While some so-called 4K Blu-ray players only up-convert the video to 4K, the Sony 4K Blu-ray Player X-800 is a true 4K Ultra HD Blu-ray player. Not only is the 4K video performance impressive, but this player is also a universal disc player and a hi-res audio player.
The Build
Sony 4K Blu-ray Player
The build quality is truly high-end. The 17 x 2 1/4 x 10 3/4 in (430 x 54 x 270 mm) device is made of solid metal. So not surprisingly, at 8 lb 7 oz (3.8 kg), it is heavier than most DVD players. Sony also offers a unique frame-and-beam chassis to eliminate vibrations as well as provide electrical shielding. There is no screen. There is not even a play button. Again, this helps to eliminate vibrations.

Sony 4K Blu-ray Player

Courtesy of Sony

There is one simple, tiny LED light above the 4K HDR and Hi-Res Audio badges. A tethered cover protects the front-facing USB 2.0 port. On the rear are two HDMI outputs. There is also a LAN port and a single digital audio coax output. There are no analogue outputs which is probably okay in this instance. The assumption is that you will be attaching this to your 4K television which has an HDMI port.
Sony 4K Blu-ray Player
Interface and Basic Usability
The Sony X800 has solid usability. The tile-based interface is simple and quite functional. You can move the tiles around which cannot be done in some other Blu-ray players like the Samsung 4K Blu-ray player.
Sony 4K Blu-ray Player
Once online either by Ethernet or by the wireless connection with dual-band MIMO technology, the device immediately identifies NAS devices and media servers.
4K streaming services like Netflix, YouTube, and Amazon are supported. So are most other common streaming services. The notable exception is HBO Now, but that may well be added later.
The X800 has Bluetooth 4.1 and supports 3D video. It also supports Miracast Screen Mirroring.
The Sony UBP-X800 supports more audio and video formats than any other player I’ve seen. For example, audio formats include AAC (.AAC, .mka), AIFF (.aiff, .aif), ALAC (.m4a), Dolby® Digital (.ac3, .mka), DSD – DSDIFF/DSD (.dff, .dsf), FLAC (.flac, .fla), HEAAC v.1/v.2/level2, LP cm (.mka), Vorbis, WMA10 Pro, and  WMA9 Standard (.WMA). The extensive list of formats can be found at the Sony website. Chances are that this player can handle just about any disc or codec that you have.
The Sony UBP- X800 supports HDR10 which allows for a greater range of color contrast and brightness. There’s no support for Dolby Vision which is better than HDR10 (see my HDR review.) Yet HDR10 seems to currently be more popular and Sony could add Dolby Vision support by a simple software update in the future.
Sony’s Hi-Res audio and handling of other audio files makes this Blu-ray player an exception audio player. It supports Dolby Atmos® and DTS:X, the two leading audio codecs. The X800 easily handled all of the discs that I threw at it including Hi-Res music discs. The built-in Digital Sound Enhancement Engine performed upscaling on CDs that actually improved the sound quality.  It also includes higher-fidelity LDAC support for those with other Sony devices.
You can even play the audio simultaneous through HDMI and Bluetooth. This is a big plus for those who might need a headset while others are watching the television. Also, it allows you to use the free Sony Music Center app on your mobile phone or tablet to stream content wirelessly from the X800 to other connected speakers and devices.
When it was announced at CES this year that the X800 would be developed in partnership with Sony Pictures Entertainment, I expected the picture and sound quality to be exceptional. I wasn’t disappointed.
This player boots up quickly and is extremely quiet. When playing a 4K video with HDR on a 4K HDR television, the picture quality is simply exceptional. In weeks of testing, I never saw any pixilation or artifacts. Color representation was more accurate than most.
This device also has excellent upscaling making regular DVDs and Blu-ray discs. They both looked better than ever. On top of that, if your 4K display doesn’t support HDR, this unit has an HDR-to-SDR converter that employs a proprietary algorithm to improve brightness and color.
Sony 4K Blu-ray Player
I used the convenient front-facing USB port to play both videos and hi-res music.  The interface, shown below, was easy-to-use.  It was also informative showing the format and other information right on the screen.
Sony 4K Blu-ray Player
The supplied remote is simple and includes buttons like a Netflix and Favorite buttons. It operates with IR sensors. My only complaint is that it is not backlit, which is almost essential for movie viewing.
Sony 4K Blu-ray Player
Samsung beat Sony to the market with their 4K Blu-ray player, but the Sony UBP-X800 was worth waiting for. Whether you play 4K discs or older Blu-rays, the picture is excellent and the sound quality is superb. The interface is easy to use and easy to customize. In short, this is an excellent all-around media player that won’t disappoint.