Modulus change from 16 to 2 - question

[Greg Staten]

Noticed about a hundred builds ago the modulus was changed from 16 to 2. Just wondering why the change was made all the way down to 2. I've always understood (from my testing with H.264 decode implementations) that a modulus under 8 was risky for compatibility. Have you all found that this is no longer a decode issue? Certainly 2 makes it easier to deal with arbitrary crops, but I've always made sure the math worked out to 8 when adjusting size and crops.

Thanks!
-greg

[mduell]

It's less of an issue than ever. iDevices, mainstream Android, Roku/WDTV/etc all support mod 2.

I didn't think 8 helped compatibility, I thought it was 16 or no improvement.

[Deleted User 11865]

Some devices have issues when the dimensions don't divide cleanly by 4. Never encountered any, though IIRC TedJ did. In 99.9% of cases though, mod 2 will work fine.

[TedJ]

I'd seen playback issues with the PS3 with mod2 dimensions, although I haven't checked in about 2 years.

[Greg Staten]

Thanks for the information. Hadn't realized that Mod2 had been so widely adopted.

Thanks!
-greg

[jamieburchell]

I'm wondering how the videos I've previously encoded with Loose/Mod16 are inferior to Mod2? Is it that mod2 can get closer to the intended aspect ratio? Does it really matter/notice?

[GregiBoy]

No it really doesn't matter so long as they play on your target devices.

I would suggest that you would not be able to pick any difference.

Give it a go though on a chapter or so of your favourite movie and see if you can pick anything!