MPEG-4 AVC/H.264 decoder help

andy

Hi im a bit new to these decoders.

I have a couple of questions regarding decoder for  MPEG-4 AVC/H.264. In regards to hdtv playback.

I have windows xp sp 2 with windows media player 10 with all updates to date, nvidia 7800 gtx graphic card with latest nvidia forceware graphic driver and latest purevideo installed. Its hooked up to my lg 42quot; monitor (M4200C, 1360x768 panel).

I have tried to play of  some hdtv 720p: MPEG-4 AVC/H.264 and it seems to work fine. But dunno what decoder im using. I guess its purevideo? In that case is this a good decoder (should have hardware support atleast for microsofts wmw-hd dunno about AVC)?

I have ffdshow installed. But only choosed divx and xvid, ac3 and dts in that package. So didnt install the rest.

I want to have the best quality. Cpu resources comes in second place. Which decoder should i use?

I also have terratek 2.2, windvd 7, and powerdvd 6 at hand if needed.

And whats the diffrence of wmw-hd 720p and avc 720p?

I see microsoft says its 720p (progressive) then its like only 25-30 fps (frames pr second). I thought progressive was 50-60 fps. So to me it looks like microsofts so called 720p is more like 720i (interlaced)?

Maybe AVC is real progressive with 50-60 fps?

Pls help a noob ^^

First, whatever decoder you are using the qialty will be the same beacuse h.264 decoding is bit exact. I kinda doubt you are using purevideo from nvidia, I thought this is not yet available (needs some yet unreleased drivers). To see what you are using, use Media Player classic, right click on the playing video, there is a category called Filters, you'll see there what filters you are using. The fastest h.264 decoder is CoreAVC, but my guess is that you are using the one from Nero. If it work fine (no hiccups or anything) you have nothing to worry about, you won't get extra quality with another decoder.

And about 30p, 60i etc, you have no need for 60p in movies, only sports and maybe documentaries. Movies are shot in 24 fps so 60p only clones frames and loads your cpu for nothing. The way they are  broadcast is this: 60p for 720p, and 60i for 1080i, because of bandwidth, you need a lot af that to put 60p on 1080.


Originally Posted by DaodanFirst, whatever decoder you are using the qialty will be the same beacuse h.264 decoding is bit exact. I kinda doubt you are using purevideo from nvidia, I thought this is not yet available (needs some yet unreleased drivers). To see what you are using, use Media Player classic, right click on the playing video, there is a category called Filters, you'll see there what filters you are using. The fastest h.264 decoder is CoreAVC, but my guess is that you are using the one from Nero. If it work fine (no hiccups or anything) you have nothing to worry about, you won't get extra quality with another decoder.

And about 30p, 60i etc, you have no need for 60p in movies, only sports and maybe documentaries. Movies are shot in 24 fps so 60p only clones frames and loads your cpu for nothing. The way they are  broadcast is this: 60p for 720p, and 60i for 1080i, because of bandwidth, you need a lot af that to put 60p on 1080.

In the newest foreceware drivers and purevideo like 1-2 weeks old, h264 should work fine. And i dont have much from nero installed. So i guess im using purevideo.

But as long as it says progressive 720p dosent that require 50-60 frames pr second? If its 25-30 i should say 720i? Am i right or wrong here? I get ur point about whats needed ofc. So then it would be preferable to get 1080i instead of 720p?

But whats the real diffrence if u compare hdtv mpeg4 wmw-hd and mpeg4 avc?

Thanks for your answers.

I have a 6600GT and it should suport H.264 hardware decoding, I'll see what drivers I can find, maybe you're right. If it's 720p than it's 720p. You can't get 720i in h.264 anyway. And what do you mean by quot;require 60 fpsquot;? You can play 15 fps movies as well. Or do you mean the standard? The standard, as said it's the broadcasting one for the reaosns mentioned. You should get 1080i if you have a high resolution screen, otherwise you won't miss much.
And as for wmv vs AVC there are some differences. First it seems that wmv look more noisy (even if the noise wasn;t in the source). AVC looks more soft somewhat, but much less blocky etc. For high bitrate they are almost the same anyway. Depends on what you prefer after all. wmv is quite old now, MY opinion is that AVC is better.


Originally Posted by DaodanI have a 6600GT and it should suport H.264 hardware decoding, I'll see what drivers I can find, maybe you're right. If it's 720p than it's 720p. You can't get 720i in h.264 anyway. And what do you mean by quot;require 60 fpsquot;? You can play 15 fps movies as well. Or do you mean the standard? The standard, as said it's the broadcasting one for the reaosns mentioned. You should get 1080i if you have a high resolution screen, otherwise you won't miss much.
And as for wmv vs AVC there are some differences. First it seems that wmv look more noisy (even if the noise wasn;t in the source). AVC looks more soft somewhat, but much less blocky etc. For high bitrate they are almost the same anyway. Depends on what you prefer after all. wmv is quite old now, MY opinion is that AVC is better.

To my knowledge the human eye require 50 fps to see it as movie. But then they made interlaced due to bandwith issues.  And what it does is that it deliver half the frames. and each time only shows half of the picture, line 1 3 5 and so on and on the next picture shows 2 4 6 and so on. Therefore making double the frames by tricking the brain.

What 1080i realy is is 960x540 resolution? its a 1920x1080 picture where half the lines is showed each time.

Imo progressive must be superior to interlaced. Delivering higher resolution. Even 720p who delivers 1280x720 must be better than 1080i who gives 960x540 resolution?

Now i have heard that 1080i is better on slow moving stuff, and that 720p is better on action movies and stuff. But still the interlaced picture works by tricking the brain.

Deinterlacing makes interlaced back to progressive. Not entierly sure how it does that. But i belive it does it with filling in with fake pixels.

I might be off. But reason im saying this is that i was under the impression that 720p generaly is superior to 1080i. Ofc 1080p beats all.

My panel is 1360x768. And its capable of showing 720p and 1080i. Now if 1080i gave a 1920x1080 picture it couldnt show the entire picture. But it does i belive since 1080i is only 960x540. And therefore 720p with 1280x720 resolution must be better since it uses more of the pixels each time.

But then again if hdtv movies are shot at 24 fps then 1080i must be superior since any other frames is fake anyway?

Only vertical res will be half (so 1920x544). And as for 720p being better, it's hard to believe, especially if that 720p comes from an 1080i (usually the case). The best way is to compare yourself.
And if the movie was shot in 24 fps, I find it hard to believe that adding clones will make the motion smoother.


Originally Posted by DaodanOnly vertical res will be half (so 1920x544). And as for 720p being better, it's hard to believe, especially if that 720p comes from an 1080i (usually the case). The vest way is to compare yourself.
And if the movie was shot in 24 fps, I find it hard to believe that adding clones will make the motion smoother.

You are correct. Ofc only vertical frames. Thanks for correcting me

But then again on my display the 1080i will be 1360x544. Since its not a 1920x1080 panel (its a 1360x768 panel). I guess. So then its like 1360x540 vs 1280x720 i guess. Cant be much of a diffrence in reality. But then again if the movie is shoot in 1080i as you say i get your point.

It has a hdtv component input that says 1080i/720p. But im atm using the dvi plug (the plug is hdcp compliant but there is no graphic card for sale yet with dvi-hdcp, but then again luckily no media using hdcp yet).

Ah i was reading some about it i get it a bit more now. Movies are originaly filmed in 24 fps progressive.

Then the eye only needs those 24 fps to see it as a moving image. But due to bandwith issues they used to make it into 2 smaller frames instead. Interlaced.

But computers and monitors show progressive (as well as more expensive dvd players and hdtv players and new edtv/hdtvs).

So it takes the interlaced frames and constructs its back to progressive by a method called de-interlacing.

So the video is shoot in progressive. And some times distributed as interlaced. And then we de-interlace it back to progressive on the other side.

But heck progressive must be superior then.

You're getting there, but you still don't quite get interlacing right. It doesn't automatically mean half the vertical resolution when compared with progressive content at the same resolution. For slow motion, interlaced content has almost the same resolution as progressive. For high motion the vertical resolution will be halved, but at the same time the field rate is 50 or 60 Hz. So interlacing is kind of a motion compression trick. Also most of the video (not film) material is still shot interlaced. This will change only with HDTV, as 720p25/60 gets more popular. Still, 1080i is probably used for a lot of content too until 1080p is reasonable.

Now, when movies are broadcast in 1080i25, they actually correspond to directly with 1080p24 in resolution because only the framerate is speeded up a bit and no interlacing is needed. However, in 1080i30 (NTSC/ATSC), movies are broadcast as telecined video. This is a technique to playback 24fps content on a 30i display with the least possible damage to the video and playback smoothness. The telecine process can be inversed (ivtc) to produce the original 1080p24 video with full resolution too.

Also H.264 does support interlacing, so 720i30 is quite possible (although a bit non-standard). It's only that x264 doesn't yet support interlaced encoding and many decoders don't support decoding it.

Make sure you check out the following on interlacing:

wiki/Interlaced

Like my lg 42quot; f example. It has a 1366x768 panel its says.

Recommended resolution using dvi is 1360x768 60Hz. Im using that.

It also has a component port who says 720p/1080i. Havent tried that one.

But what i dont get is. How can 1080i be any better on my monitor than f example 720p? Since my monitor dont have 1920x1080 panel. It will then display 1360x540 when im watching 1080i right? 720p would then give me 1280x720 right? Not much of a diffrence?

Maybe i should watch 1080p movies instead then and get 1360x768 from that?

Not sure here.... Is there some kinda trick since 720p and 1080i almost contains the same amount of data pr frame?

But still i cant see how 1080i can be better on a lcd panel that runs in 1360x768 60Hz. Since it wont use the horizontal resolution of 1920 anyway. This monitor cant display more than 1360 horizontal.

So i guess then that 720p or 1080p would be the best for it. 1080i looks good to anyway. But my computer will deinterlace the 1080i stream anyway (since computers/lcd monitors show video in progressive mode).

Whats is the best to input a 720p (1280x720) into a panel that gives 1360x768, or to input 1080p (1920x1080) into a 1360x768 panel?

720p has to few pixels and will probably make some fake pixels. 1080p has to many pixels and some will probably be removed. Which would be the best then on my panel? 720p or 1080p?

Im guessing 1080p since there will be noe fake pixels? Am i right?


Originally Posted by magnusrBut still i cant see how 1080i can be better on a lcd panel that runs in 1360x768 60Hz. Since it wont use the horizontal resolution of 1920 anyway. This monitor cant display more than 1360 horizontal.

Resizing 1080i/p (when we're talking about film material, not interlaced video) to 1360x768 or 1280x720 can be better than 720p because there are a lot more details in the video to start with.

So i guess then that 720p or 1080p would be the best for it. 1080i looks good to anyway. But my computer will deinterlace the 1080i stream anyway (since computers/lcd monitors show video in progressive mode).

As I already explained, if the 1080i stream is a movie, deinterlacing with weave for PAL (same as not doing anything to the video) or performing IVTC for NTSC, produces the original progressive video that is as good as 1080p24. So 1080i50/60 is a lot better than 720p50/60 (the framerate is a waste anyway) for film material.

Whats is the best to input a 720p (1280x720) into a panel that gives 1360x768, or to input 1080p (1920x1080) into a 1360x768 panel?

Use VGA or DVI, make sure you have 1:1 pixel perfect video mode set, let the graphics card resize the video and be happy. If the graphics card can't downscale properly, use software resizing (bicubic is fine). For 1080i NTSC video you'll need a 3-2 pulldown filter in your player.

Im guessing 1080p since there will be noe fake pixels? Am i right?

This was answered above in this post. For film material 1080i/p is better. For other stuff like sports, 720p is the way to go since it doesn't require deinterlacing.