1920x1080 on ATV2

[Scott R]

I recently ran a bunch of tests trying to figure out the magic formula/compromise for getting my Blu-ray movies ripped/converted to 720p MP4 files that a stock AppleTV 2 could play. After doing all of that, I figured just for fun I'd convert a movie using the AppleTV 2 preset, but changing the resolution from a resolution of 1280 to 1920. I expected that XBMC on the ATV2 would be able to handily play it (based on my experience with XBMC successfully playing many of my 1080p MKV Blu-ray rips smoothly), and I've been debating whether I should convert to 1080p so that I can be "ready" for the next A5-based ATV, if Apple ever releases such a thing. Plus, I've got a couple of Acer Revo's that could be connected to my 1080p displays (right now I just have one 1080p display), and I'd be getting the maximum advantage there. The big negative for me was that the files would play very badly on the stock ATV, and I'd kind of like to possibly eventually stick with the stock UI, rather than dealing with jailbreaking and the somewhat more complicated XBMC UI.

So as I started off saying, I went ahead and ripped 10 minutes of The Incredibles at 1920x1080 (or whatever the actual resolution was, once you take into account the extra black bars on this film) using the AppleTV 2 preset (RF 20). Then I went to play it via the stock ATV2 UI. At first it seemed a bit stuttery, which was consistent with my experience way back when the ATV2 first came out. But then it seemed to clear up. I'm thinking that perhaps it was more stuttery while it was still transferring the movie over to the buffer? Once the buffer was filled (remember, this was just a 10 minute clip), I skipped back to the beginning and played it again. It seemed smoother than before, but there did seem to be a few dropped frames. But, again, after that it seemed to be much smoother, perhaps even perfectly smooth. I think i might have spotted a few more dropped frames later on, but it definitely didn't seem to be a common thing. At the end of it all, I was thinking that this might actually be workable. I'm easily bothered by these things, but I'd rate it as follows: If I was watching a movie like this in my living room (720p TV farther away), I probably wouldn't be bothered by it. If I was watching it in my bedroom (52" 1080p TV fairly close) or in my loft (720p front projector), I might want to play it thru XBMC or my Revo, just to keep it perfectly smooth. But I suspect that my wife/daughter/siblings/friends probably wouldn't notice the few dropped frames.

Has anyone else tried this? And to the developers/experts: are there any tweaks to the Apple TV 2 preset that we could make that would tax the ATV2's A4 less, so as to make it even smoother (e.g., reducing bitrate a little bit, but not so much so as to noticeably impact PQ)?

I'm also tempted to let my one non-jailbroken ATV2 perform a firmware update, just in case Apple might have slipped in some undocumented performance tweaks with the recent update.

[Deleted User 11865]

The Incredibles may not be a cartoon, but it's still animated content. Not exactly the ideal source for stress testing - if you want to create a "set and forget" 1080p preset for the ATV 2, you're going to have to test it with "difficult" sources. Have you tried something like the birds scene in Planet Earth?

[JohnAStebbins]

Several people tried all manner of 1080p settings variations when the ATV2 first came out. No matter how much they dumbed down the settings, there was always some stutter. I'm only making an educated guess here, but my guess is that it's inability to play 1080p smoothly isn't due to any limitation with it's h.264 decoder. Instead, I think it may be a bus bandwidth limitation. It just can't pump decompressed 1080p images through it's scaler (to downscale to 720p since that's all it supports for output) without bottlenecking a memory bus.

[Scott R]

Have you tried something like the birds scene in Planet Earth?

I tracked that down and tried it last night. I first tried the full-bitrate .mkv file via XBMC on the ATV2. It was a super choppy mess. Then I converted it, using the ATV2 preset on Handbrake, to both a 720p and 1080p MP4 file. Both clips seemed to play OK, but the 1080p version did seem to have a few dropped frames. It was hard to say for certain because the clip is fairly short and there's no way to bring up an on-screen indicator of how many frames are being dropped. XBMC has the ability to display that sort of info, though I'm not sure if there's a way to do it on the ATV2 build of XBMC, but that wouldn't be informative anyway, since I know that XBMC can play some high-bitrate 1080p content smoothly.

I then went back to my Iron Man test segment, and converted that to 1080p. That appeared to have some definite "smoothness" issues. That's probably the best way to describe it. It seemed like it was playing the movie at 20fps, or some less-than-24fps, but constant, number.

I'm only making an educated guess here, but my guess is that it's inability to play 1080p smoothly isn't due to any limitation with it's h.264 decoder. Instead, I think it may be a bus bandwidth limitation. It just can't pump decompressed 1080p images through it's scaler (to downscale to 720p since that's all it supports for output) without bottlenecking a memory bus.

But just to be clear, XBMC on the ATV2 *can* play 1080p content (720p output) smoothly. So, the hardware is certainly capable of it. The limitation is with Apple's software decoder. Note that from what I understand (per an XBMC dev), the hardware is *not* capable of ever accomplishing 1080p output, with the inadequate video RAM being one (or perhaps the only) reason for that (i.e., as I understand it, the A4 CPU may not be the bottleneck).

On a slightly related note...I watched a movie last night in our master bedroom which has a 52" 1080p LCD about 10 feet away. The movie we watched was an old standard-def DVD .ISO rip (we watched it through XBMC on the ATV2). I had my glasses on, so my vision was 20/20. Initially I was hesitant to watch it because I had been messing around with encoding HD samples the past couple of days and was thinking I'd be really disappointed/distracted by the crappy old low-res picture. Instead, I was immediately thinking, "this looks surprisingly good." YMMV, but the moral of the story is that a good movie gets you involved and you tend to stop thinking about the PQ pretty easily. I do believe that HD enhances the experience, but it's harder to put my finger on that. I've watched many HD movies where I'm immediately impressed by the sharpness, color vibrancy, and lack of noise during the opening logo, but after 15 minutes I'm just "watching the movie" and only occasionally do I get "distracted" from the story by the added resolution/detail jumping out at me in a scene and thinking, "wow, this level of detail wouldn't be possible with the standard-def DVD." Where I'm going with all of this is that I would probably be doing myself a favor by "moving on" from this quest to achieve smooth 1080p, and just decide that I'm going to rip my movies down to stock ATV2-compatible 720p files, as the result will still be a really nice upgrade from standard-def DVD.

...but can I resist the urge to want to try to get 1080p working? So back to my original question...before I give up on this entirely, are there some particular settings that I could try within Handbrake that would result in a 1080p file that might be more "easily" digested by the stock ATV2?

[AugieMendoza]

I too started looking ahead to the rumors of the next gen Apple TV and I started experimenting with some of my BR movies to see what would and what wouldn't work. Initially I started with my favorite movie Forrest Gump and used the High Profile setting (Which is the one I currently use only changing the resolution width to 1280, all working perfectly fine). The encode was a mess in various parts trying to stream to the ATV2 over both gigabit ethernet and wi-fi. After playing it through VLC and Plex on my Mac I noticed in certain parts the bitrate would spike up to about 13-18 mbps. The Vietnam scene when the helicopter is about to land just crapped out my ATV2. So I encoded it again but this time I figured I would control those spikes but adding...

:vbv-maxrate=9500:vbv-bufsize=9500

... to the end of the x264 advanced settings. Surprisingly, this encode streamed perfectly on the ATV2, iPhone 4, and iPad 2. All on wi-fi. I didn't notice many dropped frames if any at all, but like you said once you're into the movie the quality is not on your mind anymore. I also played the 1080p file from my iPad 2 to my 1080p HDTV using the HDMI adapter and that looked amazing. While my 720p version looked great before, 1080p was even better! Anyways, I hope this helped you out and I really do hope Apple comes out with a new AppleTV with the A5 processor to handle the 1080p goodness.

[Scott R]

Augie, that's the sort of information I was hoping for, but I'm having trouble believing it will work (though I'll certainly try it anyway), as I tracked down the necessary tweak to allow me to display the on-screen performance information with the Apple TV remote, and when I played my existing 1080p test clip, the Mb/s meter was showing the first couple of minutes of it as being under 9 anyway. In XBMC it's playing smoothly, but when I pop back over to the stock ATV UI and play the clip, it plays as though it's only about 20fps. Again, I'll plug in your settings and encode it again just to see what happens, but if I'm reading the right meter, it doesn't seem like that's the problem with my file. I'll add, lastly, that I've been using the ATV2 preset as my starting point, whereas you mentioned using the High Profile setting, so I'll try to mirror your settings more precisely with this next test.

[AugieMendoza]

I'm curious to see how you're encode comes out. Try adding the settings I gave with both the High Profile and ATV2 presets. Let me know how it turns out.

[Scott R]

Just wanted to report back with a quick update. The tweaks you suggested combined with the High Profile setting didn't work well for me. This still stuttered on my ATV2 (though it seemed more like frequent dropped frames at an irregular rate, whereas the settings I had used previously looked more like a constant decreased framerate (i.e., like a steady 20fps).

I did another encode which combined your tweaks with the ATV2 preset, but haven't had a chance to play that yet (my wife was hogging the monitor in the desktop which I needed access to in order to add the movie clip to my iTunes server).

I'll report back on that, but I can pretty much guarantee that the results won't be good based on some other findings of mine last night. I encoded Iron Man using the ATV2 720p settings (with the standard RF 20 setting) combined with the "Veryfast" settings documented elsewhere in the forums. This resulted in a nice, fast encode, but when I went to watch it last night I was hit with several early scenes with really bad blockiness. These were very dark scenes (in the cave) which I believe is a common encoding headache. So today I encoded numerous other test rips just trying to get that right. I found myself needing to go down to at least RF 16 with no "fast" tweaks, before I felt like I could be happy with the end result. Using RF 16 also meant a larger filesize. So I'm now thinking that a 1080p encode, if I could get it to play on a stock ATV2, would likely require a very high-quality RF setting and, thus, a very large filesize.

[potatis]

Sorry for some newbie questions but I have yet to buy and iPad 2 or ATV2.
Although I wonder is there any difference in playing 1080p files on iPad 2
via Airplay and via the HDMI-cable Apple sells? Would it be the same stutter?

Is there any "iPad 2 preset" you can recommend with the ATV2 preset as base,
that will make 1080p files guaranteed to play, with HDMI-cable and Airplay?