So I am about to return the new mac mini I just bought - it is just not strong enough to play high bitrate h.264 files and HDDVD/bluray rips, etc.

I am really torn as to what to turn to next - I was somewhat attracted to the idea of an OSX-based HTPC ... but I am not going to put some big Mac tower case in my living room, so that's that.

But then it hit me - why not a mac laptop ?

The new macbook beats the latest mini in both GHZ (2.2 vs. 2.0) and with the graphics chipset (gma 3100 vs. gma 950)

Any comments on this idea ? Any pitfalls I should know about ?

I am assuming, of course, that I can run an external display off of a macbook with the lid fully closes, and also assuming that the same 1366x768 DVI output I was getting from the mini can be got from the macbook...

But the big question is, what does having x3100 get me that GMA 950 did not ? The big problem with GMA 950 was that there was no hardware support in VLC for the gma 950 ... but is there for the x3100 ?

The known quantity is that my GHZ is +10% ... but I don't know if that will improve the (terrible) performance on very high bitrate 1080p h.264 files ... so will the x3100 chipset make a huge difference ? Does VLC have support for this hardware ?

All comments appreciated...

Intel's own marketing lit about the x3100 doesn't claim h.264 1080p support. There's 1080p support for VC-1 and MPEG 2. And that leaves out the software issue completely. The CoreAVC guys have been promising Quicktime and OS X support for some time, and the latest rumor is 2008 CES. But they have also been promising hardware support and have not delivered. I would get a cheap Mini refurb, save the money, and wait for this all to get resolved down the line.
The Santa Rosa will play more h.264 than the Mini, but you will probably still find some that don't work.

I don't understand why we aren't seeing all manner of pc-card and USB based hardware decoders ...

I know there are pcmcia hardware decoders for mpeg-2, but I don't see any pc-card or USB decoders for mpeg-4, or for h.264.

It seems like such a no-brainer - why in the world are we relying on our CPUs for this kind of thing when we could just offload it to a USB stick and forget about it?

I don't think USB 2.0 is up to the task of transporting uncompressed 1080p video in real time?

1920 x 1080 = 2,073,600 pixels
x 30 fps = 62,208,000 pixels /second
x 3 bytes per pixel = 186,624,000 bytes per second

according to Wikipedia, the optimum bandwidth of USB 2.0 is 60 MB/sec, so it seems to me that USB 2.0 is less than a third of the speed needed to do what you suggest under ideal conditions, and this is the reason for the lack of USB HD decompression sticks.

Hmmm... well the files I am playing, while very high bitrate in the world of HTPCs (30-40 megabits/s) are much, much lower in bitrate than USB 2.0.

Are you sure it is 3 bytes/pixel ? I think you are thinking of the calculations for an actual video signal, as in, VGA or DVI - video files are nowhere near this density. Even a ridiculously high bitrate movie clip would only be 80 megaBITS/second which would be one sixth the speed of USB 2.0.

So yes, you're right, USB 2.0 would not be up to the task of connecting a 1920x1080 flat panel at 24 bit color, but that's not what we are talking about here...

Since I doubt apple will ever put any horsepower in such a small package you might look into building an osx86 based PC in a small form factor.

Why not burn to disk one of the h.264 films you want to view, bring it to the Apple store with you and try it in the computers that interest you? That should give you a quick answer.

Hmmm... well the files I am playing, while very high bitrate in the world of HTPCs (30-40 megabits/s) are much, much lower in bitrate than USB 2.0.

Are you sure it is 3 bytes/pixel ? I think you are thinking of the calculations for an actual video signal, as in, VGA or DVI - video files are nowhere near this density. Even a ridiculously high bitrate movie clip would only be 80 megaBITS/second which would be one sixth the speed of USB 2.0.


24 bit might be overkill but even 16 bit would be too much for USB, even an incredibly ugly 8 bit picture would be too close for comfort, so the actual value is irrelevant.

The movie clips you are playing are compressed, once uncompressed any 1080p/30 stream should be the same massive amount of data. And if they are uncompressed by a USB device, they pretty much by definition have to be streamed back into your computer in all their bloated glory over the USB connection.

As an aside, the Wikipedia article on USB 3.0 indicates it will have the bandwidth to do this.

So I am about to return the new mac mini I just bought - it is just not strong enough to play high bitrate h.264 files and HDDVD/bluray rips, etc.

I am really torn as to what to turn to next - I was somewhat attracted to the idea of an OSX-based HTPC ... but I am not going to put some big Mac tower case in my living room, so that's that.

But then it hit me - why not a mac laptop ?

The new macbook beats the latest mini in both GHZ (2.2 vs. 2.0) and with the graphics chipset (gma 3100 vs. gma 950)

Any comments on this idea ? Any pitfalls I should know about ?

I am assuming, of course, that I can run an external display off of a macbook with the lid fully closes, and also assuming that the same 1366x768 DVI output I was getting from the mini can be got from the macbook...

But the big question is, what does having x3100 get me that GMA 950 did not ? The big problem with GMA 950 was that there was no hardware support in VLC for the gma 950 ... but is there for the x3100 ?

The known quantity is that my GHZ is +10% ... but I don't know if that will improve the (terrible) performance on very high bitrate 1080p h.264 files ... so will the x3100 chipset make a huge difference ? Does VLC have support for this hardware ?

All comments appreciated...


Something to be aware of. Macbooks & MacBook Pro's rely on the display being opened for proper ventilation. As soon as you close the display and use an external monitor, you block the air from going through the keyboard. which then has the effect of the fans operating at full speed and laptop heat increasing about 15-20 Degrees..

Just a heads up from my own experience

Robert, not according to Apple--can you link to the knowledge base or support document which supports your claim?

Is that degrees C or degrees F that you think you've noticed a 15-20 degree difference with closed lid???

I don't understand why we aren't seeing all manner of pc-card and USB based hardware decoders ...

I know there are pcmcia hardware decoders for mpeg-2, but I don't see any pc-card or USB decoders for mpeg-4, or for h.264.

Broadcom has one (PCIe mini card), but it's being sold in bulk to laptop vendors and not individually.

X3100 graphics add full HW decode for MPEG-2 and HW acceleration for VC-1, and some advanced deinterlacing over the GMA950, but nothing for high-profile H.264. You're gonna have to rely on your CPU power to do that. 2.2Ghz C2D may be enough, but it will be tight. Really depends on the efficiency of the software for that one.

Broadcom has one (PCIe mini card), but it's being sold in bulk to laptop vendors and not individually.

X3100 graphics add full HW decode for MPEG-2 and HW acceleration for VC-1, and some advanced deinterlacing over the GMA950, but nothing for high-profile H.264. You're gonna have to rely on your CPU power to do that. 2.2Ghz C2D may be enough, but it will be tight. Really depends on the efficiency of the software for that one.

Thank you - that's very interesting. I have seen that broadcom card, actually - also very interesting.

Since you seem to have a lot of knowledge on this subject, would you tell me: is there anything useful at all in the GMA 950 ?

What I mean by that is, if a player software such as VLC had full GMA 950 specs and did as much optimization as they could with what is available (albeit, not much) how much better off would h.264, mpeg, and VC-1 be, as compared with _NO_ optimization and doing everything with raw CPU ?

Is there anything that can be salvaged from a GMA 950 with software written directly for it ?

The reason I ask is, VLC has nothing in it related to the GMA 950, so when you run VLC on a mac mini, it is pure CPU for everything. If they were to put routines in to take advantage of whatever the GMA 950 has available (again, admittedly not much) what would they gain ?

(the mini seems to do fine with very high bitrate mpeg/.ts - it is h.264 and vc-1 that I am looking for optimization with ...)

thanks.

The GMA950 has HW motion compensation for MPEG-2, and adaptive deinterlacing support, but that's about it. It's capable of some nice graphical eye candy (Beryl in Linux, Aero Glass in V*st*) and can drive 1080p to a monitor without flinching (provided your CPU does the heavy lifting on the decode), but for video optimization that's about all the "special" features it has.

I would assume that Apple did as much optimization as they could on GMA950, so I suspect you're getting what you can out of it now on Apple software.

There's no hidden VC-1 or H.264 functionality in there. It's possible you could get some minor improvement to performance on MPEG-2 if VLC could access the MC functionality, and you might save on CPU cycles for any codec if you could use the HW deinterlacing, but that would only be on interlaced material (480i, 1080i) shown on a progressive monitor (which admittedly is a large amount of material).

I would assume that Apple did as much optimization as they could on GMA950, so I suspect you're getting what you can out of it now on Apple software.


Right, but I am using VLC which has no optimization or knowledge of GMA 950 at all ... for all videos I am using pure CPU for all functions.

And I _am_ getting frame drops and stuttering on high bitrate mpeg files, like this one:

ID_VIDEO_ID=0
ID_AUDIO_ID=0
ID_FILENAME=Fergie.Concert.for.Diana.MPEG2.1080i.40Mbps.422-aB.mpg
ID_DEMUXER=mpegps
ID_VIDEO_FORMAT=0x10000002
ID_VIDEO_BITRATE=39917200
ID_VIDEO_WIDTH=1920
ID_VIDEO_HEIGHT=1080
ID_VIDEO_FPS=29.970
ID_VIDEO_ASPECT=0.0000
ID_AUDIO_CODEC=mp3
ID_AUDIO_FORMAT=80
ID_AUDIO_BITRATE=256000
ID_AUDIO_RATE=48000
ID_AUDIO_NCH=2
ID_LENGTH=0.00
ID_VIDEO_CODEC=mpegpes

Do you think the motion compensation would provide a noticable difference on files like this, given that we are starting from _zero_ usage of the GMA 950 ?

Noticable? Sure. Whether it will be enough to help with 40Mbps MPEG-2 or not is questionable.

I'm pretty surprised it is balking, actually, as people have been playing ripped Blu-ray on GMA950 solutions for months (on non-optimized SW like VLC and MPC).

Noticable? Sure. Whether it will be enough to help with 40Mbps MPEG-2 or not is questionable.

I'm pretty surprised it is balking, actually, as people have been playing ripped Blu-ray on GMA950 solutions for months (on non-optimized SW like VLC and MPC).

Yes, but probably not on OSX Leopard ... I get the sense that is not the most bloat-free operating environment around...