The H2S makes self-sabotaged HDMI cameras work as they should in a progressive multicam environment
Native progressive video from HDMI cameras for live studio production? Ătomos now makes it possible!
By Allan TĂ©pper | October 29, 2012
If you previously read my first look at the Connect H2S from Ãtomos, consider this article to be a sequel. Last week I received my loaned H2S via DHL directly from Australia, and was able to test it as a bridge with a Sony HDMI camera (the NEX-FS100 NXCAM) to a TriCaster using a pure progressive session at Midtown Video in Miami! (Sessions in a TriCaster are like Projects or Sequences in a video editing program.) Ahead I’ll review why the H2S is truly Like a bridge over troubled waters to connect self-sabotaged HDMI cameras properly in a progressive multicam studio environment, and explain the results of my tests.
In this article
- Mission statement for this article
- Why most HD cameras still sabotage themselves by outputting progressive video with nasty 2:2 or 2:3 pulldown over HDMI, despite native internal (or at least Benign PsF) recording?
- The best solution to the camera manufacturer's self-sabotage
- The Connect H2S from Ãtomos
- Results of tests
- What comes in the box?
- Price and availability
In prior articles, I have covered both the challenges and solutions for getting true native progressive video from HDMI cameras that have been sabotaged by their own manufacturers via 2:2 or 2:3 pulldown on their outputs for recording to an external 4:2:2 recorder with ProRes422 or DNxHD cÃ³decs. That left pending the impossible dream of using multiple self-sabotaged HDMI cameras in true native progressive mode with a video mixer (“switcher”) that can handle native progressive 1080p video at the popular framerates of 23.976p, 24.000p, 25p, and 29.97p. HDMI>HD-SDI converter boxes have existed for years from other manufacturers, but Ãtomos seems to be the first to include the key feature of pulldown removal in such a box to undo the self-sabotage which unfortunately exists in most HDMI cameras today, together with a built-in test generator and even a flashlight (torch)!
Mission statement for this article
This article is specifically aimed at users of HD cameras with HDMI output (not SDI) who prefer to shoot, record and potentially broadcast live native progressive video for both esthetic and technical reasons, and are looking to feed an HD video mixer (“switcher”) that handles native 1080p at the popular framerates of 23.976p, 24.000p (now growing even in inexpensive cameras costing less than US$3k), 25p, 29.97p, and even 30.000p (not common but exists). This article is for people who agree with this pure progressive production, recording, and post-production philosophy, whether they came to this conclusion via my prior articles, seminars, or other sources. These people understand and agree with the many benefits of shooting pure progressive and editing pure progressive, whether the final delivery will be pure progressive on Blu-ray disk, pure progressive on DVD, pure progressive on the web or Internet TV, pure progressive on a USB memory stick, pure progressive on a 720p over-the-air TV station or network (be it at a low or medium framerate), or low to medium framerate progressive on a 1080HD over-the-air TV station or network (even if that 1080HD station or network may demand receiving its copy/signal of the video as PsF, as I have seen in some cases). If there are any pure interlaced lovers reading this (i.e. if you truly prefer to shoot, edit, and broadcast interlaced video), you can stop here, because this article isn't for you.
Why most HD cameras still sabotage themselves by outputting progressive video with nasty 2:2 or 2:3 pulldown over HDMI, despite native internal (or at least Benign PsF) recording?
As stated in my prior articles, although to my knowledge, the only camera manufacturer that has actually stated it publicly is Sony, the reason is probably the same for all of them: The HDMI camera manufacturers are extremely concerned about monitor compatibility, since not all HDMI monitors and HDTV sets can accept true progressive 1080p signals at their native framerate. Although several HDMI cameras I’ve tested can output 1080p-over-HDMI, it is not at the native framerate: It's progressive 1080p23.976 or 1080p29.97 over 1080p59.94, or it's 25p over 1080p50. I don't know why HDMI camera manufacturers don't handle this issue the way many Blu-ray players do: Many Blu-ray players offer a menu option to output native low framerate progressive 1080p over HDMI (and/or they negotiate via EDID). But (to my knowledge) only a couple of HDSLRs from Nikon actually output native low and medium framerate 1080p over HDMI. So we need to deal with the mess after the progressive signal has been "camouflaged" and “sabotaged” as interlaced 1080i over HDMI. This means that even though your camera may offer 1080p50 or 1080p59.94, we need to set the camera to output 1080i over HDMI, even though we are using the camera in a progressive mode like 23.976p, 24.000p, 25p, or 29.97p.
Although Sony went to great lengths to add progressive flags to their HDMI signal on several of the NXCAM HDMI outputs, to my knowledge, none of the current HDMI recorders, converters, or video mixers that have a pulldown removal feature is yet taking advantage of those flags to date. So far, the recorders (and now converters like the H2S) that I know are ironically solving the problem a different way. In the case of the simpler 2:2 pulldown (25p over 50i, or 29.97p over 59.94i), they simply treat the 1080i signal as PsF when instructed to do so, and then encode and record as true progressive 25p or true progressive 29.97p. In the case of the more complex 23.976p over 59.94i (2:3), they are currently analyzing the video's cadence to perform a reverse telecine.
The best solution to the camera manufacturer's self-sabotage
You could certainly deal with this issue as Malignant PsF via software using the methods I have described in the PsF missing workflow series, but those only apply to 25p, 29.97p, and the not so popular 30.000p. The process would be much more complex with 23.976p or 24.000p, and the transitions you do with your video mixer would already have transitions made in an inappropriate cadence. Without a doubt, if you own (or choose to purchase) a video mixer that’s compatible with framerates of 23.976p, 24.000p, 25p, 29.97p, or 30.000p, the best thing to do is to remove the pulldown in a single device, while you simultaneously convert to HD-SDI or 3G-SDI… and that’s what Ãtomos has finally made possible with the H2S!
Enter the Connect H2S from Ãtomos
At NAB 2012, Ãtomos announced its new line of converters to complement their 4:2:2 recorders (the Ninja–2 and the Samurai). There are two models: the S2H (SDI>HDMI) and the H2S (HDMI>SDI), which is the one I’m primarily going to cover in this article.
As stated earlier in this article with less detail, over the years, several manufacturers have offered converters from HDMI>SDI, including AJA, Blackmagic, Convergent Design (although they apparently now focus solely on recorders), and Datavideo. However, to my knowledge Ãtomos is the first to offer pulldown conversion removal built into such a converter. Ahead in this article, I’ll cover the details of my tests. In the meantime, here are the main goals of the H2S:
- Convert 23.976p-over–59.94i via HDMI into native 23.976p over SDI, and set your video mixer for that framerate. This is 2:3 pulldown removal, often called 3:2 pulldown removal.
- Convert 24.000p-over–60i via HDMI into native 24.000p over SDI, and set your video mixer for that framerate. This is 2:3 pulldown, often called 3:2 pulldown. (Caution: most cameras that state “24p” actually use 23.976p. Two notable exceptions are the Blackmagic Cinema Camera, which offers both, and some GoPro cameras after a firmware, which only offer 24.000p. I have not yet tested the HDMI output of the GoPro cameras, and the Blackmagic Cinema Camera has HD-SDI output, not HDMI.)
- Convert 25p-over–50i via into native 25p over SDI, and set your video mixer for that framerate. This is 2:2 pulldown removal.
- Convert 29.97p-over–59.94i via HDI into native 29.97p over SDI, and set your video mixer for that framerate. This is 2:2 pulldown removal.
- Convert 30.000p-over–60i via HDMI into native 30.000p over SDI, and set your video mixer for that framerate. This is 2:2 pulldown removal.(Caution: most cameras that state “30p” actually use 29.97p.)
The H2S converter abbreviates the term Pull Down Removal into the initials PDR. According to the Ãtomos User Guide (which prefers to call 2:3 pulldown as 3:2 pulldown, which is fine):
To activate the 2:2 pulldown function, press the MODE button once. The PDR LED will turn BLUE.
To activate the 3:2 pulldown function press the MODE button a second time. The PDR LED will flash GREEN, indicating it is searching for a 24p sequence to lock to.
The manual continues:
3:2 Pullldown removal must be calculated from a moving sequence of video. To aid obtaining 3:2 Pulldown lock, move the camera or wave your hand in front of it.
The User Guide also states that the PDR function de-activates itself if it receives a signal that is already native progressive, so the device will work even if your camera manufacturer offers a firmware upgrade to offer native progressive over HDMI, or if you own one of the very few cameras that already do so.
On page 2 of this article
- My tests with the Connect H2S at Midtown Video
- What comes in the box?
- Link to my rant about rounded numbers in video workflows
- Price and availability
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