X265 encoding settings to retain source quality

[vovin]

Since x265 is very new I haven't been able to find any guidelines for converting. I want the quality to look about the same while creating the smallest file possible, so how much can I push it?

the video source is 5000kbps and I was thinking of setting the Avg Bitrate to 3000 with 2-Pass encoding, with the x265 preset slider set to Very Slow. Would that give similar quality?

[Deleted User 13735]

All source is different, thus optimum compression ratio is different.
The differences are huge.

For the same reason, I doubt any clear correlation exists between x264 / x265 encode settings.

[vovin]

I guess the best thing to do is take a few seconds and encode it at different settings, then compare each.

By the way i've read posts saying x265 does not show much benefit over x264 for reducing file size, but these posts were several months old. I assume things have changed since the new release? And how are people finding their x265 conversions?

[Deleted User 13735]

I guess the best thing to do is take a few seconds and encode it at different settings, then compare each.

I was hoping to lead you to the conclusion that the results would be valid for only that particular movie.
The "settings" are not fixed points, but fluid, moving targets that are controlled by your unique source at any given point in time.
Nor were x265 algorithms designed to respond identically to x264, to my knowledge.

[vovin]

By the way I have a 3.4ghz core i7 on 64bit, and it takes on average about 8 hours to convert 10 minutes of video for x265 with slow encoding settings. Does that sound right?

At that rate, it should take up to a week to convert a full length movie. It doesn't seem worth it considering the last time I converted a video my power went out, and Handbrake couldn't recover what I already converted so I had to start all over.

[Deleted User 13735]

You're lucky.
x265 should be doing better in a couple of years.
Until then . . .

(Yes, I can confirm that Handbrake shuts down when there is a power outage)

[vovin]

You're lucky.
(Yes, I can confirm that Handbrake shuts down when there is a power outage)

Obviously my surprise is not that Handbrake shuts down when there is a power outage, rather I'm surprised that it can't continue from where it left off when I restart the program.

[Deleted User 13735]

Obviously my surprise is not that Handbrake shuts down when there is a power outage, rather I'm surprised that it can't continue from where it left off when I restart the program.

I can't begin to imagine the buffer space that would require.
But there is a thread where you can post your feature request here:
viewtopic.php?f=14&t=28073

[JohnAStebbins]

Obviously my surprise is not that Handbrake shuts down when there is a power outage, rather I'm surprised that it can't continue from where it left off when I restart the program.

I can't begin to imagine the buffer space that would require.
But there is a thread where you can post your feature request here:
viewtopic.php?f=14&t=28073

Not only would the state information be fairly massive, but it's also not available to us to save. The encoding state of libx265 is internal to that library and there is no way to save/restore it at any given point. It was not designed for that usage model.

[Deleted User 13735]

Now that I look at it again, posting that link was a bit snarky of me.
Apologies and welcome to the forums, vovin.

[Hand On Tha Brizzake]

Since x265 is very new I haven't been able to find any guidelines for converting. I want the quality to look about the same while creating the smallest file possible, so how much can I push it?

Before I explain the settings I use for purposes of highest quality and greatest efficiency I will mention two things. Firstly, I am unaware of the source material you are converting thus I am unaware of the resulting differences compared to what yours currently are. Conversions will no doubt vary from source to source after transcoded to their respective destinations but I will focus strictly on what you mentioned: smallest file size possible. Secondly, considering the time required, most folks may consider this to be overkill but quality and efficiency mean more to me than the time it requires for the system to transcode. Without detailing my profile including picture settings [ask and you shall receive], the quality is always constant, RF setting is always 0, preset is always Placebo, frame rate is always variable and same as source. This in itself should ensure the picture suffers no further compression than the source. It will require many hours but I am in no hurry and the results are worth my while. My mission is to maintain maximum quality – especially because the source is most likely lossy and minimise the destination file's size. Those are my basic parameters for h.265 [x265] – the only codec used here

[Deleted User 13735]

Secondly, considering the time required, most folks may consider this to be overkill

... the quality is always constant, RF setting is always 0, preset is always Placebo,

Yes, that is indeed overkill for compressed Y'(CbCr) source, and any conceivable connection between file sizes using x264 and x265 encoders at lossless settings escapes me completely at this stage of discussion. Are you actually able to play this stuff, or just grab pretty frames?

I would like to see your encode logs for both of the encoders, using identical source and encoder settings (to the degree possible) at RF=0. before carrying this train of thought any further. Run the same trials with all I-frames set, as well. Of course, SSIM and PSNR results from each would be welcome if you're capable of providing those, too. Eagerly awaiting your tests, and
Welcome to the forums!