Author Topic: bluray and hddvd playback  (Read 11272 times)

cobradevil

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Re: bluray and hddvd playback
« Reply #45 on: December 17, 2007, 08:42:02 am »
Well the hardware recommendations are insane.

If you do not have video acceleration then you need a heavy machine.

Video acceleration is only available for mpeg2 so with mpeg 4 the cpu needs to get it going. Also when you have a hd-dvd vc-1 or x264 then your cpu has to do al the decoding before sending it to the graphics card.

Intel is busy with a new interface called vaapi but nvidia does not anticipate in that for the moment. http://www.freedesktop.org/wiki/Software/vaapi

Nvidia does support good accelerated playback on windows interfacing with directx. So you wil have to wait until nvidia opens the api to linux.

I dont think you wanna have a dualcore machine sitting at your living room making awfull sounds. Try buying a bluray or hddvd player which you can control using lmce.

With kind regards,

William van de Velde

Matthew

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Re: bluray and hddvd playback
« Reply #46 on: December 17, 2007, 09:07:10 am »
Well the hardware recommendations are insane.

If you do not have video acceleration then you need a heavy machine.

Video acceleration is only available for mpeg2 so with mpeg 4 the cpu needs to get it going. Also when you have a hd-dvd vc-1 or x264 then your cpu has to do al the decoding before sending it to the graphics card.

Intel is busy with a new interface called vaapi but nvidia does not anticipate in that for the moment. http://www.freedesktop.org/wiki/Software/vaapi

Nvidia does support good accelerated playback on windows interfacing with directx. So you wil have to wait until nvidia opens the api to linux.

I dont think you wanna have a dualcore machine sitting at your living room making awfull sounds. Try buying a bluray or hddvd player which you can control using lmce.

I think that Blu-Ray and HD-DVD drives are available with HW decoders that can extract the discs' content to files under Ubuntu. Then there needs to be an equivalent of decss to unencrypt them. But the files resulting from that should be playable with relatively cheap HW (though HDMI 1080p output of any content isn't cheap, and maybe not available at all). This isn't much different from playing regular DVDs, which need the codecs in their players for HW acceleration that lets relatively cheap CPUs manage the playback.

cobradevil

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Re: bluray and hddvd playback
« Reply #47 on: December 17, 2007, 09:30:14 am »
Well try to play a full hd movie with your linux box without encryption and you will see that it won't playback that easily.

Sound lag video tearing. Mplayer saying your system is to slow.
(system p4 3 Ghz 1GB ram nvidia 7600GS)

With kind regards,

William van de Velde

blackoper

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Re: bluray and hddvd playback
« Reply #48 on: December 17, 2007, 02:14:29 pm »
Well try to play a full hd movie with your linux box without encryption and you will see that it won't playback that easily.

Sound lag video tearing. Mplayer saying your system is to slow.
(system p4 3 Ghz 1GB ram nvidia 7600GS)

With kind regards,

William van de Velde


that system is too slow. My primary display box is rolling with a 3.35 ghz intel e2180 dual core and 2gb of fast ram... even the original hd-a1 from toshiba had to have 2.4ghz processor to play correctly so with overhead there is no way that 3ghz processor will cut it without some kind of hardware decoder.

Matthew

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Re: bluray and hddvd playback
« Reply #49 on: December 17, 2007, 04:52:22 pm »
Well try to play a full hd movie with your linux box without encryption and you will see that it won't playback that easily.

Sound lag video tearing. Mplayer saying your system is to slow.
(system p4 3 Ghz 1GB ram nvidia 7600GS)

With kind regards,

William van de Velde


that system is too slow. My primary display box is rolling with a 3.35 ghz intel e2180 dual core and 2gb of fast ram... even the original hd-a1 from toshiba had to have 2.4ghz processor to play correctly so with overhead there is no way that 3ghz processor will cut it without some kind of hardware decoder.

According to some people working on drivers for MPlayer that use the PS3 Cell SPUs (DSPs), 1080p requires 3.1MBps output, which doesn't seem to require a 3GHz dual-core.  That would offer about 1000 instructions per byte (GHz/2 * 2cores), which seems overkill considering how much each pipelined CISC instruction does in this kind of application. A 2.4GHz single-core CPU would seem to be enough, if its RAM/VRAM buses are fast enough.

blackoper

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Re: bluray and hddvd playback
« Reply #50 on: December 18, 2007, 12:21:01 pm »
my athlon 64 3700+ has frame skips with full hddvd and bluray discs. Also when I don't overclock the e2180 it also has frame skips this is with the mplayer and ffmpeg svn from about 3 weeks ago.

Matthew

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Re: bluray and hddvd playback
« Reply #51 on: December 18, 2007, 02:15:40 pm »
According to some people working on drivers for MPlayer that use the PS3 Cell SPUs (DSPs), 1080p requires 3.1MBps output, which doesn't seem to require a 3GHz dual-core.  That would offer about 1000 instructions per byte (GHz/2 * 2cores), which seems overkill considering how much each pipelined CISC instruction does in this kind of application. A 2.4GHz single-core CPU would seem to be enough, if its RAM/VRAM buses are fast enough.

Actually, I read that bitrate wrong. It's (claimed to be) 3.1MB per frame, not per second. So 30 fps means 93MBps, 744Mbps. 3GHz/dual is about 32 instructions per byte. If pixels are 32bit, that's about 128 instructions per byte. Still seems like plenty, but perhaps 2.4GHz/single at 12 instructions per byte is too slow. And max HDMI bitrate of 10.2Gbps seems to clearly require a dedicated video ASIC, like on an nVidia display card.

chrisbirkinshaw

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Re: bluray and hddvd playback
« Reply #52 on: December 22, 2007, 04:55:41 pm »
You have to actually decode the MPEG stream... motion vectors, MBAFF, deinterlacing. etc

Matthew

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Re: bluray and hddvd playback
« Reply #53 on: December 22, 2007, 05:11:15 pm »
You have to actually decode the MPEG stream... motion vectors, MBAFF, deinterlacing. etc

Yes, but you don't actually run a decode loop on each byte, but rather on long run lengths in each frame. So while the brute force reduction to "12 instructions per byte is probably too slow" is possibly pessimistic, "128 instructions per byte is probably fast enough" is probably accurate. Because even operating on a few pixels at a time is probably time for more than about a thousand instructions to execute, which should be plenty, and I expect the actual amount is higher. But mere hundreds of instructions per processing iteration is probably too slow.

This kind of processing is exactly what video HW is for. Especially modern PC display chips, which are not only fast and have instructions tuned to the MPEG apps, but also have lots of parallelism. I wonder whether there's a way for a Core to harness a bank of nVidia chips to decode video into frames which aren't displayed locally, but streamed out to a relatively slow MD for display. Gonna need a fat fat LAN though.

chrisbirkinshaw

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Re: bluray and hddvd playback
« Reply #54 on: December 22, 2007, 06:18:28 pm »
Hmm. Isn't that going to be like watching a movie over VNC? ;-)

desmarch

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Re: bluray and hddvd playback
« Reply #55 on: December 22, 2007, 09:13:53 pm »
You have to actually decode the MPEG stream... motion vectors, MBAFF, deinterlacing. etc

This kind of processing is exactly what video HW is for. Especially modern PC display chips, which are not only fast and have instructions tuned to the MPEG apps, but also have lots of parallelism. I wonder whether there's a way for a Core to harness a bank of nVidia chips to decode video into frames which aren't displayed locally, but streamed out to a relatively slow MD for display. Gonna need a fat fat LAN though.

 ???
If I may: as I am not a IT geek (but rather a professional user), I am not sure to understand: When files are stored on the core and displayed on a MD, where and how are they decoded? By the core's CPU? By the MD's CPU? or by the MD's GPU? In other words, where is processing power needed?

Sorry if my question looks stupid but I would be happy to understand. :P

Thanks

tschak909

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Re: bluray and hddvd playback
« Reply #56 on: December 22, 2007, 11:25:08 pm »
by the MD's CPU. The core merely serves the files.

-Thom

Matthew

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Re: bluray and hddvd playback
« Reply #57 on: December 23, 2007, 12:06:58 am »
by the MD's CPU. The core merely serves the files.

A gigabit LAN could probably let the Core serve cheap MDs with decoded streams, maybe encoded with something really lightweight like HuffYUV (~60% as big). ffmpeg and MPlayer support HuffYUV, even a 2:1 YV12 version. The Core would have to be faster to accommodate. There's got to be a way to harness multiple videocards on the core without just using VNC, because that has no sound and has extra overhead for all the other VNC features - and the VNC client isn't really that lightweight.

desmarch

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Re: bluray and hddvd playback
« Reply #58 on: December 23, 2007, 03:45:35 am »
by the MD's CPU. The core merely serves the files.

-Thom

Thanks so much Thom for this very useful info. That was my guess. So an older Mobo with a simple Pentium IV or Athlon XP with enough memory and quick drives should do the trick.
Am I right if I say that it will be the same for tuner cards installed on the Core?

tschak909

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Re: bluray and hddvd playback
« Reply #59 on: December 23, 2007, 04:25:07 pm »
the same restrictions for mythtv apply for linuxmce in this respect.

-Thom