What is the difference between AVC and VC-1?

[mainman]

I know AVC was developed by Sony, and VC-1 was developed by Microsoft.

What is the difference between the two, which is more efficient right now? I heard something about 14mbit/s, which one has this, or do theyy both have it?

And which codec does the majority of HD-DVD titles use right now?

Thanks.

[marzetta7]

H.264 was NOT created by Sony but by the Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG). VC-1 I believe was co-developed by Microsoft.

You can learn more about both here...

http://en.wikipedia.org/wiki/H.264

http://en.wikipedia.org/wiki/VC-1

What codec is better, I think that is still up to debate.

[mainman]

Originally Posted by marzetta7

H.264 was NOT created by Sony but by the Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG). VC-1 I believe was co-developed by Microsoft.

You can learn more about both here...

http://en.wikipedia.org/wiki/H.264

http://en.wikipedia.org/wiki/VC-1

What codec is better, I think that is still up to debate.

http://en.wikipedia.org/wiki/VC-1

Although widely considered to be Microsoft's product, there are actually 15 other companies in the VC-1 patent pool

Is Sony one of those 15 companies? Because I remember reading somewhere that Sony developed a codec (something) together with Microsoft.

[hmurchison]

Both are similiar in that they use modern compression techiques to improve quality at lower bitrate.

VC-1 is a bit easier to encode/decode than AVC.

Trying to discern any real substantive difference will require digging deep down into the nuts and bolts of the codecs.

[Shadowself]

Originally Posted by hmurchison

VC-1 is a bit easier to encode/decode than AVC.

I don't understand this statement.

Are you saying AVC is more compute intensive (requires more compute cycles) than VC-1?

Otherwise, once the codecs are written into software (in the case of software used to compress video media) or firmware (in the case of players decompressing the video for playback) it does not seem to me that one is easier than the other. The software/firmware does all the heavy lifting for you.

Additionally some computer companies have provided video chat capabilities using AVC on their systems for a few years (at least two generations of CPUs back) with no special hardware or firmware required so it does not seem to me that AVC can be very compute intensive.

[hmurchison]

Yes AVC is definitely tougher to encode (roughly 8x/4x the power needed for encode/decode versus MPEG2) there is no free lunch if AVC is used on a disc the processors involved will have to have enough power to handle the extra crunch.

Here's a great explanation of why

http://www.tvtechnology.com/features/news/n_AVC.shtml

"AVC is more complex and may ultimately offer the potential for higher quality and more efficient coding. VC-1 is less complex and therefore, presumably easier to implement efficiently," Goldman said.

Examples of specific differences between AVC and VC-1 include AVC's use of six-tap filters versus VC-1's use of four-tap filters. AVC uses an entropy scheme known as CABAC (context-adaptive binary arithmetic coding) that is computationally intensive and therefore expensive to implement. VC-1, by contrast, uses high-order entropy coding that is less complex and less expensive to implement.

http://broadcastengineering.com/mag/...avc/index.html

Practical AVC encoding and decoding solutions must overcome substantial technical challenges. SD AVC compression requires around 10 times more processing power than MPEG-2, and there is now a dearth of ready-made silicon solutions for professional AVC compression applications. HD encoding compounds the challenge.

VC-1 seems to be the easier codec to master discs to from what I've seen but I think that in the next 5 years we'll see AVC pull forward in the quality department. I expect Sony to be more of a AVC proponent. Hell they may be in the patent pool for AVC.

[AV_Integrated]

Originally Posted by Shadowself

The software/firmware does all the heavy lifting for you.

Computationally, for the highest quality video, the hardware requirements and the software requirements are huge. Software is pretty standard, but once a codec is developed, tweaking the nuances of it to generate the highest quality video possible for any given situation is phenomenally complex.

This complexity lends itself to typically being far less than real time for encoding unless you have an incredible amount of horsepower driving the hardware. While you may see cheaper encoders that can do half frame @ 15fps with so-so quality that work on many PCs, finding an encoder that can do full HD, at full HD quality, in real time requires over 4x that processing power at the very least - typically a great deal more.

Likewise the decode is heavily hardware intensive. If you go to Apple's website and look at their HD movie trailers, you will see if your PC is up to the challenge of their 1080p trailers. Many PCs aren't going to make the cut, while some will. I know that neither of my computers can do 1080p cleanly. So, while it is in the software to perform the decode, and the decode does happen, it doesn't happen in real time at 30 frames per second or more as demanded by 1080p video.

As I said - it is incredibly processor intensive.

[Psiweaver]

yeah you better have some ram to get it done.

[gamerzus]

Exactly,For VC-1/CodecWMVHD9
Yourt looking at 256MB Video Ram Geforce 5800+-And onboard Ram,Try 768MB or more! Plus 2GHZ+ CPU -DVD files Running from Hardrive-.
VC-1 Is the only true! Proven HD video Standard Out there!
WMVHD is Breathtaking!
On an 30 Inch LCD running off of Windows Media Player Edition with The above mentioned specs,The qulaity is so solid and the Imax Imagry is stunning.I have all! the DVD's.
Blu-ray Mpeg-2 is just a stop gag,until they decide to go ahead and kill the DVD cash COW..That is why Blu-ray and HD-dvd still look pittyfull when compared to VC-1/WMVHD..or to Plain Mpeg-2 DVD for that matter.. They are stalling on releasing the good stuff...Just wait till Mpeg-2 DVD is dead.

[gamerzus]

Oh I did forget to mention that Sony And Microsoft are Competitors....PS3 VS Xbox 360.!
So It would be in the best intrest of Sony for the moment not pay into Microsoft's VC-1 Technology..That leaves us kind of out in the cold for a while.Lets see If AVC is a conteneder to VC-1 and if it's better to not to payinto the competetors pockets....LOL only time will tell.

[AV_Integrated]

Originally Posted by gamerzus

Exactly,For VC-1/CodecWMVHD9
Yourt looking at 256MB Video Ram Geforce 5800+-And onboard Ram,Try 768MB or more! Plus 2GHZ+ CPU -DVD files Running from Hardrive-.
VC-1 Is the only true! Proven HD video Standard Out there!
WMVHD is Breathtaking!
On an 30 Inch LCD running off of Windows Media Player Edition with The above mentioned specs,The qulaity is so solid and the Imax Imagry is stunning.I have all! the DVD's.
Blu-ray Mpeg-2 is just a stop gag,until they decide to go ahead and kill the DVD cash COW..That is why Blu-ray and HD-dvd still look pittyfull when compared to VC-1/WMVHD..or to Plain Mpeg-2 DVD for that matter.. They are stalling on releasing the good stuff...Just wait till Mpeg-2 DVD is dead.

You ever read posts that make you go... HUH???

Video encoding is as much art as it is science. Properly encoding in VC-1 OR AVC or MPEG2 requires a certain amount of bandwidth and a good encoder. Do a Google search and read about the quality of some MP3 encoders (audio) and you will find out quickly how poor encoding can seriously affect final quality.

So, leave DVD out of the discussion. MPEG2 & DVD do not mean the same thing. Likewise, HD-DVD already uses VC-1, so saying "...HD-dvd still look pittyfull..." when it is using VC-1 is questionable.

MPEG2 is fully capable of displaying pristing master quality HD content, but you need the space (50GB) and a high quality player (not Samsung) to deliver that content at its best. You also must have a near perfectly mastered movie to store it.

VC-1 and AVC can both deliver similar performance, in less space than MPEG2 can, but I have heard nothing that indicates that they can definitely provide greater quality. Greater quality in less space, yes. But, when MPEG2 is given room to flex its muscles, AVC and VC-1 don't beat it out. They both end up looking the same.

I believe Sony may go to AVC... maybe VC-1. Other studios will almost definitely go to VC-1. I believe all formats will have to as even in HD-DVD land the discs are nearing full capacity for movies and SD extra features. In upcoming years the switch will be on for HD features, and HD audio, and more interactivity - all of which won't be possible on 30GB at all, and definitely not with MPEG2 in use.