[Google Pixel XL Guides, News, & Discussion] oRAirwolf:
Here's the post I made on the Google product forums, using your video as an example:

Somebody on XDA Developers just posted a video they took outside in the sun at 4K. I think one could consider this scene to be ideal conditions. I think this is a good example of how poor the video quality is. I took a screenshot of it at 4K resolution, so you can see the original quality by zooming in if you are not on a 4K monitor.

http://i.imgur.com/u8toyk7.jpg

https://www.youtube.com/watch?v=kz0rxcB9LUM

The clouds in the sky are highly compressed and very blocky. It reminds me of video on my Dreamcast. The falling water has tons of digital noise and the entire image is blocky and covered in compression artifacts. I hope Google will address this, as I have seen better 720p quality video. This is a huge let down.

The Pixel XL is recording 4K UHD video at 42 Mbps in an h264/AVC format. I have videos encoded at the same bitrate that are near flawless. For comparison, here are 2 screenshots from some 4K showcase videos.

This video is at 38.4 Mbps, which is 3.6 Mbps or 9% lower bitrate than the Pixel XL video: http://i.imgur.com/1488tHh.jpg -- Almost no visible compression artifacts, noise, or blockiness.

This video is at 45.3 Mbps, which is 3.3 Mbps or 7.6% higher bitrate than the Pixel XL video: http://i.imgur.com/dGvl6Xv.jpg -- Again, almost no visible compression artifacts, noise, or blockiness.

Pixel XL video and the two demo videos have the same encoding profile (High@L5.1), the same bit depth (8 bit), and the same chroma subsampling (4:2:0). Why is the Pixel's video substantially worse?

Pixel XL video:

Video

ID : 1

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L5.1

Format settings, CABAC : Yes

Format settings, ReFrames : 1 frame

Format settings, GOP : M=1, N=30

Codec ID : avc1

Codec ID/Info : Advanced Video Coding

Duration : 2 min 55 s

Bit rate : 42.0 Mb/s

Width : 3 840 pixels

Height : 2 160 pixels

Display aspect ratio : 16:9

Frame rate mode : Variable

Frame rate : 30.000 FPS

Minimum frame rate : 22.994 FPS

Maximum frame rate : 43.042 FPS

Standard : NTSC

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Bits/(Pixel*Frame) : 0.169

Stream size : 878 MiB (100%)

Title : VideoHandle

Language : English

Encoded date : UTC 2016-10-31 08:09:44

Tagged date : UTC 2016-10-31 08:09:44

Color range : Full

Color primaries : BT.601 NTSC

Transfer characteristics : BT.601

Matrix coefficients : BT.601

mdhd_Duration : 175328

First Example:

ID : 1

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L5.1

Format settings, CABAC : Yes

Format settings, ReFrames : 4 frames

Codec ID : V_MPEG4/ISO/AVC

Duration : 1 min 32 s

Bit rate : 37.2 Mb/s

Width : 3 840 pixels

Height : 2 160 pixels

Display aspect ratio : 16:9

Frame rate mode : Constant

Frame rate : 29.970 (30000/1001) FPS

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Bits/(Pixel*Frame) : 0.150

Stream size : 408 MiB (97%)

Writing library : x264 core 142 r2479 dd79a61

Encoding settings : cabac=1 / ref=4 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=12 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=15.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=50000 / vbv_bufsize=60000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00

Language : English

Default : Yes

Forced : No

Color range : Limited

Color primaries : BT.709

Transfer characteristics : BT.709

Matrix coefficients : BT.709

Second Example:

Video

ID : 1

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L5.1

Format settings, CABAC : Yes

Format settings, ReFrames : 4 frames

Codec ID : V_MPEG4/ISO/AVC

Duration : 2 min 27 s

Bit rate : 44.2 Mb/s

Width : 3 840 pixels

Height : 2 160 pixels

Display aspect ratio : 16:9

Frame rate mode : Constant

Frame rate : 29.970 (30000/1001) FPS

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Bits/(Pixel*Frame) : 0.178

Stream size : 775 MiB (98%)

Writing library : x264 core 142 r2479 dd79a61

Encoding settings : cabac=1 / ref=4 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=12 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=15.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=50000 / vbv_bufsize=60000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00

Language : English

Default : Yes

Forced : No

Color range : Limited

Color primaries : BT.709

Transfer characteristics : BT.709

Matrix coefficients : BT.709