Color issue in x265 encode

[newpball]

Sounds encouraging, thanks for that info!

[poisondeathray]

@newpball -

This is for x264/AVC , look at post 35 for a clear cut example, of "banding", or lack of in the other case. Both P-frame comparisons, 8 vs. 10 bit x264. 1280x720p 5Mb/s (I wouldn't call this "really low" bitrates for this type of material, it's slow moving, static scenes of lighthouses - so complexity isn't really high)
https://forum.videohelp.com/threads/344136-How-to-encode-anime-to-10bit-x264/page2

I can post part the source clip if you want, I still have it on a HDD archived somewhere. That test was done at lower resolution, but it's from the 1080p master used to make the BD courtesy of Stacy Spears (from Spears and Munsil) for Lighthouses of the Pacific.

[sophisticles]

I'll take it one step further and say that with x265 one should use 16 bit internal precision, if they want the highest quality encode possible with that encoder.

[Evad3R]

It is possible that the original itself is suffering poor quality (which does not allow to improve the final video).

Source :



Video

Format                      : MPEG Video
Format version              : Version 2
Format profile              : Main@Main
Format settings, BVOP       : Yes
Format settings, Matrix     : Custom
Format settings, GOP        : M=3, N=12
Format settings, picture st : Frame
Duration                    : 23mn 37s
Bit rate mode               : Variable
Bit rate                    : 4 736 Kbps
Maximum bit rate            : 6 000 Kbps
Width                       : 720 pixels
Height                      : 576 pixels
Display aspect ratio        : 16:9
Frame rate                  : 25.000 fps
Standard                    : PAL
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Interlaced
Scan order                  : Top Field First
Compression mode            : Lossy
Bits/(Pixel*Frame)          : 0.457
Time code of first frame    : 00:49:14:04
Time code source            : Group of pictures header
GOP, Open/Closed            : Closed
Stream size                 : 800 MiB (78%)

Obviously we need more details, one image is simply not enough information.
Please mention exactly what you think is the problem.

The area within the circle is my problem. That area seems odd.

It's a common misconception. It's beneficial even on a 6bit cheap TN display.

The main reason for using 10bit encoding from an 8bit source is not because of the dithering or bit depth conversion from 8 bit source to 10bit. 10 bit is better for encoding in terms of compression efficiency. The intermediate calculations have a higher level of precision. I was dubious at first too when 10bit AVC became more common a few years ago, but it's pretty much proven at this point. The compression efficiency benefit varies a lot by content. On some sources it might only be 5-10% better at a given bitrate range. Other can be as high as 50-60%. Early testing shows the relationship holds with HEVC for 10bit.

The negatives are compatibility (devices etc...) , slower encoding

Do you say that x264 10bit has better compression than x265?

I can point you to some articles if you want and there are real world tests in various forums as well

I am really interested in reading those articles.

[poisondeathray]

The artifacts in the circle are posterization artifacts. Usually from over denoising. Denoising ruins the natural noise and dither

And how did you take the screenshot ? What software/method ? Sometimes this type of artifact can be due to improper viewing method

Why did you post a different frame of the source ? Logically, you should post one of the same frame ,or a video sample would be even better (from the same source, not from other video ). And what does the script preview post filters , yet pre encoding look like ?

What where your x265 settings ? What x265 version ? There were some changes last month or so to the defaults regarding psy-rd , psy-rdo which should help with this sort of thing

Do you say that x264 10bit has better compression than x265?

Better in some ways, yet worse in others. x265 right now doesn't do as good as a job as x264 retaining noise and dither, which cover up those types of artifacts. But in the future, x265 should become better in all areas

[poisondeathray]

I am really interested in reading those articles.

Some 10bit AVC articles attached below

This Broadcast Engineering link is down, but the Wayback Machine has it archived. Unfortunately some of the charts are missing
http://broadcastengineering.com/hdtv/avch-encoding/index2.html


I'll reproduce some quotes from the Broadcast Engineering article:

Encoding in 10 bits can achieve a PSNR increase of more than 1dB on some natural sequences and measures an average of 0.25dB at 60Mb/s on a varied test set of broadcast HD sequences. This translates to an average savings of about 5 percent and up to 20 percent, while retaining the same video quality.

However, further testing shows that increasing the bit depth to 12 bits (or even 14 bits) provides a much smaller coding efficiency gain (up to about 1 percent in bit rate savings), but again, no loss greater than 8 or 10 bits.

Lastly, there is no relation between 10-bit encoding and the frame format. The advantages are the same whether the source video is HD, SD, progressive or interlaced.
.
.
.
The gains are the result of increased accuracy in internal computations; 8-bit video sources also show improvements. Interestingly, the reduction of artifacts provided by 10-bit processing is perceivable even on standard (8-bit or dithered 6-bit) LCD panels.

[Gravitator]

Why would a man not to give a sample for the selection of settings? It is possible that the original itself is suffering poor quality (which does not allow to improve the final video).

Frankly I would not be surprised the original looks better.

People mentioned that the source DVD (This is alarming that the quality of the weak, not BD).

[Gravitator]

@EvadR3, make 1-5 second sample to investigation

[newpball]

Width : 720 pixels
Height : 576 pixels

Oh boy!

You started with a vertical resolution of about 440+ and you end up butchering that to 304?

Why on Earth would you want to do that?

[Evad3R]

@EvadR3, make 1-5 second sample to investigation

Here you go : Sample

Oh boy!

You started with a vertical resolution of about 440+ and you end up butchering that to 304?

Why on Earth would you want to do that?

I wanted to bring down a 7.4GB DVD to 1.44GB mkv. So, I shrank the screen size.

And how did you take the screenshot ? What software/method ? Sometimes this type of artifact can be due to improper viewing method

I take screenshots by pressing ALT + I in MPC-HC. Sometimes I split around 5 mins sample from the video, download it to the PC, play with VLC and take SS.

Why did you post a different frame of the source ? Logically, you should post one of the same frame.

Source

Approximately same frame

What where your x265 settings ? What x265 version ? There were some changes last month or so to the defaults regarding psy-rd , psy-rdo which should help with this sort of thing

x265 ver. 1.1+45


I guess you refer the following as x265 settings.
Encoding mode : ABR
Preset : Slow
Tuning : None
Frame-Threads : Auto

[newpball]

I wanted to bring down a 7.4GB DVD to 1.44GB mkv. So, I shrank the screen size.

Really I do not understand people sometimes, satisfied with a whopping 304 pixels of vertical resolution to save some space, and for what? I suppose I am crazy, I should really 'help' the poster by telling he is doing a great job and suggesting improvements by changing some encoding parameters.

[poisondeathray]

x265 ver. 1.1+45

You should really upgrade and repeat the test . Probably a few hundred commits since that version. Lots of big changes, even speed

[Evad3R]

Really I do not understand people sometimes, satisfied with a whopping 304 pixels of vertical resolution to save some space, and for what? I suppose I am crazy, I should really 'help' the poster by telling he is doing a great job and suggesting improvements by changing some encoding parameters.

Eagerly expecting some suggestions...

You should really upgrade and repeat the test . Probably a few hundred commits since that version. Lots of big changes, even speed

There is no update for x265 in stable server. Do you want me to update from Dev. server?

[Gravitator]

@Evad3R, strange.... But your sample is fine with me.




It is possible that the player is not properly input/outputs HEVC files. Try through MadVR.

[Evad3R]

@Evad3R, strange.... But your sample is fine with me.



[Attachment 30611 - Click to enlarge]

It is possible that the player is not properly input/outputs HEVC files. Try through MadVR.

Thank you so much for taking time to help me. I really appreciate it.

So, is this an issue with MPC-HC?

[Gravitator]

Need to MPC-HC/LAV/MadVR

Your sample through a hybrid hardware decoding LAV-DXVA gave a crooked playback (I suspect because of the resolution / aspect ratio), but the LAV-CUVID did fine.

[Evad3R]

Need to MPC-HC/LAV/MadVR

Your sample through a hybrid hardware decoding LAV-DXVA gave a crooked playback (I suspect because of the resolution / aspect ratio), but the LAV-CUVID did fine.


[Attachment 30612 - Click to enlarge]

Do you have any perfect solution for taking screenshots from x265 videos over remote?

[Gravitator]

Do you have any perfect solution for taking screenshots from x265 videos over remote?

I also use the save screenshots through the MPC-HC. As it is interesting to hear about the remote to screenshots

Why do it ... What a report / dissertation writing?

[Evad3R]

As it is interesting to hear about the remote to screenshots

Why do it ... What a report / dissertation writing?

I do encoding in server. Since I have a very limited bandwidth, I am unable to download entire movie to my PC for taking screenshots. So, I have installed Free Video to JPG Converter on my server to take screens from x264 & MPG videos. But, Free Video to JPG Converter doesn't support x265.

I hope now you have understood what I meant by screens over remote!


Update

Free Video to JPG Converter now supports x265 videos.


Thank you so much for all who participated in this thread and intended to help me.