edzieba
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Re: h.264 decoding level

Fri Jul 29, 2011 7:25 pm

The spec sheet mentions h.264 high profile decoding, but does not mention level. Level 4.1 would cover most video commonly available (720p60, 1080p24 and 1080i60), including Blu-ray content. Level 4.2 would extend this to 1080p60, rarely found natively (usually only encountered when playing back raw full-screen captures), but useful when deinterlacing 1080i. Level 5.1 would allow playback of 3D content, but the requirements of essentially playing back two level 4.1 streams concurrently are probably too onerous for an embedded platform of reasonable cost.

Level 4.1 or 4.2 would definitely be the sweet-spot for playback of all but specialised video, and would almost instantly make the RaspberryPi the media streamer of choice (for those willing to solder on an IR receiver, that is). A cursory google only turned up ARM11 SoCs with Level 3.1 support at high profile though, so even level 4 support (1080 playback, but not directly from Blu-ray) might be pushing things.

eben
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Re: h.264 decoding level

Fri Jul 29, 2011 7:47 pm

We support Level 4.1 playback. We actually support encoding at this level as well on the SoC, but with no (publicly-documented) camera interface in the earliest version we're not advertising this widely.

Svartalf
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Re: h.264 decoding level

Fri Jul 29, 2011 7:52 pm

Heh... eben beat me to it. Think Roku2 XS, edzeiba... That should give you an idea what these are capable of doing, video-playback wise. Now, does no publicly documented camera interface mean the encode engine aspect, or a pluggable camera?

edzieba
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Re: h.264 decoding level

Fri Jul 29, 2011 10:06 pm

Wow, colour me impressed, that little ARM has some serious grunt!
Speaking of encoding, coupled with multiple native USB2 ports and a couple of PS3 eye cameras, it would make for an excellent video capture rig head. Real time capture and encoding (the PS3 eye transmits video uncompressed) for either streaming over ethernet to a central server, recording to a USB HDD (dirt cheap security camera system with motion sensing and remote notification?), or recording and on-board processing. Stereo cameras for a super-cheap SLAM rig on a robot maybe?

jamesh
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Re: h.264 decoding level

Sat Jul 30, 2011 8:00 pm

It's not the ARM, it's the GPU that does all the hard work.
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eben
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Re: h.264 decoding level

Sun Jul 31, 2011 11:10 am

On the camera interface point, things are a little complicated. The GPU is responsible for the camera interface. Commercial products based on this chip specify a camera module, and there is then a substantial effort involved in writing a GPU-side camera driver which controls lens and sensor configuration, and a tuning configuration, which specifies how the on-chip image sensor pipeline deals with incoming data. This is a multi-month effort, which must be repeated for every camera module, and uses closed-source tools which we're not able to release.

We may in due course do one of two things:


Find a camera module and do the development work ourselves. This is complicated by the rapid pace at which manufacturers EoL their modules.
Find a way to allow the open source community to do a driver and rough tune for a camera on the ARM side. This is complicated by manufacturers reluctance to release detailed camera specs to the community.


So in summary, it's complicated, but we're thinking about it.

marked
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Re: h.264 decoding level

Sun Jul 31, 2011 1:07 pm

can't you get some of this driver and camera info from android development sources, or is it too tuned for the OS?

Michael
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Re: h.264 decoding level

Sun Jul 31, 2011 2:17 pm

Do the leopardboard guys have appropriate cameras you could use?
http://designsomething.org/leo.....ories.aspx

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liz
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Re: h.264 decoding level

Sun Jul 31, 2011 8:51 pm

Oo - leopardboard is new to me. We'll have a squizz.
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Svartalf
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Re: h.264 decoding level

Mon Aug 01, 2011 5:00 pm


Find a way to allow the open source community to do a driver and rough tune for a camera on the ARM side. This is complicated by manufacturers reluctance to release detailed camera specs to the community.


Heh... Depends on the module you're using. Most USB webcams these days are UVC units- and Linux has that. For this sort of thing, if there was a way to get the video stream into the compression pipeline and back out to the device as compressed into the proper transport, it'd probably work out.

eben
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Re: h.264 decoding level

Mon Aug 01, 2011 10:02 pm

Good tip. If we can't figure out a way to use cellphone modules, we'll probably end up doing exactly that.

Svartalf
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Re: h.264 decoding level

Tue Aug 02, 2011 2:57 pm

Quote from eben on August 1, 2011, 23:02
Good tip. If we can't figure out a way to use cellphone modules, we'll probably end up doing exactly that.

You're welcome, eben. I'd like to see this actually take off in some amazing directions. If you need another volunteer, I'm up for it (though I'll have slightly variable availability from time to time...) and I've done all sorts of Embedded Linux stuff (which, technically, this is...) for easily 14+ years now.

eben
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Re: h.264 decoding level

Thu Aug 04, 2011 9:17 pm

Thanks. We're going to need all the third-party help we can get building out the software offering after launch.

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