Non-standard anamorphic PAR conversion

TwoToad · 30th April 2010, 03:58

Basically, I am trying to encode an anamorphic 720x480 DVD to 640x480, and then apply a PAR in Yamb to stretch it back to 853x480.

The reason I am trying to do this is because I am trying to emulate what Apple does in iTunes in order to maintain as much resolution as I can.

I looked at a few purchased downloads from iTunes in MediaInfo and noticed that they are 640x480 with a Display Aspect Ratio of 16:9. I understand the 640x480 video is to maintain compatibility with the older iPod 5.5G models. What I don't understand is how they stretch it back to a 16:9.

When I encode the video, should I be adding a --sar ?:? to the x264 command line. Or in Yamb, when I remux, should I add a custom Pixel Aspect Ration of ?:?. Or should I be doing both?

What is the formula to get the ?:? part that I am looking for, for regular 16/9? What if I had a 2.35:1 video? I am having a hard time understanding this, so any help is appreciated!

Inspector.Gadget · 30th April 2010, 04:16

Are you shooting for iPod compatibility or something? If not, this is decidedly suboptimal.

TwoToad · 30th April 2010, 06:15

Yes, I am going for iPod 5.5G compatibility, and this appears to be how Apple manages it. I was going to encode a dvd or two to see how they turned out. It may prove to not be compatible at all, or only with the iPod and nothing else.

I guess my ultimate goal is to store my dvd's on an external and have them be compatible with iPod, Touch, and PS3. I was using the lowest common denominator between all those devices (640x480 but can handle anamorphic), but at the same time, maximize the quality (or resolution). My normal route has been to encode at 640x432, then stretch back to 16/9 resulting in a 787x432 video. I was going to try to improve this a bit from 432p to 480p.

When you say suboptimal, what do you mean? I'm not sure how Apple handles it and still produce good videos from their store.

30th April 2010, 03:58	#1 \| Link
TwoToad Registered User Join Date: Oct 2005 Posts: 76	Non-standard anamorphic PAR conversion Basically, I am trying to encode an anamorphic 720x480 DVD to 640x480, and then apply a PAR in Yamb to stretch it back to 853x480. The reason I am trying to do this is because I am trying to emulate what Apple does in iTunes in order to maintain as much resolution as I can. I looked at a few purchased downloads from iTunes in MediaInfo and noticed that they are 640x480 with a Display Aspect Ratio of 16:9. I understand the 640x480 video is to maintain compatibility with the older iPod 5.5G models. What I don't understand is how they stretch it back to a 16:9. When I encode the video, should I be adding a --sar ?:? to the x264 command line. Or in Yamb, when I remux, should I add a custom Pixel Aspect Ration of ?:?. Or should I be doing both? What is the formula to get the ?:? part that I am looking for, for regular 16/9? What if I had a 2.35:1 video? I am having a hard time understanding this, so any help is appreciated!

30th April 2010, 04:16	#2 \| Link
Inspector.Gadget Registered User Join Date: May 2008 Posts: 1,618	Are you shooting for iPod compatibility or something? If not, this is decidedly suboptimal.

30th April 2010, 06:15	#3 \| Link
TwoToad Registered User Join Date: Oct 2005 Posts: 76	Yes, I am going for iPod 5.5G compatibility, and this appears to be how Apple manages it. I was going to encode a dvd or two to see how they turned out. It may prove to not be compatible at all, or only with the iPod and nothing else. I guess my ultimate goal is to store my dvd's on an external and have them be compatible with iPod, Touch, and PS3. I was using the lowest common denominator between all those devices (640x480 but can handle anamorphic), but at the same time, maximize the quality (or resolution). My normal route has been to encode at 640x432, then stretch back to 16/9 resulting in a 787x432 video. I was going to try to improve this a bit from 432p to 480p. When you say suboptimal, what do you mean? I'm not sure how Apple handles it and still produce good videos from their store.