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Encoding question!

1058 Views 2 Replies 3 Participants Last post by  tchrin
I am going to attempt to encode a 3D movie to a more economical size in order to test the various devices I have, but I'm not sure what the answers to the following questions are...

First, the three playback methods that I am going to try and cater for:

1. Acer 5738DZG Laptop - Passive (theater glasses/polarised) - native res. 1366x768

2. Gadmei p83 PMP - Autostereoscopic (parallax barrier) - native res. 1280x768

3. LG Optimus 3D Phone - Autostereoscopic (parallax barrier) - native res. 800x480

Question number 1 - What is the effective resolution in 3D for the three machines (i.e. the picture each eye sees)? My guess is:

1. 1366x384 (halved vertical res. as it's interleaved, left eye seeing odd lines, right eye seeing even...)

2. 640x768 (halved horizontal res. as it is parallax barrier), and

3. 400x480 (halved horizontal res. as it is parallax barrier)

Question number 2 - Which method should be used for the two different types of screen (polarised and parallax)? Looking on the internet it seems that SBS should be used, but I'm not sure if that is ideal.

For instance, why not use Over/Under for the polarised screen with the top half of the signal being used ONLY for the odd lines for the left eye stream and the bottom half being used ONLY for the even lines of the right eye stream? As the polariser chucks out half of each stream when it sends the picture why not get rid of them to begin with and then at least you're seeing eveything that you've encoded?

For Parallax, I get that SBS would be best, for much the same reason (you are losing the horizontal res.)

Question number 3 - What res. should I use for the best picture (making use of native res.) for each of the screens? My guesses would be:

1. 1366x768 picture in SBS (or just plain 720p) would be the most straightforward, but I guess the answer ultimately depends on question 2 above... Maybe it should be Over/Under? If so, how do I get rid of alternate lines and the put the two streams together one on top of the other?

2. 1280x768 SBS (or should it be 1280x720 SBS, I'm not sure...)

3. 800x480 SBS

The reason I am asking all these questions, is because they don't really arise with 3DTVs, only with portable media players!! All help with understanding this is much appreciated!

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I have 2 and 3. You want to make 1280x720 sbs 1/2-frame videos using avc. These play beautifully on both devices. None of the "native" resolutions is 16:9, so you certainly do not want to make native resolution videos (there is no gain really from that). On the Optimus, I have played 108030p sbs videos perfectly as well, but they work less smoothly on the Gadmei.

You can stream 3D videos from Youtube to see how well the Optimus does playing 3D videos. Just link to any 3D Youtube video and the device will automatically play it in 3D. They look great.
Hi Markr

I have just bought the Gadmei last week, and can't play any 3D downloaded movie properly, for a matter of format. Which software would you recommend to use (Handbrake ??). I have no idea how to setup to 1/2 frame.

Thanks for your help

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