Improved H.264 Compression Holds Down File Sizes on 1080p iTunes Store Content

[rafaelcordoba]

guys, does anyone have a good explanation why sometimes in bluray or itunes hd content, some scenes with fast moving objects/characters usually have some "dirty pixels" around the moving object?

it seems that this is a problem in my TV or HDMI cable, because I don't get this "dirty" around fast moving objects on iMac 27" screen.

Does it make a difference LCD vs LED vs Plasma TV's on these matter?

 

[bsolar]

I don't think so. Why wouldn't they already use the better encoding strategy before? This technology hasn't changed recently.

Because even if the technology was there, you didn't have enough processing power on the Apple TV to make use of it. The new Apple TV is much more powerful, allowing a higher resolution and more refined encoding profiles.

 

[MagnusVonMagnum]

I think Apple needs to really make sure everything has at minimum Dolby Digital (unless the studio explicitly does NOT master in Dolby/Multichannel) and that they should add DTS-ES Discrete and Dolby Digital Plus in to the specs too. DTS-ES is totally underrated, you can pass all 7 discrete channels down optical ( and if your receiver doesn't support it then you just get the 6 channel core or the matrix 7 channel in 6), regardless its 24-bit and 768kbps and Dolby Digital Plus can go even lower with up to 7.1 discrete channels (netflix uses DD+), Netflix supposedly uses as low as 256kbps 7.1 Dolby Digital Plus which is pretty low but Dolby has always been about advanced compression (vs DTS which hasn't so I think Apple will avoid DTS).

Yeah, DTS-ES is awesome (i.e. what's the point in having a 6.1 home theater setup if nothing really uses it or does so poorly?), but sadly I don't even have very many DVDs that have it, but encoding it off a BD movie would work for me. Heck, I don't even have very many Dolby Digital EX discs when it comes to DVD (and some like half the Star Wars Prequels aren't properly encoded that do have it since my receiver doesn't turn it on automatically (the other half of them it does come on automatically). I watched Snakes On A Plane in DTS-ES, though and the difference was huge (Snakes literally sounded like they were coming up the back of my couch. It was pretty freaky. Without ES on, they were just non-descript around the room somewhere.)

Artificial turning on EX or ES modes helps if someone is sitting in the seats behind the main listening couch area (since the side surrounds are now in front of them and EX/ES here pulls the effects largely into the back of the room for them), but for the regular listening couch, non encoded EX or discrete ES material is nearly indistinguishable from turning the speaker off from the main listening couch.

Apple should at least support EX encoding (doesn't hurt to have it even if you're just using a 5.1 setup). The good news for people that use XBMC with AppleTV is that DTS-ES readily encodes into MKV files with no issues. I even have a DTS-ES music album by Sheryl Crow that works with regular WAV and/or Apple Lossless files (decoder picks it right up and properly decodes it).

 

[faroZ06]

Because even if the technology was there, you didn't have enough processing power on the Apple TV to make use of it. The new Apple TV is much more powerful, allowing a higher resolution and more refined encoding profiles.

It doesn't take much to play videos with better compression algorithms. Otherwise, watching a video on a PC would be really CPU-taxing. If an iMac G3 can play modern H.264, so can an Apple TV.

 

[AidenShaw]

It doesn't take much to play videos with better compression algorithms. Otherwise, watching a video on a PC would be really CPU-taxing. If an iMac G3 can play modern H.264, so can an Apple TV.

Actually, sometimes it does take a lot more to play the high profiles.

In particular, if you have hardware (GPU) decode for some profiles - then trying to play a "better" profile will depend solely on software (CPU) decoding.

In many cases (probably most cases on low-end (ATV) and mobile) the CPU simply can't handle decoding the video stream (it probably couldn't even handle the standard profiles without the hardware decode). It's not a matter of "profile x needs 10% more processing power", it's that "profile x-1" is handled by the hardware decoder and "profile x" has to be completely done in the CPU.

All H.264 is not equivalent - H.264 is a "family of standards".

Read up on H.264 before making such an ill-informed comment - start at http://en.wikipedia.org/wiki/H.264 .