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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

"new Ipad" (3) , how do I get highest quality demo video on it ?

Andrew M. said:
This is very good question, instruction just mentioned "to connect your iPad to the HDMI TV"
But I have seen iPad playing laptop screen content replicated by AirPlay I think.

There is a way to show computer screen content on iPad, try google. I came across an article how to do it.
Click to expand...

Found it. Company called Teradek. $2K each for transmitter and receiver using SDI and with 1/4 second lag. Hardly worthwhile until it becomes cheaper and/or closer to real-time.
 
Carl Elster said:
There is an app with accompanying free program that will make your iPad into a second monitor. There is no delay and it works quite well!

http://avatron.com/apps/air-display

I sincerely doubt it has 2k capability....
Click to expand...

That is cool in its own right but I'm thinking of ways to use the iPad as a client monitor during production. Without having to go through a computer :)
 
I have been searching or one as well and from what I've found the Teradek cube is the best solution available right now for under $10, 000. A DOP friend of mine said that with the new firmware on the Teradek the delay is even less. She was very impressed by the Teradek and said it works well and was easy to setup etc.

I'm looking forward to a hands on demo myself.
 
Same thing here, something wrong with export.
Similar effect as the TimeScapes.
Maybe you have to check all export parameters?

Looks like you exported it without the speed limit.
TimeScapes is also exported without the speed limit.
Rerender this file putting restriction on the stream speed.

update:

I loaded retina-h264-32Mbit.mp4 on my laptop into the QT player.
Both this file and TimeScapes do not show streaming limit, yet you mentioned that you set it to 32MBits/sec.

Maybe mp4 .files on the QT do not show the limits?
.mov files all show limits if exported this way.
You can see it on QT in the movie inspector.
This one do not show.

I loaded file into local iPad memory.
Opened it in iPad player, it tries to start, blank screen for a second and quits immediately.


Justin O'Neill said:
I rendered out a 2048 32Mbit/s H.264 clip with Premiere: http://dl.dropbox.com/u/5673574/retina-h264-32Mbit.mp4

Won't even load on my iPad...
Click to expand...
 
This is a great thread and a topic I’m really interested in. Up until now I think my posts have been a bit off-the-cuff and non-rigorous; sorry ‘bout that. I’m going to try to offer more evidence this time. Any criticism is appreciated.

Short Version:

All the following videos are encoded with Handbrake on OSX and work on the iPad3 via Dropbox, GoodReader and CineXPlayer.

TIFF 2048x1536 Test Pattern Image

PNG 2048x1536 Test Pattern Image Screenshot
This is a screenshot of the TIFF taken on the iPad3. I include this because screenshots taken by the iPad3 have a slight color shift. I will use this file for comparisons with screenshots taken from the videos.

H.264 2048x1536 Test Pattern Video

H.264 1920x1440 Test Pattern Video

MPEG4 2048x1536 Test Pattern Video

For fun:
Timescapes Trailer – H.264 2048x1152 40Mbit High Profile - encoded from Tom’s 2560x1440 file

Long Version:

I started out with the test pattern JPG I found with Google, resized it in Photoshop using Bicubic Sharper to 2048x1536, output a TIFF, and dropped it into Final Cut 6. I created a 10 second sequence and output it uncompressed at 2048x1536 resolution. It’s a 3 gig 10 second video.

From there I created a 1920x1440 (4:3) resolution H.264 video and took a screenshot with the video paused. Comparing this to the PNG Chart in Photoshop produced this difference image:

H.264 1920x1440 vs chart screenshot

Next I made an MPEG4 2048x1536 version of the video. Compared to the PNG Chart, Photoshop produced this difference image:

MPEG4 2048x1536 vs chart screenshot

After some research I made a special H.264 encode at 2048x1536. Compared to the PNG Chart, Photoshop produced this difference image:

H.264 2048x1536 vs chart screenshot

Finally, I compared the MPEG4 2048 image to the H.264 2048 image:

H.264 2048x1536 vs Mpeg4 2048x1536

In the difference images the darker areas are very similar and the brighter areas are very different. Here’s a Photoshop file with all the images lined up and labled. Pick any 2 layers to compare them:

Photoshop file

Based on these tests, MPEG4 at 2048 does a better job than H.264 at 1920 at holding detail. This doesn’t mean it’s better in motion, holds color better, or better per megabyte, but I think this makes a good argument that the detail lost from the small upscale of 1920 video is significant. MPEG4 at 2048 wins here in my opinion.

However H.264 at 2048 vs MPEG4 at 2048 produces very, very few differences which is important since my way of getting H.264 on the iPad3 at 2048 resolution is a slight hack. I think it’s fair to say that if it works, the detail in the H.264 file is “as good as MPEG4” resolution-wise and we get all the benefits of the H.264 codec.


My Solution:

So here’s how you do it: H.264 supports anamorphic encoding of an arbitrary amount.

My H.264 files are encoded at 1920x1536 in anamorphic mode with a horizontal stretch of 1.0666666. It outputs as 2048x1536 and this is taken care of by the encoder which should prevent the iPad3 from needing to use its hardware scaler. It took some digging but the option is right there in Handbrake. (I have no idea what other encoders expose this option, but Handbrake is a cross platform front-end for FFMPEG and is free.)

Handbrake settings Screenshot

Open the file you want to encode, choose an output name, then select High Profile under the Presets windows / Regular Settings.

Hit the picture settings button at the top (Mac Version) set “Anamorphic” to custom, Set your “width” to 1920, then reduce the “height” until “screen resolution” says 2048.

Set your audio and any other settings the way you like and hit the start button at the top to encode.

I think this is a good workaround for what really should be a temporary shortcoming of the iPad3’s software. Normal 2048 H.264 encoding should be allowed at some point and that should provide the best results.

Hope this helps,

Bill
 
Justin testing to see how much of the vertical we can fill...here is an 8x5 clip or 2048x1280. Looks amazing! http://dl.dropbox.com/u/5673574/retina-8x5.mov

Btw, Bill is a genius, his H.264 workaround WORKS! Now I have to download and learn handbrake.
 
Bill, thank you very much for all the tests.
Looks like perfect solution for now.

Bill, did you try to see if 1.0666 upres do preserves all the lines in the every second pixel pattern?
I squeezed 2048 to 1920 on the 65” Bravia and I got Moire.
I guess it is the same other way around.

Justin, yes I am downloading your files to desktop.
I have DropBox on the PC and on iPad.
I drop the files from the desktop to DropBox
Wait till green check mark is checked. (means all uploaded to DropBox)
Take the iPad click on the DropBox and files are there.

BTW iPad is recording from its own on board camera at 22MBits/sec playing limit and produces .mov file.
 
Hey Andrew,

When I compared the 2k MPEG4 image to the 2k(1920 anamorphic)H.264 image I it looked like this.

Pretty close to pure black. What I gather from this is the 2k MPEG4 video is no better than my 2k H.264 video. This is the image where I would expect to see Moire if it exists. It looks pretty good (not 100%, but close) to me. I think a large part of it's ability to retain quality is due to the encoder knowing from the beginning that it's supposed to display 2048 video, so it can plan accordingly.
 
What was the source you were producing these two files from?

BTW TimeScapes reencoded to 2048 plays perfect, smooth like silk.
Hey! 681MB file for 2:18 seconds at 40.2 MBits/sec is probably maximum what iPad3 can take in H.264.

I try to run one single application in the background while playing and I could see it started to drop some frames.
Also playing it from DropBox you can forget it, you have to download it to the iPad memory.
I was using Air Sharing to do it.

So high performance clips we can go all the way to 50MBits/sec but to be in mass distribution for iPad3 I will stay at 22MBits/sec hard limit.
Never leave speed unlimited while encoding, at 2K you are asking for trouble.
 
BillBarnes said:
Hey Andrew,

When I compared the 2k MPEG4 image to the 2k(1920 anamorphic)H.264 image I it looked like this.

Pretty close to pure black.
Click to expand...

Bill, not really black, turn up exposure in PS by 8 or so, plenty of pixels showing up.
However value of the pixel is 1/255 so I think it will not make much difference.
Human eye can recognize only 6 stops so 8 stops difference on gray probably will not be visible.
 
Hello,

I am joining the party a bit late...

Just experimented to arrive at a preset for Squeeze in 1080p, 35Mbits, performance 16, 4.1 profile, CAVLC, multipass, 35Mbit VBR limit, no HRD conformance, Fixed I frame distance, Adaptive B-frame placement.
Encode from ProRez4444 is quite stunning and plays smooth.


Could someone help me with the 2K? (player, file transfer, encoder, bitrates...)
I am a bit lost in the latest results of this fabulous thread.


Thank you.
 
It depends what do you want to use iPad3 for?

Just to play clips use 2048 H.264 and limit the speed to 40 MBits/sec
If you want to stream it to you screen over WiFi stay below 20MBits/sec

AirPlay or Apple TV box will not take 40MB/sec at 2048 real time, it will start and stop but it will play full res 2048 cropped to 1920 with full details.
 
Any chance someone out there can feed this zombie thread fresh info?

Goal is an H.264 encode for iPad with no scaling artifacts, accessed via Dropbox or similar.

Source frame size of 1920 x 1080.

Has anyone tried just adding 64 pixel wide black pillars on each side then re-encoding? If so, what was the result?

Anyone care to tout a particular encoder as superior?

Cheers - #19
 
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