HD VUDU: Two Days, Two Titles, Two Different Experiences, A Quality-Deficient Result?

Following up on Wednesday’s coverage, I got tipped off via reader feedback early this morning that my earlier hunch was correct; the Bourne films (or perhaps just The Bourne Ultimatum…information on the support forums isn’t clear) is/are indeed (a) ‘trophy’ title(s) that the company encoded at a higher bitrate than the remainder of its HD library. The timing to receive this news was perfect, as Sweeney Todd became available for rent in HD late last night.

I punched ‘rent’ at 6:20AM, at 7AM (40 minutes later) my VUDU box reported the download as 28% complete, and at 7:15AM (55 minutes after the download began) the film was 37% progressive-downloaded and ready to play. Contrast this uplifting experience (which is also more than 10 minutes faster than my earlier Apple TV HD experiment) with Tuesday night’s underwhelming result; only 28% downloaded (and nowhere near ready to play) after a 90 minute delay. What’s changed?

The respective films’ runtimes don’t supply the answer. The Bourne Ultimatum is 115 minutes long, whereas Sweeney Todd is 116 minutes long, according to IMDb. And The Darjeeling Limited (which I’d previously downloaded from the iTunes Store) is even shorter, at 91 minutes.

WAN bandwidth, however, provides a clue. As I mentioned on Wednesday, I was only able to pull 2 Mbps of downstream bandwidth through my VUDU box when downloading The Bourne Ultimatum on Tuesday night. I’d suspected that VUDU had hard-limited the speed, but I was wrong; this morning, my box is measuring 2.3 Mbps download speeds (at or near the peak bandwidth potential of my DSL pipe). Again, what’s changed? For one thing, I suspect, overall Internet congestion is reduced early in the morning as compared to late in the evening. Also, with fewer VUDU boxes function-focused on playing back content early in the morning, more of them are available for peering purposes.

The final factor, as I suggested above, is a reduced Sweeney Todd encoded bitrate versus The Bourne Ultimatum (for which I’d previously calculated ~6.2 Mbps). This time, extrapolating my 28%-complete-after-40-minutes measure (and assuming the 2.3 Mbps DSL speed holds constant throughout the remainder of the download time interval), I estimate that the film will completely finish downloading 143 minutes after I approve the rental transaction. This translates to a 2.5 GByte file size and, dividing that measure by the playback time, to a 2.8 Mbps encoded audio-plus-video bitrate.

With all due respect to VUDU and to the H.264 codec I’m assuming the company is using, that’s pretty aggressive compression given the content’s HD claims. Consider:

• The Bourne Ultimatum was 6.2 Mbps.
• The Darjeeling Limited, via Apple TV, was 4.4 Mbps.
• ATSC material, admittedly encoded using the much older and less bit-efficient MPEG-2 video codec, is 19.2 Mbps.

I’ll withhold final judgment until my eyes peruse the material (and in this case I’ll definitely benchmark this ‘HD’ presentation against a red laser standard-definition DVD alternative on my high-def LCD), but I daresay I’m beginning to better understand the technical underpinnings of Gizmodo’s skepticism.

Followup: Here’s a calibration check I just thought of. Sweeney Todd in surround-audio-plus-’HD’ video, delivered by VUDU, is only 2x the bitrate of uncompressed, two-channel, 16-bit, 44.1 kHz-sampled audio-only coming off a Red Book CD. Granted, lossy compression of audio and video can produce some impressive results, but c’mon…