x264 compatible settings

[nixiejames]

i just recently started making backups of my blurays using the default settings of the very slow preset.
there's a parameter called reference frames that i do not fully understand. i don't really plan on learning it much but i just read that one should limit it to 4 for compatibility.

my question is, what parameters should i limit and at what value for universal x264 compatibility. like if the tv/bluray player supports x264, i know those settings will work.

[jagabo]

There's no such thing as universal h.264 compatibility. Different devices have different abilities. Most Blu-ray players and current TVs with built in media players can handle Blu-ray compatible settings. But x264's veryslow preset has many settings that are not Blu-ray compatible. Problematic settings include too many consecutive b-frames, too long keyframe intervals, too many reference frames, to high bitrates, etc. You'll need to modify the preset:

http://www.x264bluray.com/home/1080i-p

Be sure to put all the modifiers AFTER the preset.

[hello_hello]

High Profile, Level 4.1 support seems pretty standard these days. Sometimes Level 4.2. I've never met a Bluray capable of playing MKV or MP4 via USB that required them to be encoded using Bluray compliant settings. Your player/TV's manuals will hopefully a mention a Profile and Level, and in a perfect world, any other restrictions required, but if you set the appropriate level and a speed preset uses settings that exceed it, the level setting should take precedence. If you specify an individual setting in the command line, that should take precedence over the Level..... I think.

https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

x264 doesn't enforce bitrate restrictions according to the level you set, but it rarely matters. Most players handle pretty high bitrates. This is what I use for Bluray to MKV encoding:

program --level 4.1 --preset slow --tune film --crf 18.0 --vbv-bufsize 50000 --vbv-maxrate 50000 --colorprim bt709 --transfer bt709 --colormatrix bt709 --output "output" "input"

For level 4.1 the compliant VBV settings are --vbv-bufsize 78125 --vbv-maxrate 62500, but I torture tested the media player in my TV one day and that's what was needed for it not to stutter, but either way, it's way higher than the bitrates most of us use.

Of course if you're making those discs thingies, it probably wouldn't hurt to ignore me and follow jagabo's link, although I do wonder how necessary all that is these days. I know it's "official" but the spec must be over 10 years old. Even my four year old smartphone can power through Level 4.1 at 1080p.

[LigH.de]

Often differences are tiny but important ... "x264" is one (out of many) possible encoder software producing a video stream compliant to the "H.264" standard written in a technical document. There are other encoders, which are not called "x264", still they produce H.264 video streams. Players (or rather, their decoders) may support video streams compliant to the H.264 standard, whether or not the x264 encoder produced them.

Consumer players have limits, mainly regarding the reading speed from the media, the decoding speed (including some details about the complexity of the video), and the size of the decoding buffer. These limits are described in the "Profile@Level" pair you may find in technical documents. Unfortunately, most user manuals are written without sufficient details for the tech-savvy user. You may have to guess from other general sources of information which maximum Profile@Level the decoder in your specific playback device supports, to know how to set up a H.264 encoder (e.g. x264) so that it produces a video stream compatible to your device.

Most "Blu-ray compatible" modern devices should support High Profile @ Level 4.1 or even 4.2; older mobile devices (pads, smart phones - especially with less than FullHD resolution) may be restricted to Main Profile @ Level 3.x.

[nixiejames]

thank you jagabo, hello, and ligh.de!

i've checked your links but like hello said, i'm not sure how updated they are. right now i'm using the device option of staxrip which has blu-ray. there are some differences such as keyint being 48 instead of 24 and no bt709 commands.

[_Al_]

those links are not old, x264 Blu-ray encoding stands correct and that level-fps-bitrate-ref.frames table stands also, rules did not change

you seem to encode to a particular device, not getting a "normal" device that plays standards, basically you encode for a crippled device (if that is a case), I'd just encode a test file, regular, decent file, if I can call it like that :

x264.exe --CRF 18 --ref 4 --vbv-bufsize 30000 --vbv-maxrate 30000

or just using a GUI try to set profile medium (that is default that is why it is not in command line), set buffers to those 30.000 limits, make sure ref frame is not higher that 4, or rather you can set 3, because if you tweak settings, it might change to 4 anyway (not sure, pyramid takes 1 ref frame)

if your player plays that, you might save 5-10% on hardisk space, Blu-Ray streams get a bit bigger (using CRF ) because of its limitations ...

[hello_hello]

thank you jagabo, hello, and ligh.de!

i've checked your links but like hello said, i'm not sure how updated they are. right now i'm using the device option of staxrip which has blu-ray. there are some differences such as keyint being 48 instead of 24 and no bt709 commands.

It's not the links that'll be out of date. The specs haven't changed. I was just wondering how likely it'd be for players to require spec compliant video these days. I don't know as I've never created a Bluray compliant disc myself, but I've not met a USB capable Bluray player that won't play level 4.1. My other half has an older Sony Bluray player she bought a year or so before USB inputs became fairly common, but it'll still play Level 4.1 h264 in an MKV if it's burned to disc.

Anyway..... keyint 48 is apparently allowed if you restrict the bitrate. The rules are explained in detail here.
http://forum.doom9.org/showthread.php?t=154533
I'd assume StaxRip would set that accordingly. From what I understand reading the info in the link, it'd mean using this:
--vbv-maxrate 15000 --vbv-bufsize 15000
I've got an older StaxRip installed and it doesn't set the lower VBV vlaues in the encoder configuration but I can see -keyint 48. I'm not sure why. Maybe StaxRip fiddles with some settings when it starts encoding. I'm not sure.

You can set bt709 yourself. For the version of StaxRip I have it's under the Misc tab in the encoder configuration. The ones you want are Color Primaries, Color Matrix and Transfer (characteristics). They have no effect on how the video is encoded, they just write colorimetry info for a player to use on playback, if it's so inclined. Without them I'd imagine for 720p or 1080p players would just assume bt709 anyway, as it's the standard for HD.