More about Hulu’s 480p quality
Thanks to a work colleague, I was pointed towards more info about the improved resolution available for some content at Hulu that I mentioned previously. Turns our the 480p version is H.264, while the 360p is VP6. You think i’d have found that when i was looking into this before, yet I didn’t.
Here’s the quote from Hulu.
Video quality is very important to us. We adjust the video bitrate between 480Kbps and 700Kbps depending on your bandwidth. Leveraging the H.264 capability of the new Flash Player 9, we also now offer a portion of our content in a higher resolution 1,000Kbps stream. Videos available in this format will display with a 480p Hi Res button on the lower right-hand side of the player. If you have sufficient bandwidth and Flash Player 9, click the button to view this high resolution stream.
So the 360p content is most likely VP6 at 700kbps with a screen resolution of 480×360, while the 480p is H.264 at 1000kbps (or 1mbps) with a resolution of 640×480. So what’s that mean quality wise? Well, I decided to try a slightly better side by side than I did last time, so I chose an NBA game – pretty tough content to encode, given its a mix of high motion, wide shots, and a mix of video and graphics. I created a short movie comparing the quality of each (see below for my methodology). The screen shots you see below are scaled down examples of the side by side comparison (feel free to review the full size versions on my flickr account) or you can even see the video here. You will notice the videos don’t line up perfectly. I think iShowU was having a hard time keeping up with the frames on these captures, so they slide in and out of sync. The fast motion certainly didnt help either, but as you can see, they are close enough to evaluate.
To me, the H.264 is visibly better than the VP6 and its not just a matter of it being image artifacts. The colors look noticeably better to be, as does the overall image luminosity. All things considered, I’d much prefer to watch the 480p version than the 360p.
Methodology for Capturing and Comparing
I did a 960×540 screen capture of each video using iShowU and the Apple Intermediate Codec. I then drop both clips in Final Cut Pro, synced then up on the timeline as best I could, then cropped then to spilt the screen evenly. I then dropped a text label on each and exported at the sequence settings for review. I did my screen captures from this version, then encoded the posted movie using QuickTime Pro and the AppleTV settings from my book.
Tags: 360p, 480p, comparison, h.264, hulu, resolution, VP6
Well, for better of worse, you have found yourself in my little corner of the web.
RWVC.com is a sister-site for my book, Real World Video Compression, which was published by Peachpit. The goal of this site, much like the book, is to demystify video compression and help those looking to tackle problems they are having converting their video from one format to another.
Hi, with all the respect, it makes little sense to compare 2 codecs with such a different bitrate (resolution).
Hulu chose 480×360 for VP6 and 640×480 for h.264. In term of pixels H.264 resolution has almost double pixels than the VP6! Sure the H.264 video is better!
But at low rates VP6 is one of the best codecs out there while H.264 is better than VP6 at higher rates. That’s why at Hulu they’re using both the codecs!
emu – I agree there is a bit of a disconnect, however i’d also argue that had they compressed the vp6 content @ 640×480 as they had the h.264, then they’d had to have used quite a bit more than an additional 300kbps in order to maintain the image quality.
And I dont disagree that in its day vp6 was much better than other options out there, however H.264 for most uses these days is a better option, at least in my opinion.
I do have to disagree with your last comment though – i believe they use vp6 for the lower resolutions not because its good at low bit rates – its because its less processor intensive than h.264, making it better for older/smaller machines (also those likely to be watching the lower resolution to begin with).
[...] And that brings up the second issue, that of 3G. Hulu will have to figure out how to circumvent the stingy bandwidth restrictions imposed by carriers if they want to make 3G streaming a reality. In fact, AT&T only recently lifted their 20MB limit for downloads over their 3G network, and a theme of the Barcelona Mobile World Congress was that cellular networks, globally, are overwhelmed by the data usage of smartphones. Thus, you can deduce that carriers won’t be happy if users start downloading 7.5 MB per minute on a Hulu video (1Mbps). [...]
[...] And that brings up the second issue, that of 3G. Hulu will have to figure out how to circumvent the stingy bandwidth restrictions imposed by carriers if they want to make 3G streaming a reality. In fact, AT&T only recently lifted their 20MB limit for downloads over their 3G network, and a theme of the Barcelona Mobile World Congress was that cellular networks, globally, are overwhelmed by the data usage of smartphones. Thus, you can deduce that carriers won’t be happy if users start downloading 7.5 MB per minute on a Hulu video (1Mbps). [...]