What's the max video resolution iPad can play back on screen?

[RoyalGalactic]

Originally Posted by whtrbt7

Doing the math for 4:3 video on an iPad screen is 2048 x 1563 x 24fps (conservative) x 2 x 0.07 = 10.755440 Mbps just for video. If we approximate audio at around 3Mbps, we're looking at a total of 13.76Mbps for the stream. That's a LOT of data.

Yeah, so far 8x5 is the most I've gotten to play at 2k on the iPad. I'm rendering a 16x11 clip right now...we'll see how it looks.

4x3 plays but the bitrate has to be so low that it looks terrible.

[whtrbt7]

Originally Posted by RoyalGalactic

Yeah, so far 8x5 is the most I've gotten to play at 2k on the iPad. I'm rendering a 16x11 clip right now...we'll see how it looks.

4x3 plays but the bitrate has to be so low that it looks terrible.

Ah yeah, true. What do you suspect the maximum bitrate we can churn on the PowerVR chips is? 16x9 should work better. Fingers crossed you get 16x11 to look decent. I think the problem with the graphics right now is due to the memory controllers they are using on the PowerVR chip. I'm no GPU expert but it looks like there's a bottleneck happening at the mem controllers.

[RoyalGalactic]

My gut feeling is the iPad is optimized for up to 1920. It has the raw horespower to play 2048 but in messing around with bitrates and resolutions it feels like Apple could get the iPad to play full 4x3 22Mbit/s video if it wanted to. I'm hoping a future iOS release will do exactly that because even 2048x1080 looks freaking amazing.

[Redjericho]

Originally Posted by whtrbt7

Not a great analogy. Here's one that may make more sense. It's like making an engine that goes up to 160mph but only driving at 80mph max.

Also not a great analogy, its like saying the ipad has the ability to handle large resolution videos, we just choose to use low res videos, here's a combination...

Having a car that is capable of going 160mph but having an engine can only handle up to 80.

Car = retina display/iPad
Engine=GPU

[RoyalGalactic]

Originally Posted by Redjericho

Also not a great analogy, its like saying the ipad has the ability to handle large resolution videos, we just choose to use low res videos

Actually whtrbt7's is pretty accurate...I just rendered a 2048x1408 clip and it looks amazing on the iPad. Will be uploading shortly. Well, in 2 hours 35 mins hehe.

[RoyalGalactic]

Wow, check this one out: 16x11 or 2048x1408. http://www.camerarentalz.com/video/retina-16x11.mov

Instructions here: http://camerarentalz.com/2048-video-ipad-retina/

[Redjericho]

Originally Posted by RoyalGalactic

Wow, check this one out: 16x11 or 2048x1408. http://www.camerarentalz.com/video/retina-16x11.mov

Instructions here: http://camerarentalz.com/2048-video-ipad-retina/

Lol! I tryed doing the steps (goodreader method) except on my iPad 1 and it flashed blue then instantly caused by entire device to reboot.

[RoyalGalactic]

That's what happens when I try to load a full 2k 4x3 file! It's really weird...I can get really close to filling up the whole retina screen but as soon as I get to 1536 it looks really crappy and crashes my iPad.

This is my latest render, 2048x1463, only 73 pixels less than the full retina screen...and it plays great! http://www.camerarentalz.com/video/retina-16x11.5.mov

[Maven1975]

Originally Posted by RoyalGalactic

That's what happens when I try to load a full 2k 4x3 file! It's really weird...I can get really close to filling up the whole retina screen but as soon as I get to 1536 it looks really crappy and crashes my iPad.

This is my latest render, 2048x1463, only 73 pixels less than the full retina screen...and it plays great! http://www.camerarentalz.com/video/retina-16x11.5.mov

Stunning! Great work.

[gatortpk]

Originally Posted by gatortpk

I downloaded a few 4K video samples from YouTube and I am now re-encoding them to 2048x1536. Some of the 4K video is actually only 1714p (2.39:1 ratio). So I lost less than 11% of the vertical resolution, kept the aspect ratio and cropped around 916 pixels off the sides. The resulting video is 4:3 ratio, but shows almost the full vertical resolution of the original. I'll see if the iPad will play the "normal" profile (as opposed to high profile) 1536p video...

Edit: iTunes will not sync the 1536p video because "it cannot be played on this iPad". I am now re-encoding the video to 2560x1080p, 1920x1080p, and 1920x800p (original aspect ratio). I'll see if 1080p is the limitation or if 1920 horizontal pixels is the limitation. Hopefully I'll be able to sync the 2560x1080p video.

I'm updating finally, (got around to some free time), I had that 4K video re-encoded to 2048x1536 and 1920x1536 as well as a few other resolutions.

I used Dropbox to transfer the videos (then used AwesomeFiles to play back because DropBox kept the top bar with the "iPad / Time / Battery icon" during playback). I found that the Full HD 1920x1080 worked fine obviously, but the 2048x1536 didn't, not surprised by that, after reading these earlier posts.

However, the 1920x1536 did play perfectly! Playback with both Dropbox and AweSome files, and not even a hint of stutter or lag. The 2560x1080p encoding didn't work either, which was unexpected since 1920x1536p did. I figured the fewer pixels total, the more likely the playback, but 2560x1080 (2.73 MP, does not play) has fewer pixels than 1920x1536 (2.95 MP, does play). I assumed that the vertical resolution of 1080p would be more limiting than the horizontal resolution of 1920.

Apparently the horizontal resolution is more important than the vertical resolution when exceeding 1920x1080. So shaving off an extra 64 pixels off each side enables 1536p playback of an original 4096x1714p movie trailer re-encoded to 2048x1536.

Does anyone know if this is a overlooked software limitation OR a hardware limitation. (I haven't had any crashing, or bouncing back to the springboard, just DropBox shows nothing, and AwesomeFiles returns to the file list. But both Apps play the 1920x1536p movie trailer fine).

[sekazi]

Originally Posted by whtrbt7

Doing the math for 4:3 video on an iPad screen is 2048 x 1563 x 24fps (conservative) x 2 x 0.07 = 10.755440 Mbps just for video. If we approximate audio at around 3Mbps, we're looking at a total of 13.76Mbps for the stream. That's a LOT of data. It's hard enough to pump that amount of video through the Intel HD 3000 chipsets, a quad core mobile chipset would probably do much less.

Not a lot of data according to the iPad





92.4 mbps. Playback is fine on the iPad

[gatortpk]

Originally Posted by gatortpk

Apparently the horizontal resolution is more important than the vertical resolution when exceeding 1920x1080. So shaving off an extra 64 pixels off each side enables 1536p playback of an original 4096x1714p movie trailer re-encoded to 2048x1536.

I was talking about the "Lord of the Rings" 4K Super Trailer, I re-encoded it to 1920x1536 and it plays perfectly. The original file is 4096x1714. I just compressed it to 1536 lines (90% of the full vertical resolution) and truncated about a quarter off the sides (24% off each side).

As I said before, the 2048x1536 didn't play at all on any App, but the 1920x1536 plays fine on the new iPad.

Does anyone have a suggestion to where I can post this video for anyone else to try out? (Or would this not be a good idea due to legal reasons? It's a movie trailer, an advertisement for the trilogy themselves. Are they not accepted to post?)

[RoyalGalactic]

You can actually get full 2048x1536 video to play on the iPad by encoding it anamorphic and tricking the iPad into thinking it is lower rez. I will post an example shortly. My buddy Bill Barnes discovered this method and it looks amazing.

[b.c.]

Originally Posted by RoyalGalactic

This is my latest render, 2048x1463, only 73 pixels less than the full retina screen...and it plays great! http://www.camerarentalz.com/video/retina-16x11.5.mov

this is great work, just downloaded and viewed this using GoodReader and it looks fantastic. keep us posted!

[Menneisyys2]

Originally Posted by noshjewman

There are other video players - like OPlayer and FlexPlayer - that might work. I use VLC - but it's no longer available.
I haven't tried using a format larger than 1080p though, let me know if any of these work!

Don't use VLC, it's one of the worst players - it doesn't even use hardware decoding for H.264 MP4 / MOV files. Almost all the other players are considerably better and more powerful.

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Originally Posted by whtrbt7

Ah yeah, true. What do you suspect the maximum bitrate we can churn on the PowerVR chips is?

It has no problems playing back 40 Mbps very quickly scrolling 1080p videos like the one at http://www.auby.no/files/video_tests...mbps_birds.mkv . That's a direct, non-transcoded BD rip! (Needs to be demuxed to MP4 via avidemux2 so that the hardware decoder accepts it.)

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Originally Posted by gatortpk

Does anyone have a suggestion to where I can post this video for anyone else to try out? (Or would this not be a good idea due to legal reasons? It's a movie trailer, an advertisement for the trilogy themselves. Are they not accepted to post?)

I don't think posting ads (=movie trailers) to, say, DropBox is illegal. After all, they're meant for spreading

[maxboy]

[/COLOR]

It has no problems playing back 40 Mbps very quickly scrolling 1080p videos like the one at http://www.auby.no/files/video_tests...mbps_birds.mkv . That's a direct, non-transcoded BD rip! (Needs to be demuxed to MP4 via avidemux2 so that the hardware decoder accepts it.)[COLOR="#808080"]

Wow, i thought the max bitrate it would take is 6Mbps since anything above it can't be sync through itune.(tried with Media espresso, H264, 1080p)

[RoyalGalactic]

I have been able to get 2048 60Mbits/s to play smoothly on the iPad 3...it is shockingly powerful when it comes to high-res video.

[Menneisyys2]

BTW, I'm just playing with 2k videos... will post a LOT of new info soon!

[gatortpk]

Originally Posted by RoyalGalactic

You can actually get full 2048x1536 video to play on the iPad by encoding it anamorphic and tricking the iPad into thinking it is lower rez. I will post an example shortly. My buddy Bill Barnes discovered this method and it looks amazing.

That's a good point!

Here's the Lord of the Rings Super Trailer re-encoded from a 4K (4096x1692) source to 1920x1536p. It plays on "Awesome Files" and "DropBox" Apps fine on my iPad. This is not anamorphically stretched to 2048x1536, but that wouldn't add to the actual resolution of 1920x1536 anyway, may be better off using the "fill screen" option/button at the right of the play bar.

https://www.dropbox.com/s/zf2724w6k0...morphic%29.mp4

(As I have said earlier, I tried the 2048x1536 version of this trailer, and it wouldn't play on any app.)

[Menneisyys2]

Originally Posted by gatortpk

This is not anamorphically stretched to 2048x1536, but that wouldn't add to the actual resolution of 1920x1536 anyway, may be better off using the "fill screen" option/button at the right of the play bar.

Yup, the anamorphic encoding mode is fully useless. I've made some serious resolution and power consumption tests (will publish the results this night) and found out that there is no point in encoding to H.264 for anamorphic playback.

EDIT: Let me correct myself: by "Yup, the anamorphic encoding mode is fully useless." I meant for Full HD and not for 2k+. See my just-published article for more info.

[RoyalGalactic]

Originally Posted by Menneisyys2

(Are only actual RED users allowed to post there? That'd be a bummer because I could contribute a lot to the discussion there...)

Anybody can post on REDuser...you do have to sign up with your real name though: http://www.reduser.net/forum/showthr...432-Real-names

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Great post Menneisyys2!

I am going to render out some H.264s using the anamorphic method shortly...it's just a lot more time consuming because I haven't found a way to do this straight out of an NLE like Adobe Premiere. I have to render to an intermediate file and than do the anamorphic part in Handbrake. Bill Barnes is working on a Premiere plugin that will hopefully make all of this super easy.

[gatortpk]

Originally Posted by Menneisyys2

OK guys, my new article has just been published!! http://www.iphonelife.com/blog/87/ne...ack-definitely

Nice article!

I'll have to follow some of those suggestions (and read the article again). I too have an exact 1080p Avatar BD copy. Even though the vertical resolution isn't as high as the 1692p Lord of the Rings trailer I used, the quality is clearly higher, a much higher bit-rate and quality encoding was used. Plus, it doesn't have any grainy "film" look to it. (And it didn't go through YouTube, even though the trailer was 4K)

I re-encoded Avatar to 11.7 GB and only 9.65 Mbps, but I could hardly tell the difference. (Any suggestions to where I can do an A-B comparison of the two copies of the video to really see the difference between the original and the 9.65 Mbps re-encode? I have a 27" iMac with a vertically attached 1080p display, i.e. 1080x1920p.)

I'd like to really enjoy watching Avatar with a near studio quality display (for color and contrast ratio accuracy) as reported at DisplayMate.com.

[Menneisyys2]

Originally Posted by gatortpk

I re-encoded Avatar to 11.7 GB and only 9.65 Mbps, but I could hardly tell the difference. (Any suggestions to where I can do an A-B comparison of the two copies of the video to really see the difference between the original and the 9.65 Mbps re-encode? I have a 27" iMac with a vertically attached 1080p display, i.e. 1080x1920p.)

With "natural" images, it's a bit harder than with "synthetic" ones (like rescharts) I use in my tests. Look at finely-detailed parts, most importantly, grass, leaves and the like.


However, if you take two framegrabs of exactly the same shot, they can even be compared by tools like Photoshop (see the section in my article on difference image creating in PS. If you don't have PS, just post the two grabs here and I create a difference image for you.)

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Originally Posted by RoyalGalactic

Anybody can post on REDuser...you do have to sign up with your real name though: http://www.reduser.net/forum/showthr...432-Real-names[COLOR="#808080"]

Thanks! That was the problem. I'll re-do my registration.

[gatortpk]

Originally Posted by Menneisyys2

With "natural" images, it's a bit harder than with "synthetic" ones (like rescharts) I use in my tests. Look at finely-detailed parts, most importantly, grass, leaves and the like.


However, if you take two framegrabs of exactly the same shot, they can even be compared by tools like Photoshop (see the section in my article on difference image creating in PS. If you don't have PS, just post the two grabs here and I create a difference image for you.)

Thanks for the suggestions. With Photoshop and two exact same frames from each video, do you mean doing something like difference blending, is that the same as subtracting one image from another, resulting in nothing more than an image with pixels that represent different values from each of the two (nearly) identical frames?

I can see how that would show exactly where there are more compression artifacts that show up in one frame compared to the original. But the video itself has temporal compression. Would the exact frame (same 1/24th second part of the whole movie) be identical except for the increased compression, or would their be temporal artifacts?

I noticed that Handbrake has "Same as Original" for frame rate, and that it could be a variable frame rate. I'm not sure why there is a variable frame rate feature, unless it's a (new to me) form of video compression that takes really does skip frames if they are similar enough? If that's the case, two exact frames from different videos may show quite a bit more difference than the increased compression artifacts, (than would occur if each frame were compressed individually and independently. I know none of the mpeg compressions do, they are all temporal compressions, not for lossless or non-linear editing)

[Menneisyys2]

Originally Posted by gatortpk

I can see how that would show exactly where there are more compression artifacts that show up in one frame compared to the original. But the video itself has temporal compression. Would the exact frame (same 1/24th second part of the whole movie) be identical except for the increased compression, or would their be temporal artifacts?

Compression artifacts (blocking etc.) are well visible in framegrabs too. If the encoder is lousy OR the bitrate is far too low, fast-moving scenes can exhibit horrible "breakdowns", in addition. (For example, Pana's older P&S 720p cameras have such an encoder - if you pan the camera fast while recording 720p, the image breaks down and only recovers after about 0.5s. No such problems with more recent coders like the one in the iPhone 4/4S, not even at the same or significantly lower bitrate.)