TOPIC: Raspberry Pi: FAQ

Raspberry Pi: FAQ 2 years 4 days ago #1

  • lrusak
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RASPBERRY PI FAQ


I would like to start this FAQ as we have been getting a large amount of the same questions regarding the Raspberry Pi.

Please post if you have something you would like added.

This is not to be used for disscussion of issues/problems.



MOVED: wiki.openelec.tv/index.php?title=Raspberry_Pi_FAQ


This will be expanded as more questions come up.
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Last Edit: 1 year 7 months ago by lrusak.
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Re: Raspberry Pi: FAQ 2 years 4 days ago #2

  • gunja99
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Good one. Thought we need it. Want to add something about havIng a good power cable? Also fixing the display to match video frame rate ?will add more if think about any.
Last Edit: 2 years 4 days ago by lrusak. Reason: stupid tapatalk
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Re: Raspberry Pi: FAQ 2 years 4 days ago #3

  • xe
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Superb work. Can I humbly suggest that the wording should be in the wiki and linked to here :)
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Re: Raspberry Pi: FAQ 2 years 3 days ago #4

  • Josh.43
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Great work; thank you. :)

I think this (FAQ) would be a fantastic place to have the "standard" RPI tweaks listed since it's already a great source and it ties in.

Of course with the disclaimer that the power supply must be confirmed as being powerful enough before "safely" or "unsafely" overclocking.

The config.txt tables on the link have not been updated, unfortunately, but there has been some work done by people in the forum to sort out the details. (I only overclock the CPU, since the GPU handles video files no problem, but with the single tweak of going up to 900Mhz, I know it's not optimal)

Also suggested for speeding up the default skin:
-Disable "Recently Watched" (Settings > Skin > Home Window Options > disable "Show Recently Added Videos")
-Disable Fanart (Settings > Skin > Background Options > enable "Hide Background Fanart")
-Disable reading thumbnails from the files (Settings > Video > disable "Extract thumbnail and video information")
-Note: recent builds of OpenELEC enable some more obscure optimizations, like DDS thumbnails of a small size

And one of the bigger white whales to speed up the interface: switch away from SMB (Can take up to 20% of the CPU in some cases)

Also, the DTS Audio issues are not just limited to NFS, as some of the higher bitrate 5.1+ DTS streams actually max out the CPU when it has to transcode them.
With the right TV, the Raspberry Pi can pass along the DTS stream untouched, meaning no more stuttering due to transcoding.
RasPi, Lego case, OpenELEC, arm_freq=850
raspberrypihtpc.wordpress.com
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Re: Raspberry Pi: FAQ 2 years 3 days ago #5

  • ozong
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Josh.43 wrote:
With the right TV, the Raspberry Pi can pass along the DTS stream untouched, meaning no more stuttering due to transcoding.

How is this done, could you explain please?

/oz

Synology Disk Station DS1511+ | ACER REVO 3700 & Raspberry Pi
OpenELEC Stable - Generic x86_64 4.0.4
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Re: Raspberry Pi: FAQ 2 years 3 days ago #6

  • gunja99
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If u want tested config overclocks:


arm_freq=850
gpu_freq=325
sdram_freq=425

(How on earth u get ur sdram to 600 lsuruk?! U must have an uber pi!) U done that without overvolting?
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Re: Raspberry Pi: FAQ 2 years 3 days ago #7

  • Josh.43
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ozong wrote:
Josh.43 wrote:
With the right TV, the Raspberry Pi can pass along the DTS stream untouched, meaning no more stuttering due to transcoding.

How is this done, could you explain please?

/oz

You must use HDMI, and enable passthrough (Settings > System > Audio Output)
(And, of course, your TV must support either decoding or passing through the raw audio stream)
RasPi, Lego case, OpenELEC, arm_freq=850
raspberrypihtpc.wordpress.com
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Re: Raspberry Pi: FAQ 2 years 2 days ago #8

  • Josh.43
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After the work put in by some really top-notch people in the forum (most of which is over my head), it feels like there is a sweet spot for non-over-volted, xbmc-geared configurations

Specifically, the talk around the correlation:
No. ARM, SDRAM and GPU each have their own PLLs can can be unrelated frequencies.
The GPU core, h264, v3d and isp share a PLL, so need to have related frequencies.

Looking at the code, the PLL will be set to:
pll_freq = core_freq * 2^n, for smallest n satisfying pll_freq > 600MHz.

GPU core, h264, v3d and isp should all be integer divisors of PLL freq.
So if core_freq=480, then pll_freq=960. That would allow a v3d_freq of 320 with an integer divider.

Getting the individual numbers as high as possible won't bring as much performance as tuning them to work together.
RasPi, Lego case, OpenELEC, arm_freq=850
raspberrypihtpc.wordpress.com
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Re: Raspberry Pi: FAQ 2 years 2 days ago #9

  • gunja99
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Well I do all of the gpu stuff as one with gpu_freq. I don't do them individually, so they'll match. If you're going to do them individually with core_freq, h264_freq, isp_freq, and v3d_freq instead of just gpu_freq then yes you should have them matching in the multiples listed.

TBH the gpu can cope with the videos I through at them (it's designed for HD video, sooo....), it's the CPU (arm_freq), and the SDRAM that'll make most difference to the performance...

(I think ;))
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Re: Raspberry Pi: FAQ 2 years 2 days ago #10

  • lrusak
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gunja99 wrote:
If u want tested config overclocks:


arm_freq=850
gpu_freq=325
sdram_freq=425

(How on earth u get ur sdram to 600 lsuruk?! U must have an uber pi!) U done that without overvolting?

Honestly I don't know. There is no way of knowing if these values are doing anything really. The only thing you can check it /proc/cpuinfo and check the bogomips which I guess relates to the arm_freq. My bogomips do change with different values so that seems to work.

My other RPi does not overclock like this one. If I put the same sd card in it it will not boot.

I just don't know
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Re: Raspberry Pi: FAQ 2 years 2 days ago #11

  • gunja99
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Must be a lucky boy. Yes the bogomips applies to the arm_freq (normally reported just under what u set), same as a desktop CPU, etc.

Should try and find my other pi, wonder where it is.... heh

I got one from RS, and one from Element14, so maybe two different manus will produce different results.
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Re: Raspberry Pi: FAQ 2 years 2 days ago #12

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gunja99 wrote:
I got one from RS, and one from Element14, so maybe two different manus will produce different results.
Same here.

My RS one doesn't seem to overclock as well as my Element14 (Newark canada) one does.
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Re: Raspberry Pi: FAQ 2 years 1 day ago #13

  • PaJoe
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For what it's worth: I got my Raspberry Pi from Newark/element14 and so far it seems to like

arm_freq=900
core_freq=450
sdram_freq=450


It also seemed to work well with

arm_freq=800


It doesn't like any changes to gpu_freq ( will not boot).


Most of what we have been currently viewing are dvd/bd rips x.264 (.mp4 .mkv .avi) with AC3 5.1 passthrough. We use samba to get files from either my Kubuntu pc or the hard drive attached to our Asus O'Play Air. I was using the Kindle 3g power cord but have replaced that with Amazon basics 2? amp power supply.

Overclocking and some adjustment to the default skin has made it nice to use. I also like HDMI CEC and using our Samsung remote via "Anynet". I am using a Monoprice 4X1 HDMI 1.3b Certified Switcher w/ Toslink & Digital Coaxial to send the digital signal via optical cable to my receiver that hdmi inputs are already in use. The HDMI CEC works OK going through the switch..

joe
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Re: Raspberry Pi: FAQ 2 years 19 hours ago #14

  • ozong
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Josh.43 wrote:

You must use HDMI, and enable passthrough (Settings > System > Audio Output)
(And, of course, your TV must support either decoding or passing through the raw audio stream)

Hi Josh.43

Can you explain some more? I can not see passthrough settings in (Settings > System > Audio Output).

Anyone knows a god program to convert DTS to AC3?

/Oz

Synology Disk Station DS1511+ | ACER REVO 3700 & Raspberry Pi
OpenELEC Stable - Generic x86_64 4.0.4
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Re: Raspberry Pi: FAQ 2 years 8 hours ago #15

  • winker
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Hi,

You mention using your Samsung "AnyNet" Remote, how did you get this setup and working?

Kind regards,

W
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