Handbrake: what does the Optimize Video slider do?

[Valmont]

Handbrake: what does the Optimize Video slider do?
I read the manual but it doesn't explain. The video quality slider I is in the manual, but not the x.264 quality slider (fast/slow).

[_Al_]

Do you mean preset?

[Valmont]

Ah thanks! That explains it.

[_Al_]

Better to choose those values in the middle. Faster maybe rather not, medium or slow, if slower or very slow I'd also include:
ref=4
for HD video, 1920x1080 in that additional options box to make sure video does not have more than 4 reference frames. For 1280x720 it could be ok I guess, it takes more reference frames to fill memory (buffer). SD resolution creates plenty of room.

If setting slider more towards left, it is less demanding to decode (fast decode check is extreme). So if playing video using very weak hardware , it helps.

[hello_hello]

Is Handbrake doing things differently to the CLI version of x264?

For the CLI version, all you have to do is specify a profile and level (ie High Profile, Level 4.1), and x264 will limit the number of reference frames according to the resolution, even if you select a speed preset that'd otherwise use a higher number of reference frames. You can over-ride that by specifying a number of reference frames in the command line yourself, but if you don't, x264 will keep the relevant settings within the limits of the selected profile and level.
Except for the VBV settings. I doesn't automatically enforce them.
For 720p, Level 4.1, High Profile, the ref frame limit is 9. https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

Maybe Handbrake is doing it's own thing. Some of the command line settings in the screenshot above are different from the VerySlow x264 defaults. Does Handbrake still use presets of it's own?

[Valmont]

What's this "Level" thing? Like Level 4.1. And what's this ref thing, like ref=4. Cheers.
I've opened a can of worms but so be it .

[jagabo]

https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Profiles
https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels
https://en.wikipedia.org/wiki/Reference_frame_(video)

A large part of video compression involves not repeating parts of the frame that don't change from other frames. The more data you can copy from other frames the less bits you need to encode the current frame. The number of reference frames is the number of other frames a frame can copy data from. More reference frames requires more memory when decoding because all the reference frames need to be in memory (and decompressed) in order to copy from them. More reference frames leads to longer encoding times as the encoder has to search through more frames looking for data to copy.

[_Al_]

I'd just add that Level is just a sort of label, it does nothing. It just a function, as was explained, of resolution, bitrate , frame rate or better capacity for memory. That lebel could be overwritten manually, I'd say, to lie to a hardware device and pretend level is fine, like 4.1 even if technically it should be 4.2 for example.

Some players would read 4.2 or something and refuse to play the video thinking it is out of specs, even if they would be capable to play it. Or at least it used to be like that years back. Today hardware players perhaps just play whatever.

But all those frame rate, resolution, bitrates and reference frames play a role that if combined it should follow specs. x264 uses that to come up with level if you do not specify that based on that. But it does not uses real bitrates , it encodes, it uses vbv-maxrate and vbv-bufsize for its equations. So if you have those buffers set to 60000 or 70000, it would set levels to 4.2, not 4.1. Values that high is a nonsense anyway. It should be 30000 to 40000 max.

Example:
Then if having preset set to MEDIUM, buffers to about 35000, using 1920x1080, 4 ref frame in x264 command line., x264 would come up with level 4.1 if not specified.
At the moment you raise buffers above 60000 it might come up with level 4.2.

At the moment you set preset to "very slow" for example, x264 bumps up some values and numbers of reference frames as well to get better compression and that leads into "forbidden" territory for Blu-Ray specs for buffer capacity because it bumps up number of reference frames, more frames needs to be stored. Nobody cares if you are going to play that file on PC, or today's hardware players handle that as well, but just for the sake of explaining, older hardware devices might give you trouble. So you just might override it setting "very slow" and reference frames manually to 4. Of course you lower the comprehensibility a bit as well, but older hardware players would not choke up. That's theory.

[hello_hello]

What's this "Level" thing? Like Level 4.1. And what's this ref thing, like ref=4. Cheers.
I've opened a can of worms but so be it .

It's an automatic set of constraints a player should conform to. If it supports Main Profile Level 3, for example, and you set that when encoding, the encoder should make sure most settings conform to that specification so you can be sure it'll play.

At the moment you set preset to "very slow" for example, x264 bumps up some values and numbers of reference frames as well to get better compression and that leads into "forbidden" territory for Blu-Ray specs for buffer capacity because it bumps up number of reference frames, more frames needs to be stored. Nobody cares if you are going to play that file on PC, or today's hardware players handle that as well, but just for the sake of explaining, older hardware devices might give you trouble. So you just might override it setting "very slow" and reference frames manually to 4. Of course you lower the comprehensibility a bit as well, but older hardware players would not choke up. That's theory.

x264's --bluray-compat option keeps many things Bluray compliant. It doesn't enforce everything, but it does limit the number of reference frames. Just as setting a profile and level should keep ref frames compliant with that level.

http://forum.doom9.org/showthread.php?p=1493513
https://github.com/saintdev/x264-devel/commit/f9e7f531048df7219a44203031c8f79bae6170d0

As long as you stick to correct frame rates and resolutions etc, the following would be Bluray compliant:

--level 4.1 --bluray-compat --preset veryslow --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

Mind you I've not yet met a Bluray player with a USB input that won't play standard High Profile Level 4.1 in MP4s or MKVs. They don't require the additional settings for Bluray video compliance.

[Valmont]

Oh wow I can't believe I read all this but the cohesion between these settings and labels are unfolding now. Thank you so much for your help. At least I know what I'm doing now.

[Valmont]

As long as you stick to correct frame rates and resolutions etc, the following would be Bluray compliant:

--level 4.1 --bluray-compat --preset veryslow --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

Mind you I've not yet met a Bluray player with a USB input that won't play standard High Profile Level 4.1 in MP4s or MKVs. They don't require the additional settings for Bluray video compliance.

Ah I see, so blu-ray player compatibility is a standard for post-processing videos. It's not mine though. Things run off a media server on my NAS, it streams to my TV. My concerns are optimizing filesize vs quality whilst at the same time converting True-HD and DTS audio formats as my TV can't read them.

[_Al_]

It is not a standard, hello-hello points this out , I was just using it as a more friendly compatibility example. You do not have to limit that ref frame number, ..., but there might be some hardware box that would report that cannot play that video. Today, very unlikely perhaps. Remember you use CRF setting so the result of using less ref frames would be just about a bit increased overall size but quality would be almost the same.

I'd get some media box, today they run about $50 and they are very powerful playing even HEVC , you can get even Android based box, so you can keep original audio. They would stream your videos from NAS to your TV. If you are not running video thru a receiver - not sure now, if using KODI aplication for video playback in Android , for example, you might set audio output so your TV would read that. Check that out.

[jagabo]

With x264 the big differences in size are between the ultrafast, superfast, and veryfast presets. From there on out file sizes don't get much smaller (maybe another 5 percent). Visual quality continues to improve up to about the slow preset. Beyond that there's very little difference.

Your TV's media player isn't likely to handle much beyond blu-ray specs. For example, the veryslow preset allows up to 16 reference frames and few devices outside a full blown computer can handle that at 1920x1080 (BD is limited to 4 at that resolution).

[ron spencer]

This is good advice for encoding in general :

As long as you stick to correct frame rates and resolutions etc, the following would be Bluray compliant:

--level 4.1 --bluray-compat --preset veryslow --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

Mind you I've not yet met a Bluray player with a USB input that won't play standard High Profile Level 4.1 in MP4s or MKVs. They don't require the additional settings for Bluray video compliance.

I record in 1920x1080 and 60fps DNxHD for home movies and kids sporting events/teams, etc.

1920x1080 and 60fps is not BluRay compliant, so in Handbrake I just use 1280x720 60 fps, which is BluRay compliant, and the above commands in Handbrake and I have compliant files I can author for other parents who want discs to play. Easy!

[Valmont]

I'd get some media box, today they run about $50 and they are very powerful playing even HEVC , you can get even Android based box, so you can keep original audio. They would stream your videos from NAS to your TV. If you are not running video thru a receiver - not sure now, if using KODI aplication for video playback in Android , for example, you might set audio output so your TV would read that. Check that out.

Never heard of a mediabox. Seems promising. I'll check it out. It's such a burden converting and tweaking so many movies. But DTS support still seems a challenge. I'm eyeballing this one for example: mede8er MED800X3D. Doesn't support DTS it looks like.

[_Al_]

sorry for terminology, media box I meant any media box player, today there is tons of Android based media players, there is a lot of HTPC's like NUC and many , many other devices ...

That mede8er MED800X3D, for its price it better handle DTS, I think it supports it. But it is more than 3 years old and expensive. Bad choice, imho. Watch how old those devices are. Check those previews on Amazon and look at those dates. 3-4 years is a pre-history with these electronics.

If picking Android box, the same problem , look for dates on previews (on Amazon, even if you buy it elsewhere). Android box has to be new. 2016. Those have latest versions of Amlogic SoC ,that are fast enough. You can have that box for around $60 + you get proper remote control about $20 (mini keyboard with touchpad on it). I checked most popular app for video playback Kodi and it has a choice in there to downconvert to stereo on the way out, so no problem there with any audio. But this feature should be today a must with any device I guess, with firmware (mostly older media players) or software app/software playback players.

[hello_hello]

This is good advice for encoding in general :

As long as you stick to correct frame rates and resolutions etc, the following would be Bluray compliant:

--level 4.1 --bluray-compat --preset veryslow --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

Mind you I've not yet met a Bluray player with a USB input that won't play standard High Profile Level 4.1 in MP4s or MKVs. They don't require the additional settings for Bluray video compliance.

I record in 1920x1080 and 60fps DNxHD for home movies and kids sporting events/teams, etc.

1920x1080 and 60fps is not BluRay compliant, so in Handbrake I just use 1280x720 60 fps, which is BluRay compliant, and the above commands in Handbrake and I have compliant files I can author for other parents who want discs to play. Easy!

Damn! Someone finally says I give good advice and I have to go and contradict myself.
Actually, I left out a setting. I'm so used to MeGUI automatically setting --keyint according to the frame rate I forget about it, but Bluray compliance also requires a 1 second maximum key interval, so for 24fps Bluray it should be:

--level 4.1 --bluray-compat --keyint 24 --preset veryslow --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

Which is why I wouldn't encode for Bluray compliance as a rule myself, because the shorter than usual --keyint (the default is 250) can reduce compression by a fair bit. Around 10% if memory serves me correctly.

[Valmont]

That mede8er MED800X3D, for its price it better handle DTS, I think it supports it. But it is more than 3 years old and expensive. Bad choice, imho. Watch how old those devices are. Check those previews on Amazon and look at those dates. 3-4 years is a pre-history with these electronics.

So what do you say? https://www.amazon.com/AKASO-M8S-Octa-core-Bluetooth-Streaming/dp/B01FFAKI6A/ref=sr_1_...ustomerReviews

[_Al_]

https://en.wikipedia.org/wiki/Amlogic
http://www.cnx-software.com/2016/01/29/amlogic-s905-vs-s812-benchmarks-comparison/
best critical review that generalizes what to do with those devices, like remote sucks (it is expected), privacy issues with those devices (someone in China put it together ) etc., not scaring you, that is a common thing for all of those devices today https://www.amazon.com/gp/customer-reviews/R2WOEJVZ63CNHR/ref=cm_cr_arp_d_viewpnt?ie=U...R2WOEJVZ63CNHR
Not bad, it is not latest SoCs (S9 family) it is SoCs (S8 family) but fastest S812, witch have a bit better benchmark results than S905, there are S912 units already released nowadays as well, there were some links around, this is not a concern if playing regular H.264 video, only if trying to play high bitrates over 30Mbit/s or HEVC, 4k 60p, high bitrates you really need to have even a more power available where that S912 is perhaps even better

you can search android s912 on amazon it will come up with something
S905 vs. S912
http://www.cnx-software.com/2016/09/19/amlogic-s905-vs-amlogic-s912-benchmarks-comparison/
so if are not playing 3D, 4k VP9 (hardware decoding), not messing with HDR, you do not need S912

also I forgot latest models (S912) have Marshmallow Android 6.x some S905 might have lollipop 5.x, that unit of yours uses even older version it has Android 4.4,
so you see in Android world it is always better to choose latest model imho