i200
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Re: x264

Mon Mar 05, 2012 1:57 pm

Hi all, i just came across this document that deals with x264 video:

http://scenerules.irc.gs/t.htm.....Vx264r.nfo

Basically it sets a video/audio quiality specs. Im wondering if Raspberry Pi is able to handle this files correctly.

If you dont want to read the document here is the brief:

Video codec: x264 (8-bit depth)
Container: MP4
Audio formats: VBR AAC LC (Low Complexity) [average 96-160 kbps].

Thanks for any info.


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zag
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Re: x264

Mon Mar 05, 2012 2:18 pm

I'd be interested to know this too.

I Hope so as it will make the xbmc implementations usable as a media centre then.
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jamesh
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Re: x264

Mon Mar 05, 2012 2:39 pm

The device can handle H264 high profile at 1080p30. Search for XBMC - this has been covered extensively on the forum and site.
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i200
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Re: x264

Tue Mar 06, 2012 2:19 pm

JamesH, thats exactly what i was looking for (XBMC). After a bit of research it seems thats the perfect option even though the minimun hardware is supposed to be 1Ghz CPU and 256Mb RAM to handle H264 files (im NOT expert, this comes for Google search).

Thanks for all the help given

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Re: x264

Tue Mar 06, 2012 2:52 pm

i200 said:


JamesH, thats exactly what i was looking for (XBMC). After a bit of research it seems thats the perfect option even though the minimun hardware is supposed to be 1Ghz CPU and 256Mb RAM to handle H264 files (im NOT expert, this comes for Google search).

Thanks for all the help given


H264 is decoded by the GPU, so CPU speed is irrelevent.
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shivansps
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Re: x264

Wed Mar 07, 2012 6:41 am

The CPU always do something, its never 100% on the gpu. How much the cpu do depends on how good the gpu decoder is, also the bitrate is VERY important.

This is a test with a A10 cpu, someone need to try something similar to this with Raspi BCM.


i200
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Re: x264

Wed Mar 07, 2012 8:56 am

Thanks.

Ill get a Raspberry Pi anyways, have lots of ideas for this device ... One of them is a cheap and small internet radio alarm clock.

Again, thanks for all the help.

PS- if for some reason the device doesnt handle this kind of files ill post it here.

ethelthefrog
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Re: x264

Mon Apr 02, 2012 10:17 am

shivansps said:


The CPU always do something, its never 100% on the gpu. How much the cpu do depends on how good the gpu decoder is, also the bitrate is VERY important.



Given that the 2835 can decode H264 with the ARM switched off, the only thing the ARM is going to be doing to play back these streams is to shift the raw data into the GPU portion of the chip.

Paul.

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Re: x264

Mon Apr 02, 2012 10:24 am

All the Arm does is decode the audio stream. Everything else is done by the GPU. There is some CPU overhead, but not much. The Arm could certainly be underclocked during playback.
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Re: x264

Mon Apr 02, 2012 12:35 pm

Not really for HD playback.

6-channel audio decode takes ~50% of ARM's CPU.

Reading the file (e.g. over network) plus demuxing the stream, buffering the data and passing to GPU takes ~50% of ARM's CPU.

You've got a much better chance of underclocking the GPU than the ARM during HD video playback.

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Re: x264

Mon Apr 02, 2012 1:18 pm

I defer to Dom's more informed knowledge! hadn't realised the audio decode took so much oomf. Thanks Dom.
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Re: x264

Mon Apr 02, 2012 1:41 pm

what he said...

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Re: x264

Mon Apr 02, 2012 1:47 pm

JamesH said:


I defer to Dom"s more informed knowledge! hadn't realised the audio decode took so much oomf. Thanks Dom.


Or indeed that the background tasks for getting streams in to the GPU were so demanding.
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