is post was not that the “good enough” isn’t “good enough”. For most people it is. Heck, given the convenience it’s good enough for me too, most of the time. My point is that what is available to be streamed online is not true 1080pHD material, if your benchmark for such a thing is a high-quality blu-ray disc. The label “1080p HD” is being thrown about by marketing folks these days, and people need to know what they’re buying, and what they should expect. If it’s streaming, it’s most likely not as good as what you’ll see off of a blu-ray disc.