Vudu Pulls The Trigger On HD

Dave Zatz —  February 6, 2008

Last week, Vudu (now available for $295) rolled out system software 1.2 in conjunction with HD movie rentals. For the instant playback touted by Vudu, you’ll need about 4Mbps download throughput. Unfortunately, the bedroom segment of my LAN is experiencing some sort of bottleneck. According to a Vudu engineer who pulled my logs, my session was capping out at 2.6Mbps – resulting in frequent buffering pauses during The Italian Job. (For comparison, my laptop reports about 17Mbps wirelessly to router via Speedtest.net.)

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I was pleased with the picture quality and, if memory serves, find it comparable to the Xbox 360 download service. However, Gizmodo really took one for the team by watching Transformers three times (the horror!) to conduct a brief picture quality analysis (above). I can’t say I’m surprised with their findings – while Vudu offers 1080 resolution , the compression needed to squeeze that content into 4Mbps down won’t compare to a Blu-ray or HD DVD offering… Nor should it.

Services like Vudu are about providing instant gratification and given the broadband speeds across the US, this situation will not improve in the near future. Lately, I’ve been using the phrase “higher def” to refer to this sort of content – it may technically be “high def” resolution if we’re counting pixels, but no one would call it picture-perfect. Though it’s certainly a step up from standard definition.

Back to Vudu… New release HD rentals run $5.99, while new release SD rentals are $3.99. Which is comparable to the Xbox 360 ($6) and the delayed Apple TV update ($5). Of course, all these guys face the toughest competition from cable-co VOD/PPV, not each other.

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28 responses to Vudu Pulls The Trigger On HD

  1. As an aside, the top photo was beamed straight to Flickr from my camera via Eye-Fi. Sweet!

  2. Hmm. Maybe I’ll have to update my chart for Vudu to give them a red for a/v quality. I generally have been expecting the “HD” quality of most of these services to be subpar, but I gave Vudu a good rating because of all the good things I heard about their SD picture. I was hoping he HD version would really be dramatically better, not necessarily on par with HDDVD or Blu-Ray (that’s an unreasonable expectation at this point), but better than this.

    The bottom line for me really is that I want it all, I’m willing to pay a lot to get it, but I’m not willing to pay very much at all for partial solutions. Convenience (which download services offer) is very important to me, but so is quality (and everything else I listed in my chart). I keep hoping the next new offering will really blow me away, but this ain’t it…

  3. Thanks for the review, Dave. There’s been a lot of discussion as of late about Vudu’s HD quality level. Does it compare with or equal that of HD-DVD or BluRay? Does Vudu claim as much? The answer is flat out no. The Vudu will deliver HD content at Broadcast HD quality levels. It will not equal the quality you see in BluRay or HD-DVD – at least not at this point. Still, it’s amazing what their engineering team has done to get a really amazing looking image to fit into 4 Mb/sec of bandwidth. It’s truly impressive.

    Some of the customers out there have done some of their own comparison tests of HD content between XBox 360 HD content and Vudu. Below are some links to some photos comparing the two. You can clearly see that the XBox images have more pixelation than the Vudu images. Thanks to Aaronwt for these images!

    Radar image from the SD version of Transformers on Vudu.

    Same shot from the HD version on Vudu.


    Same shot from the XBox HD version.

    This shot features a bright flash of light. It is the Vudu HD version.

    Same shot as above here, but from XBox HD. Notice the pixelation.

  4. When clicking on the links to my flickr account these photos show up smallish w/no discernible detail. I can re-link from a better site if need be…

  5. If it’s really broadcast HD quality, I’d be quite satisfied with that. That’s not *that* much worse than HD DVD/Blu-Ray, and WAY better than SD DVD. The reports (and screenshots) I’ve seen so far have suggested that the compression is quite a bit higher (and thus the quality noticeably lower) than broadcast HD, but I’d love to be wrong about that…

  6. Jon, Thanks for the info and pics. I redirected the links to your larger Flickr versions.

  7. There’s a discussion thread on Vudu’s forums that talks about Giz’s mini-review — http://forum.vudu.com/showthread.php?t=2464&page=7. No one else could substantiate Giz’s findings and we suspect that Giz’s settings weren’t correct.

    LIke JonO posted, some very discerning people compared HD quality of Vudu to other sources and it’s generally agreed that HD quality is better than Xbox 360 (especially when it comes to macroblocking) but not as good as HD-DVD/Blu-Ray.

    Yesterday, one of the moderators posted Vudu’s official position on quality:
    “Official position from Vudu on HD quality:

    The HD quality of the Vudu player is considered at this point to be “broadcast quality.” This means that it is as good as broadcast HD and similar formats. The HD quality is not considered to be as good as HD-DVD or Blue-Ray and we don’t want anyone to be misled otherwise.

    The quality of Vudu’s HD content is still evolving and as such will hopefully continue to improve as time goes on.”

  8. Hm, maybe I’ll take a stab at comparing Vudu SD to HD. Though I think Vudu only outputs HD via HDMI, so recording form component isn’t an option…? With my camera and photographic skills, you couldn’t trust my pics (and suggest you take others with a grain of salt). And as I’ve learned over the years, a single frame doesn’t tell the whole story anyway – for the most part we’re going to have to rely on subjective descriptions, as Gizmodo and forum member aaronwt provided (better than SD, not as good as optical disc HD). Having said all that, maybe I’ll take some pics anyway. ;)

  9. Dave, you are correct — Vudu outputs HD only via HDMI (probably due to restrictions by content providers). I don’t have AppleTV, but from what I read it’s not 100% certain that they’ll allow HD rentals over component either.

    Anyway, I look forward to the pictures. Just let us know which output settings you used (720p, 1080i, 1080p/24). One thing about Vudu is it only supports 1080p/24 and not 1080p/60.

  10. I’m outputting 1080i from Vudu, though I can’t compare to HD DVD anymore since my unit sold on ebay.

  11. Ooo, really? I didn’t realize Vudu can’t do 1080p/60. Bummer for those of us with 1080p TVs that don’t support /24…

  12. Yes, but a 1080p/60 will convert a 1080i/30 signal with no loss in quality. They are basically the same thing if you think about it. It just deinterlaces the frames.

  13. Don’t know about live HD broadcasts, but cable company VOD is typically ~15Mbps using MPEG-2 video. Presumably Vudu is using h.264, and with current encoder capabilities it is broadly assumed there should be a 2X improvement, so something around 7.5Mbps would be equivalent to North American cable VOD. If Vudu is using 4Mbps, they’re not comparable.

    Also the macroblocking in JonO’s “bright flash” XBox HD image sure looks like MPEG-2 to me. Usually h.264 does much better at not showing this sort of step-function/blocking. Course they’re presumably using VC-1 (I assume) not h.264, but I would have expected them to be similar. Huh.

    Personally, I’d rather have options. If SD looks good at 2Mbps, and starts immediately, great. Why not run HD at 6 or 7Mbps and if it means I can’t watch it until the next day, oh well? I’d rather there were more difference…

    Dave, agreed on the still frame thing. It really isn’t fare to compare still images. Really crappy still images can look great when they’re flipping by. You need to compare the video, not the stills.

    Others, (most of) the movies they are renting are SHOT in 24p, i.e. FILM. Or at least most of them are. So there would be no benefit to encoding intermediate frames. If you’re trying to reproduce what you see in a movie theatre, 24p reproduction of 24p content is fine.

  14. Glenn, you are forgetting that Vudu’s HD content is encoded in 1080p/24 unlike broadcast content which, I presume, is in NTSC’s 60 Hz. So unless I am missing something that would mean that Vudu has over 4 times the advantage, so 4 Mbps H.264 (in 24 Hz) is comparable to 15 Mbps MPEG2 (in 60 Hz).

  15. The idea of being able to wait longer for better quality in one that people have suggested, but it makes for a problem. Part of the way Vudu works is that the first 30 seconds or so (the head) of a movie is stored on your box. If you start to have really huge movies it for one will take up more and more space on the box, but in addition since the “Super HD” and “Normal HD” movies would be encoded differently, you’d need different files for each. And since Vudu works in a P2P arrangement, the peering requirements for those few people who want the “SuperHD” would be huge.

    The HD quality between Vudu and HD VOD from cable is very, very similar. And the selection is greater as well. Additionally, going from MPEG-2 to MPEG-4 saves about 50% of the space. Going to H.264 which Vudu uses is even more efficient.

  16. And yes, Ivan is correct. All Vudu content is sent over the pipe in 1080p/24. Fewer frames per second = lower bit rate needed.

  17. But broadcast is 1080i/60, not 1080p/60. So it’s 60 *fields* per second, not 60 frames.

  18. But Sean look at it this way. 1080i is actually two sets of 540p frames at 60 frames per second. So, to put it more accurately, 1080i going to be 1920 x 1080 at 30 frames per second.

    Calculate things out. In the most rudimentary of manner, assume each pixel is 1 bit (it’s actually more than that since the pixels have color and intensity of each color and not just on or off – but it scales anyhow). Therefore for 1 frame we have:

    1920 x 1080 = 2.0736 Mb.
    Multiply this time 30 frames per second:
    62.208 Mb/sec

    Now, a 1080p/24 signal is going to have the same number of pixels per frame and since each pixel in our example is 1 bit, then we still have 2.0736 Mb per frame.

    Now multiply this by 24 and we get 49.7664 Mb/sec.

    So by using a frame rate of 24 fps, we have a raw data rate that is 12.4416 Mb/sec less.

    Now, as I said, the pixels could be considered at minimum to be 3 bits each (red, green, blue). But it’s more than that as well since there’s levels of intensity, etc. So the actual raw bit rate is quite high. But that doesn’t matter as it’s just a scaling factor. The end result is still the same in that a 24 fps frame rate will require a lower data rate than a 30 fps frame rate.

    Additionally, cable VOD may or may not be broadcast frame rates. They could send 1080p/60 data down the pipe but I doubt it since I don’t think there are many 1080p/60 cable boxes. Additionally, the cable company could use 720p/60 content as it is also a broadcast standard but 1080p/24 still has a lower raw data rate than 720p/60.

    So you can’t just compare compression formats. :)

  19. Sorry if I wasn’t clear Jon — I don’t disagree with that at all! I was just pointing out that it’s not actually likely to be “over 4 times the advantage” as Ivan claimed when he pointed out the p24 vs p60 difference. Using the simplified assumption that Vudu is getting 2x the compression ratio that broadcast is (from Glenn’s post above), it’s more like 2.5 times.

    But, as you said, you can’t just compare them this simply, so this is probably kind of pointless ;)

  20. JonO,

    There’s basically no broadcast content at 1080p, so lets forget about that. There’s 720p and 1080i. You want to talk 1080i, okay. That’s 60 fields per second, or 30 frames per second.

    Sure Vudu is doing 24fps. And you cable VOD is doing 30fps. Well actually is 29.97fps but lets ignore that.

    How many more bits does it take to encode 30fps than 24fps? Well in MPEG-2, which is what cable VOD uses, it takes exactly NONE.

    NONE? Actually yes. There is a field in the PIC header that says whether to repeat the first field of the frame or not. In the encoder when they detect that the original is 24fps they engage 3:2 pulldown. What that means is that the video is encoded so that it plays out as:

    TBT BT BTB TB …

    (where T is the top field, B is the bottom field, and the words are a single frame, with the first field sometimes repeated).

    Which uprates the 24fps content to 30fps. So all they have to do is set the RFF bit in the MPEG-2 header for each frame to achieve this. And they do that for every other frame.

    So anyway, you CAN directly compare bit rates basically.

    Now in h.264 you don’t have the TFF/RFF bits, but you can do a field repeat in only a small number of bits, so its not that different.

  21. FYI Vudu is using MPEG-4, though their PR/Marketing lead was a bit vague when I pressed him for details saying something about encoding using “other twists.”

  22. Well, h.264 is MPEG-4 Part 10, and a lot of times that is what people mean when they say MPEG-4. Could be they mean MPEG-4 ASP/SP, but that is generally thought of as being less efficient, so I suspect not… If they’re really using the full-on MPEG-4 I’d be very suprised…

  23. Vudu is using H.264. That’s been confirmed multiple times. Interesting info on the 3:2 pulldown with MPEG-2 – thanks Glenn…

  24. Jon is correct. Vudu is not hiding the fact that they use H.264 although which profile they use and exact encoding settings would be proprietary information from what I understand.

    Also, another thing to note is that Vudu gets source material from content providers and then does its own encoding. So they don’t necessarily re-compress DVD/Blu-Ray/HD-DVD material.

    As for the “twists”, I assume it has to do with optimizing content for streaming and for P2P delivery/distribution. From what I understand high-def media is often encoded at variable bit rates (higher rates for more detail-heavy scenes), but Vudu can’t afford thebitrate to jump all over the place as they have a 4 Mbps ceiling.

  25. Vudu does use a variable bit rate though in their encoding scheme. The exact encoding/compression scheme is indeed proprietary. It is also in the process of evolving.

    In terms of source material, Vudu does NOT rip source material from BR or HD-DVD or even standard DVDs. That would not be legal. Vudu gets source material direct from the studios. If the source material from the studio is poor (as some older movies are), then that will be reflected in the Vudu movie image. There’s a number of older movies that have bad source materials that have not been well maintained. This also explains why not every title is in DD5.1. If the studio provides a DD5.1 audio track, then the Vudu will have DD5.1 available. If a DD5.1 track is not provided, then the movie is delivered in stereo.

  26. Just out of curiosity, do you know how the studios provide the material? Do they send a hard drive? Do they send DVDs (distinct from the retail DVDs)? Transfer digital files directly? Mail printouts of each frame to be scanned by hand and glued back together? Ok, maybe that last one isn’t so practical…

  27. I have asked how the source is obtained. I have not been told. I wish I knew as well! :)

  28. >>I have asked how the source is obtained. I have not been told. I wish I knew as well!

    Right, that’s why I didn’t rule out that sometimes they may use same source file as the DVD/BR/HD-DVD (not likely to be retail disk due to copy protection). I was actually trying to emphasize the point that Jon made more eloquently.