The quest for that “smooth as butter” video from a multi-rotor has been well documented on all fpv/uav/multi-rotor forums. Most pilots looking to shoot commercial grade aerial video wind up spending significant capital on a hexa or even an octo with a high-end (= expensive) flight controller and gimbal. A good gimbal alone can run you thousands of dollars — take the newest high-end gimbal that might be at the top of the gimbal food-chain right now: the DJI Zenmuse Z15N priced at $3500 for just the gimbal alone.
While the high-end hexas/octos and gimbals like the Zenmuse are undoubtably the most reliable way to shoot commercial grade video, this article will show a way to get you close to high-end quality video footage at a fraction of the cost. To do so, we will utilize fpvmanuals’ QAV500 fpv quad — our frame that is sold for $189.99.
The footage used in this article and the post production methods applied were provided by Dave Slack. Dave is a very good pilot and has developed a viable post production process to polish up your FPV quad videos.
Any serious aerial videographer flies with a gimbal. The gimbal will steady the camera and smooth out the inevitable wobbles and corrections that come from the flight controller. However, a gimbal ads significant cost and weight. When I talk about gimbals, I am talking about high-end gimbals like those made by Photohigher, Cinestar, or DJI. In combination with a high-end FC, they make your picture super smooth and therefore add a lot of value. I would personally never bother with “little”, cheap, 2-axis gimbals for small cameras like a GoPro as they tend to degrade things more then they help.
Once you add the weight of a serious gimbal, you will have to increase your set-up to a hexa or even an octo to have enough thrust. That means that your overall weight will go up and your flight characteristics will be slowed down. You will also have a big, heavy gimbal hanging below your center of gravity, which will make your multi a lot less nimble compared to a multi that is perfectly optimized in terms of center of gravity (both horizontally and vertically). The QAV500 was designed to not use a gimbal as it is meant as an FPV craft. The cameras are mounted in a fixed position and in a way that will play back exactly what the pilot saw during his FPV “trip”. Nothing more, nothing less.
One element the QAV500 brings that an expensive gimbal will bring as well is a solid vibration isolation solution that kills video jello and video vibrations that you see in most multi-rotors and quads flying without a gimbal. A video from a quad that shows zero vibrations is a necessary starting point for getting to commercial grade quality video. On the flip side, a video picture that shows even slight or only occasional video jello or vibrations makes the video unusable for anything commercial. Video jello and true video vibrations (not FC corrections) are very difficult to get rid of in post production.
Here is an example for what we classify as “high-end”. A video shot with the DJI S800, Zenmuse Gimbal, and a Sony NEX-5. This video does not need post processing. But the rig costs in the neighborhood of $6,500. Other rigs like a Cinestar or Droidworx set-up can run closer to $8,000 to $10,000 or even more.
High quality aerial footage is typically shot with high-end DSLR cameras or cameras like a Sony NEX-5 or similar. These cameras are many times heavier than a 100g GoPro and go along with the need for a gimbal and hexa or octo multirotor configuration. For this article, we’re using a $300 GoPro in 1080p/wide to keep the cost down.
Even the best and most expensive flight controller will need to make small adjustments to your multi’s flight path, changing motor speeds to keep your craft level. There are many different FCs and people have many different preferences. For this article we are using the DJI Naza. The Naza is a very solid, easy to use, and very functional and expandable flight controller. It is often regarded as being wobbly – especially in windy conditions — and hard to tune. But as you’ll see in the demo video below, I’m sure you’ll agree that the results are more than satisfying.
The video below is flown with gain settings in the Naza of 140 on all roll, pitch, and yaw axis. The QAV500 is best trimmed with a higher gain on the roll axis as the the frame rolls easier than the elongated pitch axis, but again, for this example all values were 140. We will update this post as Dave does more flight tests and zeros in on the perfect settings. Also, if you have settings that you like on the QAV500 with the Naza, please contact us.
Good gear and well balanced props
The rest of your gear can’t suck, but does not need to break the bank to get to high video quality. For this article, the build is using fpvmanual’s FM-4008 motors. The FM-4008 are good motors, but certainly nowhere near high-end motors like Tiger Motors, AXI, Avrotos, etc. in terms of overall build quality. Occasionally, you’ll have a bearing fail on the second flight or thread-lock come loose when it’s not supposed on. But, for the sub $40 price point, these motors are ‘good enough’ to get you to stable flight and lots of pop with high speeds. For props, the QAV500 was built for 10″ props, so you are limited there. I like 10×5 Graupner E-Props as they are stiff and smooth. Another thing you must do… must… is to balance your props if you want to get to the level of quality video we’re talking about here. Even Graupner E-Props must be balanced. Many times, when I ask builders if they balanced their props, they say “no, I don’t need to, I am using Graupner E-Props”. That is not correct. Every prop needs to be carefully balanced with a good, magnetic balancer. If you disagree with this statement, you might as well save yourself some time and stop reading the rest of this article.
To flash or not to flash
While flashed ESCs do speed up the response of the ESCs, the example video will prove that you can get to smooth video without flashed ESCs. All you need are decent stock ESCs, a well tuned FC, good quality and high torque (low KV) motors and great quality, well balanced props.
With all this said, lets look at Dave’s raw, 1080p GoPro recording. Make sure you watch this in 1080p. You will see no jello or vibrations, but you do see slight FC wobble as the Naza corrects the flight path. It’s these corrections that a camera gimbal would eliminate. Dave later deals with these wobbles in post production as described below.
The key to turning your QAV500 1080p HD footage from an FPV roller-coaster ride to commercial grade video footage is a touch of post processing that removes the otherwise present FC corrections. The below PDF is the process that Dave developed and ran through on this video. Dave uses a free application called VirtualDub (VDub) to stabilize his videos and the PDF shows the screenshots and his exact settings.
The resulting video removes the slight wobbles that we saw in the previous ‘raw’ video. The application does this by zooming into the video and keeping the frame steady given the input parameters Dave has developed. This process has the drawback that the video is cropped, which means you are loosing a substantial amount of real-estate that was present in the raw footage. The video is also being zoomed in on to keep the frame size at the same HD size of 1920 x 1080. This zoom effect will cause a slight blur compared to the original video quality.
And here a finished piece including the video produced in this way:
Here is another production by Dave with lots of nice down-cam footage. This video is shot with the Sony RX100, which fits on the QAV500. The quality of the video is superior to that of GoPro2 recordings due to the substantially larger sensor.
While nothing beats a high-end hexa or octo, with a high-end FC, a high-end Gimbal, and a good quality DSLR, we think that the results of the methods described here are still respectable and might be “good enough” for your purposes. You might also apply this type of build and post processing when you are required to fly extremely fast (see example video) or through tight spaces — something that is difficult to do with a much larger and heavier high-end set up.