4 July 2008
More about Hulu’s 480p quality
Posted by andybeach under: Codecs; Ramblings; Research .
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.
Leave a Reply
You must be logged in to post a comment.
