In recent years, the popularity of action cameras have skyrocketed with the success of GoPro’s offerings finding their way into hands of adventurous sportspeople, motorsport enthusiasts, skydivers, scuba divers, drone operators and even broadcasters. The breakthrough was in the compact size, good video quality and iconic fish-eye first person view footage which brings a new perspective to the viewer. Such videos have had wide exposure, and as a result, such cameras have been flying off the shelves.
Many companies have since tried to capture a slice of the market, which is still dominated by GoPro, by bringing products at lower prices. Considering that the entry model is priced at AU$300 with the top model priced at AU$750, that leaves a lot of margin to spare, but many have not met with great reception because they are merely rebranded low-quality Chinese products which fail on poor video quality, sickening rolling shutter artifacts, insufficient battery life, poor sensor and optics and limited accessory support.
Again, this is where Xiaomi comes to the fore, with a product from Xiaoyi (an ecosystem partner company whom they invest in) called the Yi Action Camera. This is a GoPro-like sports action camera with a similar size, promising the quality we desire at a price which we can afford. It claims to sport a 16MP Sony Exmor-R CMOS sensor and a 155 degree F/2.8 fish-eye lens with an Amberella A7LS processor and Bluetooth+Wi-Fi connectivity, which compares rather well with the GoPro, all at a price of around US$100.
Thanks to the generosity of the staff at Xiaomi Singapore, they have provided a Xiaoyi (Yi) action camera (white) and waterproof case (green) for testing under the terms of the review challenge. Lets see how well it performs, and whether it is a viable competitor.
Lets first start with the Yi Action Camera itself, which comes in a natural wood-coloured box with simple markings and a short-form specifications label on the rear, as is normal Xiaomi style. However, this Xiaoyi product is branded Yi rather than Mi to reflect this.
Removing the top lid, we are greeted with the camera, covered with protective plastic for shipping protection. The camera we are reviewing is white in colour, although it also comes in lime green.
You also get a battery, rated at 3.7v 1010mAh, a short flat USB A to microB charging and data cable (which is the same high quality cable that comes with Xiaomi power banks) and a Chinese leaflet. These are the standard inclusions, so it’s likely you would purchase some accessories to make the most of the camera (e.g. cases, mounts, microSD cards) and keep it safe.
A closer look at the camera shows that it sports a simple design. The front is adorned by a power button that also acts as a mode toggle, with a round LED ring to show battery status. Other than that, you have the fisheye lens, flanked by a protective ring that doesn’t quite protrude far enough to protect the tip of the lens.
The sides are adorned by a less slippery, brick-patterned texture, with the top side featuring a hole for the microphone, a shutter button, and an LED indicating the recording status.
The underside features a tripod screw mounting, more holes for a second microphone (likely) and another LED indicator that mirrors the one on the top, so you can see the recording indication from multiple angles.
Likewise, the rear of the camera has another LED indicator mirroring that of the top and bottom. Two doors are also provided, with the left door covering the microSD, microHDMI and microUSB ports, and the right door for the battery.
Neither door is captive, and the small size of the left door makes it especially easy to be lost, although the camera will still function without it. The right door for the battery also contains foam pressure strips to keep the battery tightly in contact with the contacts at the bottom.
The door itself is held by two thin plastic tangs which doesn’t seem particularly substantial, so we’ll have to see if they last. So far so good though, and if you don’t change batteries often, this might not be an issue.
Finally, along the right side of the camera is the wireless button which turns on and off the wireless connectivity. The LED above it is a blue LED which indicates the status of the connectivity.
Unlike most GoPro cameras, there is no status LCD, so it can be difficult to work out what mode the camera is in, so using the app with Wi-Fi for setup is highly recommended.
Moving onto the waterproof case, which comes in a similar box package, but larger. The case itself claims to be IP68 rated and is made of polycarbonate, glass and silicone.
As soon as we open the box, we see the constituent parts of the waterproof case – namely the main body of the case which is covered with protective plastic, the tripod base attachment and the securing screw.
Once unpacked, you also find a Chinese leaflet as well.
The case itself features a teal green flip-top clip which secures the front and back segments together. On this is the Yi branding with a slogan of “see different”, which is hard to make out on this photo. There are three buttons as well, for the three buttons of the camera, and they seemed to be made of finely milled stainless steel.
The case is hinged at the bottom, and has a thick white silicone gasket seal around the edge which fits very snugly. The main body is made of polycarbonate, which is the same stuff as CDs and bulletproof plastic shields, which should be able to take some abuse. The lens area is covered with glass, which seems to be quite dirt and fingerprint resistant for easy cleaning and best optical quality.
Laying it out, we can see the rear has a silicone pad to help apply pressure to hold the camera in place firmly.
The angle of the case is controlled by the screw and tripod adapter arrangement which has a relatively small handle. It proved slightly difficult to fit due to mechanical tolerances but kept the camera held tightly against vibration and other movement.
The feet of the tripod base was small, so while it could stand in the case fairly okay, it would not accommodate extreme tilt angles without falling over.
Testing with the scales showed that the camera weighed about 70 grams with a card and batteries, with the waterproof case weighing 84 grams.
Camera and App Features
Setting Up and Tour of the App
Getting properly started with the Xiaoyi requires a smartphone or tablet with Wi-Fi connectivity. The first step is to install the Yi Action Camera app, which can be found in the app store or by scanning the QR codes found in the support area.
When you first start the app, you are greeted with the terms and conditions to which you must agree to use the app. Then, you must connect the camera by turning it on, and then turning the Wi-Fi on, and let the app auto-scan and connect to the camera. By default, the Wi-Fi password is 1234567890. You can change the Wi-Fi password for security reasons, but most users won’t need to do this. In case you forget your password, there is a reset sequence you can do with the buttons to reset it back to defaults, which is much simpler than the firmware-reflash demanded by the GoPro.
A slight error in the tutorial instruction is the need to press and hold the button until the light turns blue and starts blinking. I found that if I holded it as instructed, the light never came on. Instead, I held the button for two seconds and then let go, and the light came on as expected.
The main interface looks as follows, with the disconnection option and settings in the top right corner. The first tab is the preview tab, which lets you see a live stream preview of what the camera is seeing (with a little delay, and at a lower quality). The next tab is for downloading images to the phone, and the final tab is for exploring some sample footage for inspiration.
The bottom area shows the present mode, battery status, shutter button and aloows you to call up the menus to change the modes and settings.
With Quick Video, the menu also offers you the possibility to apply video effects, although this option doesn’t seem to be present anymore, and isn’t something I’d anticipate would get much use.
The second panel is the download area where you can browse previously downloaded images and videos on your phone, or preview and download videos from your camera over the Wi-Fi connection. The download rate is generally 1.1-1.4MB/s in testing, which means relatively long download times.
The next tab along is discovery, which allows you to navigate through some of the stock imagery and video provided by Xiaoyi. This also includes tutorials, although it seems this area might be of little value for users who are focused on getting the shot done.
The next place we take a look at is the settings menu, where there is a long list of options which can be changed to customize the camera to your liking (e.g. turning off LEDs, buzzers, turning on Wi-Fi by default) and also to set-up different features (e.g. NTSC/PAL mode, video rotation, time stamping, automatic shut-down). There is also a lens distortion adjustment which I presume reduces the distortion by reducing the field of view, but I didn’t try it. There is definitely a lot of things which can be changed.
Because this review took a long time to compile (to get the necessary shots, do the editing), there has been an update to the app (v 2.3.0) which brings full-screen preview mode and a change in labelling from Quick Video to Short Video. It seems that the effects for Quick Video are no longer available either or are hidden. I also tested the iOS version of the app, which is available for iPhone only (but also functions correctly in compatibility mode on an iPad), which is mostly visually the same, just with no automatic Wi-Fi connection (connect to the camera manually via Settings app first) and no Quick Video mode (although most users won’t be interested in this mode anyway because it is the lowest quality mode available).
The FAQ area also provides lots of helpful information and access to an electronic version of the manual for the camera. This is provided in English, which makes up for the fact there was no English documentation within the package, although that may be due to the fact that my package was localized for Asia-Pacific region.
On the whole, the camera was relatively simple to operate once it had been set-up with the app, and after familiarizing yourself with the LED indicators, and the results are generally quite acceptable with very little intervention required. The app is simple to use, the buttons are almost intuitive, and the Wi-Fi feature means that even if you are away from a computer with a card reader, it’s still possible to transfer photos and short videos for sharing on social media from a smartphone or tablet. For faster downloading and to avoid file system limitations, recordings are automatically split at about 2Gb.
While the buzzer and LED indicators are helpful, they can get annoying, so being able to turn them off from the app is a great feature that is included but then can make the camera’s mode difficult to ascertain because of a loss or limitation in the visual feedback. This is especially made ambiguous by the camera’s slow start-up and long times needed to enable the Wi-Fi connectivity (5-10s). Even with the LEDs on, it seems that the need to conserve power and avoid LED reflections from getting into the shots cause the LEDs to be difficult to see under direct sunlight, which again, suggests that the unit is best used with Wi-Fi control.
The lack of LCD also makes for confusion, as you can tell which mode (photo or video) but you don’t know what resolution and frame rate you might be shooting at. The camera seems to take the mode which was last used, so in the case you last filmed some high-speed footage, you might be dismayed to get home to find everything for the next day was filmed in the wrong mode with no audio. As a result, setting up with the Wi-Fi is always recommended even if previewing is not absolutely necessary. Thankfully, it is easy to turn off the Wi-Fi when done to avoid excess consumption of battery.
Testing with the app also shows that preview is limited in quality due to the limited processing power and bandwidth, but even then, with my underpowered Android smartphone, after a few minutes of previewing, the preview display will fall several seconds behind real time making it frustrating to use. Similarly with photo shooting, due to no clear indication of the shutter lag, snapping a picture of something fast-moving using the preview is fraught with difficulty, and shooting blind is not that much better. A lack of manual settings on the photo mode also limits the flexibility of the camera, however, these issues are common to most cameras of this type.
The camera itself does have some frustrations, one of which is the fact that the lens protrudes with limited protection offered. It would be nice if Xiaoyi had included a dust cap with the camera so that any stray fingers or particles won’t scratch the front element. The other big niggle is the fact that the door on the ports is not captive, and can become easily lost due to its small size.
It is a good thing that the camera itself has a tripod screw mount, and its positioning under the lens makes for an ideal location to minimise parallax error in rotating panoramas/time-lapses. It also maximises compatibility with third party accessories, allowing you to use other mounts for enhanced shooting capabilities. Unfortunately, in testing, I found that the screw mount on the body was relatively short and the screw on my tripod wouldn’t fully seat, resulting in a camera that was free to spin around.
An issue which is common to all waterproof sealed cases is that you can get internal condensation as the trapped air inside has enough moisture to condense on the interior surfaces when the case is put into cooler water. This was experienced on the front glass, and was an annoyance, so it may be best to pack the camera in a relatively dry environment and check the footage as you go.
However, the waterproof case was definitely waterproof, and held several hours under this improvised container-of-water testing as well as in real-life sea conditions (as you will see later). The design of the tripod screw allows for strange angles to be accommodated to more easily get closer to the subject, and the tripod screw point is deep enough to accept the longer screws on my tripod plate.
There seems to be some slight differences from the quoted specifications online and the actual recording modes offered by the camera, so a thorough investigation was undertaken to determine all the available modes and provide more information as to the bitrates and formats recorded – information sorely missing online.
The set of frame rates available are different depending on whether you set the camera to NTSC or PAL. There are some that are common to both modes, highlighted in green. Of the modes, there are high-speed modes which do not support audio recording, and these are highlighted in purple. These modes also do not support live previewing over Wi-Fi when shooting, so in essence, you are shooting blind.
Contrary to the specifications, the top resolution is 2304 x 1296 at 30fps, rather than 1080p @ 60fps, which seems encouraging. The audio is stated as being 96khz sampling, but the actual recorded stream is 48Khz at 128Kbit/s AAC-LC stereo. The bitrates tested on 1-minute sample clips do vary fairly considerably with mode setting, with Quick video mode offering the lowest bitrate of 512kbit/s, and the 1080p @ 60fps offering the highest at 25Mbit/s with some variations (+/- 1 Mbit/s) depending on the scene being shot. There is some strangeness in that the bitrates are relatively fixed, and they don’t exactly scale with resolution, with 2k having a lower bitrate in my observations. These values were all taken with the Quality set to High, other options of Medium and Low were not explored.
These bitrates compare relatively well with phone camera footage and most standalone AVCHD style camcorders which top-out at about 24Mbit/s, but do not reach quite the levels of GoPro’s more professional devices which can reach 48Mbit/s and above in FHD modes.
As the video is all encoded by (presumably) a hardware encoder, the quality for a given bitrate also depends on how well the hardware encoder is implemented which we will look at more closely later. Looking at the GOP structure of the files shows that the hardware encoder has relatively limited processing ability with fixed GOP structures of lengths ranging from 8 to 49 frames between reference frames. The long GOPs mostly affect high frame-rate modes, and will possibly result in some variations in sharpness over time when played back in slow motion and will mean poorer scene change clarity, although most cameras with such hardware encoders will suffer similarly. The limited reference frames also reduces compression efficiency.
All video modes except quick are shot in a 16:9 (or close to) aspect ratio. Photos are taken with 4:3 aspect ratio, and quality does not appear to be selectable. The output file size suggests the compressor is a fixed rate compressor with file size that scales very closely to the number of pixels.
Battery Life and Charging
The issue of battery life always is a concern to users, and with most cameras, the battery life is always something that we desire more of. In testing, with Wi-Fi, buzzer and front LED turned off, shooting in various modes yielded me the following recording times:
- 1h 12m 59s 480p/240fps
- 1h 20m 10s 2k/30fps
- 1h 37m Time Lapse (1s)
In all, it seems the battery is good for about 70 to 100 minutes of filming continuously without a big difference in battery life and mode. Of course, with Wi-Fi turned on, as most people would probably want, the recording time does go down somewhat. That being said, it is good to know that the camera will happily have its Wi-Fi toggled off after setting up and beginning and shoot and it will still keep running, as a way to conserve the battery where preview is not required. It is rather disappointing though, that time-lapse does not allow the camera to shoot for longer to get maximum benefit from the time lapse effect.
The battery is claimed to be a Panasonic cell, but this was not verified. The recording time is consistent with the size of the cell, although as with most cameras of this size, the camera did get somewhat warm after shooting which can be detrimental to the long term lifetime of the battery.
The design of the battery is a little strange, as the terminals are on the bottom side of the battery without any finger guards or shields, which makes it vulnerable to short circuiting if carried in a pocket filled with keys or coins. As a result, if carrying loose batteries, they should be stored in a bag, or with the terminals taped over, or a transportation case to avoid any risk of damage to the batteries, sparks or fire.
In over 10-cards worth of continuous shooting, the camera did power down correctly and save files when the battery depleted, meaning lost recordings should not be a problem. Further to this, ample warning is given in the app when connected by Wi-Fi as the battery status is shown continuously and is fairly accurate.
For those wishing for longer shooting and are willing to forego any notion of water-proofing, the camera will happily shoot when tethered to a USB power bank, such as the Mi 16000mAh bank in the picture. I was able to shoot over 10 hours in that arrangement with only 1/4 to 1/2 of the power bank used.
It will also charge while shooting in that arrangement, but charging will take longer due to the power draw of the camera itself.
Measurements of the charging current profile of the camera were made with my USB shunt arrangement, which shows that the camera consumes about 700-800mA during the bulk charging phase when powered off. Charging takes just shy of 90 minutes, with the battery reaching 80% of capacity from flat by 50 minutes.
This is relatively normal charging behaviour for lithium-ion cells, so for those who wish to do multiple long shoots in a day, a separate charger and spare batteries might be advisable.
When connected by USB, the device comes up as a USB Mass Storage device so as to be able to download images from the inserted microSD card. I benchmarked the speed of this connection, and it was about 11.6MB/s which is much less than the 45MB/s the card is capable of and the 25MB/s the USB 2.0 connection is capable of, so using an external card reader is strongly advised for the fastest download speeds.
Sample Footage and Opinion
Actually trying to show the true quality of the camera’s output is actually not an easy task. As the camera shoots in a compressed format, normally, any editing will result in degradation of the output due to generational losses in compression. Uploading to video sharing sites, like YouTube for example, also results in a further generational loss and losses due to limited bitrate as they re-encode all the uploaded files. As a result, the provided sample clip illustrates some of the quality of the camera, but not the complete quality.
To try and get as close to the quality of the camera as possible, my editing workflow was designed to use ffmpeg to transcode the recorded MP4 into lossless FFV1 encoded AVIs which were edited with Virtualdub while maintaining the YUV420 colour space. Once the final edit was completed in FFV1, this was encoded using x264’s constant quality (CQ) mode at CRF=16, which is close to visually lossless, resulting in a 20Mbit/s (average) MP4 video which was uploaded to Youtube (and subsequently, destroyed by Youtube’s compression). In order to make the edits happen, all videos were transformed into 1920×1080 at 59.94fps for a common format. The 2k format was not used due to 30fps frame rate and marginal quality difference in my experience. None of the sample footage was shot at 2k.
Unfortunately, because of my hosting, providing the full quality uploaded file is not possible. In fact, it was so big that it took about 5 hours to upload on my relatively lousy ADSL2+ line. For best results, please view in Full HD, although even then, it only has 4.5Mbit/s due to Youtube’s compression.
To try to get around this, I also upscaled the video to 4k @ 59.94fps and encoded it into H.264 [email protected] CRF=16 and uploaded the resulting 4.6Gb file (over a day of uploading and processing) to YouTube in the hopes that those with enough bandwidth to watch the 1440p and 2160p streams will be able to see close to the same quality as the original 1080p, as this is the only way to get YouTube to provide higher bitrates for the same display area (rather than pixels). The alternate 4k upscaled video is here (actual encoded bitrate is 18Mbit/s), but should be taken as a secondary source if viewing at 1080p or below due to the additional scaling which can be detrimental to sharpness. YouTube may prevent you from viewing it in 4k, so you might need to use a downloader tool to download it in 4k and watch it offline.
On the whole the image quality was very acceptable for consumer purposes, with the following notes:
- Most framerates are the NTSC “tv-compatible” frame rates, namely 30fps is actually 29.97fps, 60fps is 59.94fps, etc as shown in the table earlier. The exceptions are 24fps, 48fps and PAL rates.
- In the case of rapid shifts in brightness, the automatic exposure reacts very quickly and abruptly, resulting in a flickering image which might be disconcerting to some.
- Saturation and contrast generally get worse in very bright situations, but is otherwise pleasing. Sharpness is generally quite acceptable.
- Dynamic range is quite good, but could be better when compared with some DSLRs, with both overexposure and loss of details in shadows simultaneously happening.
- Variations in sharpness and noise that occur every few seconds seem to be a result of the noise reduction and motion compensation algorithms, or the hardware H.264 encoder in use, and can be distracting especially in high frame rate videos played back in slow motion.
- Overall sharpness seems to be high, and in some cases, it was possible to see moire patterns in the encoded video.
- Audio quality seemed to be variable, with slightly low amplitude on “selfie” videos and unusually good amplitude when stuck inside a waterproof case. The stereo channels and microphone arrangement of the camera was not ascertained. The frequency response only extended to about 15khz due to the 128kbit/s AAC-LC encoder used.
- No video recording time limitations due to overheating were experienced even in full sun exposure conditions inside the sealed waterproof case, although the unit did get warm.
- Operating in freezer (-29 degrees Celsius) conditions were also no problems in a test where recording was started at room temperature, although care is needed to avoid condensation by using the sealed case. After exposure to cold, battery charging was inhibited until the battery returned to room temperature indicating adequate low temperature protection circuitry.
As I anticipate most users won’t be particularly interested in taking photos with the camera, I didn’t spend as much time testing the photo feature. However, I did take a few photos, and my observations are as follows:
- Generally good photos can be taken even in relatively dim environments, say indoor lighting, however, noise reduction becomes relatively severe. In the example above, taken underneath a canopy of bushes on an overcast day, pixel peepers will see that the branches and leaves have lost their details and turned into something like a painting due to over-noise reduction. At small sizes, this is not noticeable.
- Even in bright light, at full resolution, noise reduction artifacts and softness is apparent, but in a manner similar to point and shoot cameras and some smartphones.
- No manual mode facilities are provided, so shutter speed is not directly controllable and long exposures do not seem to be possible.
- Shutter lag was not easy to ascertain especially when shooting over Wi-Fi with preview lag meaning that capturing fast moving objects is difficult to impossible. Using the physical button is more responsive, but there isn’t feedback as to when the image is actually taken and the shutter speed involved (i.e. chances of blur).
The photo mode is hence generally “satisfactory” for point and shoot purposes, but doesn’t appear to be the primary mode.
I couldn’t help myself but try to understand what the Xiaoyi camera does when it runs its own network. My first stop was to find out its address, so I got out Fing and checked it out.
The MAC address of the camera seems to point to AMPAK Technology, likely the manufacturer of the Wi-Fi module used in the camera. A scan for services revealed that the camera exposes a DNS, HTTP and RTSP service.
Accessing the HTTP server returns a page where we can browse the contents of the SD card, download files and possibly even see the live video. Unfortunately after poking around, it seemed that it wasn’t possible to do it through this way on the smartphone.
This intrigued me, so I checked it out on a desktop computer, only to find that the live page seems to require the VLC plugin. After I had installed it, I still wasn’t able to view the stream for some reason.
I tried manually entering rtsp://192.168.42.1/live into VLC’s Open Network Stream dialogue but nothing ever happened. The MJPG page seems to keep loading an image in an endless loop but the image is never displayed.
It seems that this could be a candidate for a Wi-Fi hosted network camera in some way, but its implementation might not be as straightforward because it’s designed for use with the Yi Action Camera app. Maybe studying the behaviour of the app closely will give us the answer, but I didn’t pursue that as yet due to time constraints.
On the whole, the Yi Action Camera is a compelling package. At one-third of the price of the equivalent GoPro product, with a very similar form factor and feature set, it definitely delivers on low price. When tested, the quality seemed relatively good for a consumer camera due to the use of a quality sensor from Sony and definitely sufficient for most holidaygoers and hobbyists alike. There were some subtle defects in the visual quality from bitrate limitation and noise reduction algorithms, and limitations in dynamic range which may make the camera less preferable for acquiring broadcast-quality footage, but the quality of the footage is more than sufficient for social media sharing, and home videos. The battery life was relatively similar, and the waterproof case worked very well, standing up to the harsh conditions and handling repeated knocks without incident.
It might not be a 100% match for a GoPro when it comes to convenience, build and visual quality, but it’s definitely more than 90% of a GoPro at a third the price making it exceptionally good value for money. Those who might be concerned about accessories will find that the Yi Action Camera is starting to gain traction with helmet, hand, chest mounts available for purchase.
For users in China, they can purchase the Yi Action Camera directly from Xiaomi China for 399 Yuan (about AU$86). For users outside of China who are interested in purchasing the camera might have some luck if they’re in the US, as Yi Technology has an official store on Amazon. Users elsewhere may have difficulty with sourcing the camera, but are encouraged to seek only official approved resellers to avoid disappointment from counterfeit products.