Advanced x264 Options - 8x8 DCT Compatibility

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lemon
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Advanced x264 Options - 8x8 DCT Compatibility

Post by lemon »

Just wanted to share with others that the 8x8 DCT option under the advanced x264 settings is not compatible with Apple TV. Video encoded with this option enabled will play back in Quicktime and also in iTunes on a Mac but will not sync to the Apple TV. The encoded movie was added to my iTunes library just fine and plays back without any problem on my Mac mini, but the Apple TV sync process will give you an error saying that the format is not supported.

It may be of help if this can be added to the Wiki or the pop-ups on the x264 advanced options tab.
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s55
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Post by s55 »

This is exactly why we strongly encourage people to use the AppleTV preset. (or the preset for the relevant device)

These pre-sets undergo a lot of work / testing and are generally aimed at producing good quality.
jbrjake
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Post by jbrjake »

Why would anyone expect 8x8dct to work on the AppleTV? The tech specs ( http://www.apple.com/appletv/specs.html ) clearly state that the AppleTV only handles main profile h.264. Both the wiki and tooltip note that 8x8dct is a high profile feature. I'm not going to list every single consumer electronics device that's not high profile compatible -- it'd take forever.

I'm working on a different solution to this recurring problem -- people not being sure what works with what. Instead of noting it down in documentation not everybody reads, the app should tell you itself in warning messages. ....I've got a post I'm writing that'll pop up in the dev forum soon
realityking
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Post by realityking »

Do you know any consumer device that plays high profile (with the exception of HD DVD/Blu Ray players)?
Anamonde
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Post by Anamonde »

MacMini :wink:
Leo
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Post by Leo »

Why would anyone expect 8x8dct to work on the AppleTV? The tech specs ( http://www.apple.com/appletv/specs.html ) clearly state that the AppleTV only handles main profile h.264. Both the wiki and tooltip note that 8x8dct is a high profile feature. I'm not going to list every single consumer electronics device that's not high profile compatible -- it'd take forever.
Yes, but it would be useful to quickly list what breaks AppleTV compatibility in the wiki at
http://handbrake.m0k.org/trac/wiki/x264Options

...along with a little section on iPod compatibility :)


Here, I'll do some of it for you, just cut and paste:

AppleTV compatibility
The AppleTV cannot handle High Profile x264 options. The following are High Profile options which break AppleTV compatibility:
  • • b-pyramid
    • mbaff
    • 8x8dct
    • cqm
[I'd also iterate that CABAC can make it struggle and is not recommended. Also I seem to remember there being a bframe limit? refs limit too?]
The audio bitrate should be 160 or less.

iPod Compatibility
The iPod 5.5G can only handle x264 level 3.0 complexity. It also cannot handle the High Profile options listed above or any of the following:
  • • CABAC
    • brames
    • large numbers of reference frames (variable depending upon resolution)
    • more than 1200 macroblocks (equivalent to 640x480 pixels)
    • average video bitrate above 1500
    • video bitrate buffer size above 2000
    • audio bitrate above 160 (? is that right)
Video widths larger than 640 pixels, such as 720x400 or 720x304, are compatible with the iPod itself (providing they do not exceed the 1200 macroblock limit), however iTunes refuses to transfer them. Other programs, such as Floola [Link] can be used to transfer them.
The iPod also supports anamorphic encoding, so it is possible to use 704x432 for 2.35:1 PAL movies (by cropping the standard 720x436 very slightly), or 720x368 for NTSC movies.

Voilà :wink:
Last edited by Leo on Sun Oct 07, 2007 8:10 pm, edited 4 times in total.
dynaflash
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Post by dynaflash »

Leo wrote:
Why would anyone expect 8x8dct to work on the AppleTV? The tech specs ( http://www.apple.com/appletv/specs.html ) clearly state that the AppleTV only handles main profile h.264. Both the wiki and tooltip note that 8x8dct is a high profile feature. I'm not going to list every single consumer electronics device that's not high profile compatible -- it'd take forever.
Yes, but you could take 2 minutes to list what breaks AppleTV compatibility in the wiki at
http://handbrake.m0k.org/trac/wiki/x264Options

...along with a little section on iPod compatibility :)
Leo, be real, we are not gonna list *everything* that breaks AppleTV and iPod compatibility. That is simply ridiculous.
Leo
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Post by Leo »

well, ok, but I still think something like I've listed above would be very useful to many HandBrake users!

...are there more options that break compatiblity? I've listed the ones I've heard talked about most in various places. There presumably are vbv limits for AppleTV too but I don't know them.

I think the presets are good, but would also like to see a bit of other guidance for folk.

(Also, apologies for sitting submit before when I meant to hit preview.)
dynaflash
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Post by dynaflash »

Leo wrote: There presumably are vbv limits for AppleTV too but I don't know them.
A search for AppleTV and vbv would have turned up this thread http://handbrake.m0k.org/forum/viewtopic.php?t=2515
Leo wrote: I think the presets are good, but would also like to see a bit of other guidance for folk.
Leo, we do the best we can with the time we have. Feel free to help people out if you can and have the time. The presets should work for anyone that just wants to click and encode. Beyond that its up to you to do some of your own searching. Most things are here in the forums and with a bit of digging you should be able to find them
Leo
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Post by Leo »

Beyond that its up to you to do some of your own searching. Most things are here in the forums and with a bit of digging you should be able to find them
I usually do search but find it very difficult to find the answers, and end up wasting a lot of time. That is why I suggest changes to the guides, so others don't have to spend ages searching.

Do you think it would be a bad idea to include my suggested sections in the wiki?
jbrjake
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Post by jbrjake »

Leo wrote:Do you think it would be a bad idea to include my suggested sections in the wiki?
Yes, because it opens us up to "Why don't you have information on what's compatible with *my* device?!" whining from everyone, and leaves us with the burden of *maintaining* and *fact-checking* all that information, which is the real time sink. What's worse than no information? Outdated and/or unreliable information.
Leo
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Post by Leo »

That's a bad attitude to have, jbrjake. The forum has plenty of people who would benefit from such guidance being included in the wiki; and it obviously doesn't help if you intentionally conceal it.

For a start, this entire thread, and all the posts in it wouldn't have needed to exist. And I am sure there are a fair number more!

iPod and AppleTV are clearly by far the most common devices anyway. Perhaps the x264 options page is not the best place to go into detail about compatibility, but there is definitely an obvious deficit in the guide/wiki by not including this! (duh)

So you're still not going to include it are you? Rather disappointing, mate.
Terc
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by Terc »

I also am looking for exactly what settings break Apple TV Compatability. Eliminating the need for each person that visits the forums from needing to ask this question, then go off and independantly discover the answer is a waste of a lot of people's time. I would volunteer to help if my work would be posted outside the forums.
jbrjake
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by jbrjake »

I didn't add user-accessible advanced x264 options so ignorant people would blindly play with them with no understanding of what they do. If you don't know which options work with what, you shouldn't be touching them. Period. That's why they're hidden away on an advanced tab, and why we have presets so ignorant people don't have to know what they're doing.

One-off contributions are *not helpful* since as I've explained in this thread already, the part that sucks -- the part no one involved in the project has any interest in doing -- is maintaining lists of device compatibilities over long periods of time.
Eliminating the need for each person that visits the forums from needing to ask this question, then go off and independantly discover the answer is a waste of a lot of people's time.
Total hyperbole. "Each person that visits the forums" is not asking this question. Not by far. This should have been clear to you, when you had to resurrect a *seven month old thread* just to make this absurd claim.
dynaflash
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by dynaflash »

You know, there is nothing stopping someone from doing the legwork and posting what they find in the forums. This is a community and anyone can contribute their knowledge for others to share. There is no reason it has to be a HandBrake dev or mod or whatever. Feel free to test settings and start a thread.

One other thing you should note on some settings. They may work on the atv given one source, but not work well on the next source. bframes is a good example. You can set bframes=9 and it is silky smooth on one source, but a bit jittery on the next source depending if x264 decides to to use more or less bframes. It's not always cut and dried.
jbrjake
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by jbrjake »

dynaflash wrote:You know, there is nothing stopping someone from doing the legwork and posting what they find in the forums.
Yep, that's the way to do it. Then it can be easily updated and tracked over time by anyone. Alas, that doesn't seem to be a good enough option for Terc.
Terc wrote:I would volunteer to help if my work would be posted outside the forums.
Terc
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by Terc »

I've obviously gotten off on the wrong foot here.

My comment about posting outside the forums was targeting the idea that it could be eventually added to a tinkerer's FAQ or something. I'll start a thread, and go from there.

I certainly appreciate the work everyone is doing here, I was frustrated last night because I had just run a series of encodes using 8x8 DCT and some had worked on my Apple TV, while others hadn't. I'm puzzled as to why any would have, it was a mistake that the first few encodes even ended up on my ATV, but when I saw that they were there, I headed here for some answers.

A post on this forum is absolutely good enough for me, I just want to ensure that other people will have less trouble finding these answers in the future.
One other thing you should note on some settings. They may work on the atv given one source, but not work well on the next source. bframes is a good example. You can set bframes=9 and it is silky smooth on one source, but a bit jittery on the next source depending if x264 decides to to use more or less bframes. It's not always cut and dried.
This is where I think I was having issues. I will investigate.
One thing that would help me get started is (preferably non-copywritten) material which will push specific bountries (b-frames for one, but in this example, 8x8DCT). I'm not sure exactly what motion types could trigger 8x8 DCT to break ATV compatability, especially when I have a few encodes using 8x8 DCT which worked, when another set was vetod by iTunes before syncing.
dynaflash
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by dynaflash »

Well, this thread http://forum.handbrake.fr/viewtopic.php?f=7&t=5129 cleverly entitled "ATV 2.x Advanced Settings (All Sources) will have some information you might be interested in.

As far as making it easy to find, just make sure your post has a descriptive title so it shows up in searches.
dynaflash
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by dynaflash »

Also you may have already noticed that hard data on what the ATV can handle is scant at best. Much of this is derived from empiricle testing. Compared to the iPod's the AppleTV is a bit of an enigma.
jbrjake
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by jbrjake »

Terc wrote:My comment about posting outside the forums was targeting the idea that it could be eventually added to a tinkerer's FAQ or something. I'll start a thread, and go from there.
A thread is better. The problem with putting it up on a web page is that we have to restrict access to the HandBrake web servers. No one has the time or energy to deal with the spam and duplicate tickets and edit wars an open Trac leads to. This means we can't take advantage of some of the strengths of having a wiki, like it being easy for the swarm to keep info up to date. So the burden of maintaining the info falls primarily on the devs.
I'm puzzled as to why any would have, it was a mistake that the first few encodes even ended up on my ATV.
8x8dct only gets applied when analyse=all. Was that on, on all of them? I'm puzzled as to why you were trying to do high profile output to the AppleTV in the first place. Dynaflash is right that a lot of the stuff is obscure for the device but if there's one thing that's clear it's that it's main profile only. You should be starting from the preset dynaflash crafted, and only adding to it when it makes sense, not globbing on every setting imaginable without reasoning it through.
One thing that would help me get started is (preferably non-copywritten) material which will push specific bountries (b-frames for one,
Just add no-b-adapt to your x264 opts, that will ensure the number of b-frames you set will be used constantly, instead of that being the maximum number of b-frames allowed in a row.
Terc
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Re: Advanced x264 Options - 8x8 DCT Compatibility

Post by Terc »

I was using analyze = all in all of the encodes I did, some worked, others did not. I will look into this over the weekend, possibly later. I'm currently finishing up work on my sr thesis and was only playing around last night (procrastinating).

Like I mentioned though, those encodes were not intended for my Apple TV, but after adding them to iTunes, I noticed some of them as available to stream to my Apple TV, tried them, and they (the videos that were available) worked. Obviously, more testing will be required to discover how that was possible.

Also, thanks for the no-b-adapt tip, I'll be using that tonight to test my current settings.
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