What is prefarable?

[Bigo2]

If I want to create a smaller size video from a large high quality one (using Handbrake) what would be preferable?
Size 2Gb / 1080p / 5000 kb/sec
or
Size 2Gb / 720p / with whatever resulting frame rate?

[Woodstock]

Preferable to whom?

Quality is subjective.

[mduell]

Quality based encoding would be preferable.

[Bigo2]

Thanks.
Preferable to whom? Preferable to a common user.
The quality in both cases concerns two factors: The Dimensions (Width x Height) and the Bitrate. If I want identical (or similar) file sizes, then what should I go for? 1920 x 1080 with a lower bitrate or 1280 x 720 with a higher bitrate?
Of course I know that 1920 x 1080 is better than 1280 x 720 but actually I don't understand how important is the bitrate. If e.g. in the first case it would be 5000 kb/sec and in the second case perhaps 8000 kb/sec does it matter much?
As far as the size of the screen is concerned it is 60"...

[mduell]

If you choose a different bitrate, the file will be a different size, so I'm not sure what you're chasing here, file size or quality.

Regardless, use quality based encoding with a reasonable quality target (like an RF in the low 20s).

[Deleted User 13735]

The theoretical bitrate factor is (1280x720) / (1920x1080) = ?
Not real-world, but close.

[mduell]

Only if you're using some delusional bits per pixel methodology.

[Deleted User 13735]

Of course, how silly of me. It's only a simple pixel count ratio, so please post your bitwise math to enlighten.
;?)

[Woodstock]

Preferable to whom? Preferable to a common user.

Sorry, we don't see them here very often. We see people who want 20:1 compression AND smooth transitions between scenes with blacks that are REALLY REALLY BLACK, even when examined with a 30x power magnifying glass, all at 120 frames per second so that YouTube will "display it properly"....

[Bigo2]

Thanks for your answers, unfortunately they are quite noncommittal...
Or perhaps you don't understand my broken English, so I'll try to ask once more:
It concerns a series with about 110 episodes. Files format is mkv.
I can have a higher quality, each episode something like this:
File size : 4.36 GiB
Duration : 45 min 28 s
Bit rate : 13.6 Mb/s
Width : 1 472 pixels
Height : 1 080 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
or
I can have a lower quality, each episode something like this:
File size : 2.18 GiB
Duration : 45 min 28 s
Bit rate : 6 678 kb/s
Width : 976 pixels
Height : 720 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
(Both details are from the same episode, the audio is exactly the same)

I want to keep the series and I would prefer the higher resolution, but the overall size would be nearly 500 GB, so I thought I could convert those 1080, 4.37 GB files, and instead of the 13 Mb/s I would find the bitrate which would give me 2.18 GB - similar size like the 720 files.
It would be quite big job to convert all episodes, but I don't mind.
However, what I'm not sure about is:
Should I get that 720 version and do nothing or is it better to get the 1080 version and convert all the episodes keeping everything as is, except lowering the bitrate to finish with smaller files?
When converting I usually set the AVG Bitrate, 2-pass Encoding, Turbo first pass, Encoder Preset Slower...
Thanks for your attention

[mduell]

Get the 1080, keep it 1080, and use a reasonable quality target (like an RF in the low 20s).

[Bigo2]

Thanks mduell, I have converted the 4.36 GiB file, keeping everything except the bitrate, which I set in the AVG Bitrate to 6600 kb/s, 2-pass Encoding, Turbo first pass, Encoder Preset Slower...
The resulting file is 2.16 Gib, for I'm surprised because it has almost the same bitrate as the 720 version, but it is actually smaller...
With Regards

[mduell]

Sure, keep ignoring my advice.

[Bigo2]

mduell, do you mean ignoring your advice to use RF in low 20s? I'm not ignoring it. I tested using 2-pass encoding and Avg Bitrate set to 6600 kb/s. That was BEFORE your Thu Jun 07, 2018 12:47 pm reply where you recommend to use RF in low 20s...
Now I just tried the RF 20. The resulting file size is 2.02 GiB and the Bit rate is 6 049 kb/s.

Encoding settings: cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=9 / 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=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=25000 / vbv_bufsize=31250 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00

[mduell]

Move it up to 23 and see if you can discern a difference. Should ~halve your bitrate.

[Bigo2]

mduell - I just tried the RF 23, yes the bit rate is about half as compared with the RF 20 (2 907 kb/s), and also the resulting file size which is 1.00 GiB GiB. The picture seems to be OK and on my PC, I don't see any difference as compared with the previous RF20 / 6049 kb/sec one. So I should be able to reduce the overall size of the entire series quite drastically.
I need to find some more information concerning the bit rate, to learn how it is all related...

[Woodstock]

The relationship of bit rate to quality is rather complex. If there is no specific reason to use a particular bit rate, single-pass, quality-based encoding is better overall.

[Bigo2]

And the quality based encoding means...?

[rollin_eng]

https://handbrake.fr/docs/en/1.1.0/work ... ality.html

[Bigo2]

Thanks - I know about these quality settings, I thought that there will be some fine tuning revealed, special presets. Something like, set this to the following value... because... and so on.

[rollin_eng]

Just select the preset that matches your device/situation.

[Woodstock]

"Fine tuning" the presets is something that involves either (a) a detailed knowledge of each parameter and its effects on output, or (b) a whole lot of trial and error.

Some people try to short-cut (a) by watching youtube videos of people who post youtube videos describing their "fine tuning", ignoring the fact that youtube itself "fine tuned" their videos with a sledge hammer after they were submitted, so all the tuning effects are blown away.

The presets are the result of (a)-type people working on things. I don't, so my "fine tuning" consists of changing audio/subtitle settings.

[Bigo2]

Over the years I too "fine tuned" my settings according to my needs and recommendations found on various video forums. I'm quite happy with them but sometimes I wonder if I have done everything properly. Is there some "central" place where people can share and exchange their findings?
Actually I know, it's here, isn't it?

[mduell]

Few of the users here understand the encoders well enough to provide useful insight into specific settings. doom9 would probably be the place for it.

The reality is that the preset and tune system is the best practice for most users. Other than that the encoder is quite advanced for doing the right thing without configuration.

[Bigo2]

Thanks guys for helping me
Regards