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Terrible YouTube compression

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Ray Uri
Terrible YouTube compression
on May 6, 2014 at 2:00:40 pm

I have problem with YouTube compression. Please, look at pictures. (original exported video) (uploaded compressed YouTube) (comparsion)

Exported video is:
Complete name : D:\Video\- Render\SoM - Bitter Coast
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt
File size : 3,17 GiB
Duration : 10mn 25s
Overall bit rate : 43,5 Mbps
Encoded date : UTC 2014-03-14 12:26:09
Tagged date : UTC 2014-03-14 12:44:59
Writing library : Apple QuickTime
©TIM : 00:00:00:00
©TSC : 25
©TSZ : 1

ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L5.1
Format settings, CABAC : Ne
Format settings, ReFrames : 2 frame
Format settings, GOP : M=1, N=15
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 10mn 25s
Bit rate : 42,0 Mbps
Width : 1 920pixely
Height : 1 080pixely
Display aspect ratio : 16:9
Frame rate : 25,000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.810
Stream size : 3,06 GiB (96%)
Language : English
Encoded date : UTC 2014-03-14 12:26:09
Tagged date : UTC 2014-03-14 12:44:59
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

ID : 2
Format : PCM
Format settings, Endianness : Little
Format settings, Sign : Signed
Codec ID : sowt
Duration : 10mn 25s
Source duration : 10mn 25s
Bit rate : 1 536 Kbps
Channel(s) : 2 kanály
Channel positions : Front: L R
Sampling rate : 48,0 KHz
Bit depth : 16 bits
Stream size : 114 MiB (4%)
Source stream size : 114 MiB (4%)
Language : English
Encoded date : UTC 2014-03-14 12:26:09
Tagged date : UTC 2014-03-14 12:44:59

ID : 3
Type : Time code
Format : QuickTime TC
Duration : 10mn 25s
Time code of first frame : 00:00:00:00
Time code settings : Striped
Language : English
Encoded date : UTC 2014-03-14 12:44:59

And after upload on YT it looks absolutely ugly, especially during moving scenes:

But some channels have really clear and sharp videos. Is it depends on "premium" accounts? Any suggestions? Thanks.

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Craig Seeman
Re: Terrible YouTube compression
on May 6, 2014 at 3:38:19 pm

Your encoder settings are pretty good. I could make minor suggestions for improvement but ultimately you're seeing limits on YouTube's side.

My suggestions would be up the data rate to 50Mbps. Use High Profile CABAC. Doing this will only help very little though.

Also, as per your comparison, you may want to use processing filters to compensate for the changes YouTube's encoder is making in your black and gamma.

Some things such as "water motion," clouds, camera movement, transition are very big challenges for encoders since pixels are changing every frame and codecs use that to decide what information gets thrown out.

Here's YouTube's recommendations:

You might want to consider having a look a Vimeo Plus. Must be Plus for 1080 and better encoding on their end.

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Ivan Myles
Re: Terrible YouTube compression
on May 6, 2014 at 8:15:09 pm
Last Edited By Ivan Myles on May 6, 2014 at 8:47:38 pm

I agree with Craig's points. As an extension of his comments, I see two primary issues: 1) the low bitrate of YouTube videos, and 2) the bitrate-hungry nature of the source video. Vimeo's x264 encoder is a little more efficient and should produce better results, but may not resolve the problem.

Low bitrate encoding produces the highest image quality when change is minimized; you want to construct shots so that pixels can be reused from frame-to-frame to the greatest degree possible. For example, a flat pan is better than a camera swivel because the image can just be repositioned in the following frames. Similarly, don't move the camera when there is a lot of motion/change in the shot.

Here are some things to consider when trying to improve the quality of low-bitrate video:

- degree of change within the subject matter
- level of image detail
- camera movements and/or changes in perspective
- length of each shot (i.e. frequency of cuts)
- framerate and frame dimensions
- codec and encoder settings

On one extreme, HD movies with high motion, quick cuts, detailed images, and moving cameras will need to be encoded at high bitrates to look good. At low bitrates shots should be simplified if you want to produce good quality.

FYI: The file you submitted is 0.81 bits/pixel at 1080p. YouTube typically transcodes video to about 0.07 bpp. Apple uses around 0.12 bpp. I typically target 0.15-0.20 bpp at 480p for high quality streaming and provide a hi-def version for downloading.

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