1080 vs. 720

Apparently 24mpbs is the maximum data rate available for the AVCHD codec. At this data rate you get incredible images. If you intercut with the HPX170, it's extremely difficult to tell which was shot with which. What's intriguing is that you get this maximum of 24 mbps in BOTH 720p and 1080p. So immediately you can see why most people say that the sweet spot for this camera is 720p. You get all of that extra data to pour in to 1280x720. So it's case closed, right? Apparently not.

Barry Green, one of the gurus over at DVXUser, and writer of several books on the DVX and HVX cams, has been doing a lot of digging around with the HMC150 to see just what you can do with it. He thankfully surmized that AVCHD was superior to HDV, and he also assumed through his testing that 720p on this camera was indeed the way to go to the maximum bang for the buck. However one thing kept nagging at him - color sampling:

"With the HMC150's AVCHD format, the frame gets resized and then the color gets cut to 1/4 the resolution (using 4:2:0 color sampling, like HDV or XDCAM-EX or XDCAM-HD). Which means that on a 720p frame, you get 1280x720 of brightness, and 640x360 of color. Whereas with 1080p mode, youll have a 1920x1080 frame, which may only have 1440x810 worth of detail, sure, but -- the chroma sampling will be at 1/4 the res of the full frame, meaning 960x540 of chroma. Well, that's a big difference, right? 640x360 = 230,400 chroma samples, vs. 960x540 = 518,400 chroma samples, or about 2.25x as much chroma...

The question then becomes: would you gain much by shooting in 1080 mode and downconverting to 720? You wouldn't gain much of anything in terms of overall image resolution, but you'd more than double your chroma res... So, does it make a difference? Um, well, yeah."

Check out the thread for more thoughts and observations from Barry. I would think that if you transcode to ProRes you should see identical file sizes in either 720 or 1080 since the camera uses the same data rate for both, but I'm going to test this for myself and see. So assuming nobody debunks this theory, I guess I'm going to start shooting in 1080p now instead of 720p. Might as well get every bit (literally) you can out of this camera!

ATT&T U-verse

A slight departure from the purpose of this blog, but I wanted to give a mini-review of AT&T's U-verse product. We recently switched from Comcast and we were glad to do it. Price wise you’re looking at more bang for the buck - more channels in general and more of them in HD compared to Comcast at similar price points. We're also getting the full 18 mbps internet that they offer, which is substantially faster than what Comcast currently offers in Nashville. So for roughly the same price we're going from having Comcast's basic digital TV package and 6 mpbs internet to having over 200 channels and 18 mpbs net. Not bad.

Internet

Now with Comcast you get their "burst" which skews speed tests and accelerates the first few minutes of your downloads, but with U-verse we're getting consistent download speeds that are more than 3 times faster than the sustained speeds from Comcast. Now all of this will change when Comcast unveils their faster internet products (some markets are already seeing these speeds), but since I live in Nashville - and we rarely EVER get something sooner than later here - I think U-verse will remain the fastest internet offering for now. There are rumors that AT&T will double their maximum download speed sometime in the near future, but that will probably require a price increase. So for now I’m very satisfied with the speeds I have.

Negatives

There are a few negatives, namely that the HD quality seems to vary. Some channels are great, others show artifacts and strobing effects. AT&T is apparently using a different compression scheme than what Comcast uses, and that they periodically improve the feeds as the technology improves. So hopefully the HD channels that are lagging now will improve in time. Also, if Verizon FIOS is what you’re after, you’re not going to get a fully suitable replacement here with AT&T. Unless you’re in a brand new neighborhood, you’re probably only going to have fiber to within 3,000 feet or so of your house. From there it’s over traditional phone lines. The install process took 4-5 hours, including them having to run a new twisted pair line from the pole to our house. AT&T will definitely spend the full day with you, if necessary, to get their product up and running. But in the end it seems like FIOS delivers substantially faster internet to their customers. But with the costs they incur to full wire a town, it’s no wonder that FIOS is offered in limited markets.

Finally what really puts U-verse over the top for me is some of the features they offer, namely the ability to watch DVR recorded material on any box in the house, being able to watch and/or record 2 streams of HD and 2 streams of SD at the same time, the ability to schedule programs on the net, and a better looking interface. The latter is pure aesthetics, but hey it counts. U-verse’s DVR interface is no TiVo, but it’s close.

I'm a bad blogger

My apologies for the lack of posts, but as an editor by trade my free time to experiment and play with this camera can come and go. Right now it's "go". But next week I'll have some time, thankfully, and I'm looking forward to it.

I'm interested in exploring my options of HD to SD. I know I can transcode to Proress 422 and then convert via Compressor to SD, but the results seem to produce flickery results. Lines at angles become jaggy. I'll have to post an example, but what motivates me to type this is right now I'm watching the SEC Tournament via AT&T Uverse. I have an SD TV still in the office and I wanted to see if I could watch the HD channel instead of the SD one. The answer is yes, I can. It's letterboxed and in general it looks great, but it produces similar results as Compressor. Lines are jagged, lots of shimmers. My assumption is the Uverse box is doing the conversion for me and it's hardware, so I'm wondering if this is the kind of results I should expect either using software or hardware down converting options? But I swear I've used an AJA Kona card before with perfect results, but sadly it's out of my price range right now.

Cineform

A commenter posted about Cineform coming out with a Mac version of their Neo Scene app that'll convert AVCHD to either a Cineform .MOV clip or ProRes 422. I haven't used it yet, but they have a free trial download so I'm going to give this a try this week and report back my findings. I'm very interested to see the file size differences between Cineform .mov clips and ProRes.

Here's the link if you want to try it out yourself: Neo Scene.

Slow Motion via Cinema Tools

So I have a link below that shows the results of using a 60p clip in FCP and dropping it in to a
29.97 timeline and applying a 50% slow mo. I'm now giving Cinema Tools a try and the results are pretty outstanding. It's an incredibly simple process. You simply open the clip you want to conform with Cinema Tools, select Conform and it'll ask you what data rate you want to change the clip to. I simply selected 29.97 and not even a second later it was done. I'm not sure if my Mac Pro Quad 3.0 had something to do with this speed, but if it does I can only imagine an octocore would be done before you even started.

Here are the results. I'm going to get a lot of use out of these ducks. They don't require model releases.

WARNING - When you select a clip and drop it in to Cinema Tools and you conform it - it rewrites that clip! So unless that's what you want to happen, make a copy of the files you intend to conform first, then proceed with Cinema Tools.