The Ins & Outs of Getting 10-Bit Output from the GH4 with the Atomos Ninja Blade
In the past few weeks, the internet has practically exploded from people sharing their opinions, and footage, from the recently released Panasonic GH4. Most of what people are sharing at this point has to do with the camera's internal 8-bit 4K recording, which is fantastically detailed, and which is undoubtedly one of the biggest selling points for the camera. However, another feature that Panasonic crammed into the GH4, and a feature that might be revolutionary for a stills/video camera at this price point, is the camera's ability to output a clean 4K 4:2:2 10-bit signal from its mini-HDMI port. At this point, there aren't any recorders that can record the 4K signal (until Atomos releases the Shogun this fall), but if you want a glorious down-sampled 10-bit HD image from your new GH4 (and why wouldn't you), you can do it with the Atomos Ninja Blade. Here's Jeremy Young from Atomos to show you how.
Depending on your desired output frequency (NTSC, PAL, or Cinema 24), the GH4 has a few quirks and workarounds in order to utilize the Atomos Ninja Blade.
The process for recording in Cinema 24 with the Ninja Blade is about as straight forward as it gets. Set your recording format to 1080p 50Mbps, enable 10-bit HDMI output, make sure the Ninja Blade is receiving the 24p signal, and you're good to go. You may be able to push the bit rate higher than the 50Mbps setting used in the video. What effect that might have on the HDMI output, I am unsure, so definitely test it for yourselves. The other thing to remember is that the GH4 won't be recording internally if you're outputting a 10-bit signal since it's unable to record at that bit depth internally. However, if you want to record an 8-bit 4:2:2 ProRes file alongside the internal h.264 files, just make sure that you're only outputting an 8-bit signal via the HDMI.
For users who are shooting for broadcast standards, however, the process for recording 10-bit PAL or NTSC externally is a bit more convoluted. Beyond the basic menu changes of switching system frequency to 50Hz or 59.94Hz, you will also have to change the recording codec to AVCHD in order to get the Ninja Blade to even recognize the signal coming from the camera. However, the problem that is then encountered is that the Ninja Blade recognizes the signal as interlaced, even if the camera is set to output a progressive signal. In 10-bit mode, this cannot be worked around with the camera or the recorder. You simply have to use your NLE or another program to de-interlace the footage or convert it to progressive.
However, if you want to record a progressive 25p or 30p signal directly into the Ninja Blade, you have to settle for an 8-bit output, which is a bit disappointing. In the video, Jeremy mentions that the folks at Atomos have made Panasonic aware of the issue, and that this is something that could very well be fixed with a future firmware update to the camera. However, in the meantime, you either have to settle for interlaced 10-bit footage (which you can covert in post) or progressive 8-bit footage.
Have you guys had the chance to record externally with the GH4 yet? What recorder did you use, and what was the workflow like? Did you run into any strange problems with the GH4's HDMI output?
[via News Shooter]