[mythtv-users] Arm Based Frontend

Sat Apr 19 18:53:32 UTC 2014

Hello all,

I know, here we go again, another question about low power front ends.

Well, not really.  I ran across some notes that said there was now VDPAU for
the sunxi/mali400 chip devices.  It seems to sit on top of the "binary blob"
drivers.

So, I fired up my trusty hackberry board and installed Fedora 20, got it
completely up to date with the latest kernel off of the sunxi site.
3.4.79ish.  Followed all the instructions on installing "binary blob"
drivers and fbturbo and finally VDPAU.

Then, being a masochist I downloaded the latest fixes .027 and went about
compiling mythtv.  Yes on the hackberry itself, I have not yet fiddled with
cross compiling.  I only compiled libs programs and yes it took forever.
There was a syntax error in the ffmpeg portion.  I found a patch for it in
the ffmpeg forums and then it compiled ok.  In fact everything compiled ok.

So, I fired up mythfrontend.  Damned if it did not come up.  I set video
play back to vdpau slim, audio to the hdmi device and went to play back a
recording.  I chose a very low file for my first test.  A recording of "It
takes a thief".  After some crackling, it played.  Yep it played.  Not
perfectly.  Not usably, but it played.  Oddly it played too fast as if I had
chosen to play it back at maybe 1.5 times normal.  There was some video
tearing but the VDPAU stuff is still very new, perhaps that will change.  I
can't get the OSD to appear, not sure why.  Choosing OpenGL for the painter
gives a black screen (I fell back to qt).  Oh and playback continued with
30-50 percent idle processor.  Audio seems to be sketchy, I will try it with
the non-hdmi connector to see if that makes a difference. 

Playing back higher quality digital programs produced similar results.
Attempts to playback recordings from my HDPVR resulted in a ball of
scrambled pixels in the center of the screen.

Anyway, I *think* this may be the farthest anyone has gotten with one of
these boards and I just wanted to share my experience.

Small update, I got past the missing OSD by setting an environment variable.

I believe this to be the source of being unable to play recordings from my
HDPVR (a message coming from the VDPAU layer I guess) :

[VDPAU SUNXI] We can't decode interlaced frames yet! Sorry

And this may be the root of the "too fast" playback issue:

2014-04-19 14:25:07.913903 I  VidOutVDPAU: Enabled deinterlacing.

2014-04-19 14:25:07.914129 E  VSYNC: DRMVideoSync: VBlank ioctl did not
work, unimplemented in this driver?

2014-04-19 14:25:07.918892 I  Player(0): Video timing method: RTC

2014-04-19 14:25:07.919016 I  Player(0): Display Refresh Rate: 60.013 Video
Frame Rate: 29.970

2014-04-19 14:25:07.919092 I  Player(0): SetFrameInterval ps:1 scan:1

2014-04-19 14:25:07.924087 I  playCtx: StartPlaying(): took 0 ms to start
player.

2014-04-19 14:25:07.924217 I  TV: Created player.

2014-04-19 14:25:07.924393 I  TV: StartPlayer(0, WatchingPreRecorded, main)
-- end ok

2014-04-19 14:25:07.925670 I  TV: Changing from None to WatchingPreRecorded

2014-04-19 14:25:07.938901 I  VidOutVDPAU: Created VDPAU decoder (2 ref
frames)

2014-04-19 14:25:07.942618 I  TV: DrawUnusedRects() -- begin

2014-04-19 14:25:07.942740 I  TV: DrawUnusedRects() -- end

2014-04-19 14:25:07.943057 I  TV: Main UI disabled.

2014-04-19 14:25:07.943125 I  TV: HandleStateChange(0) -- end

2014-04-19 14:25:07.943454 I  TV: tv->Playback() -- end

2014-04-19 14:25:07.943511 I  TV: Entering main playback loop.

2014-04-19 14:25:08.005643 I  Player(0): Waiting for video buffers...

2014-04-19 14:25:08.023848 I  AFD: EIA-708 caption service #1 is in the
Undetermined language.

2014-04-19 14:25:08.028406 I  Player(0): Enabled deinterlacing

2014-04-19 14:25:08.058360 I  VDPAU: Added 2 output surfaces (total 4, max
4)

2014-04-19 14:25:08.058196 I  Dec: Selected track #1 (type 5) in the
Undetermined language(7695972)

2014-04-19 14:25:10.065231 I  Player(0): Video is 3.33668 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.065720 I  Player(0): Video is 3.44655 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.066074 I  Player(0): Video is 3.27419 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.220057 I  Player(0): Video is 3.16336 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.220476 I  Player(0): Video is 3.24165 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.220844 I  Player(0): Video is 3.05311 frames behind
audio (too slow), dropping frame to catch up.

2014-04-19 14:25:10.738573 I  Player(0): FPS:   46.18 Mean: 21654 Std.Dev:
7665 CPUs: 100% 

2014-04-19 14:25:13.783087 I  Player(0): FPS:   39.11 Mean: 25571 Std.Dev:
7414 CPUs: 66%

If I interpret this correctly it is attempting to display frames at 60FPS
and failing..

If anyone has a clue how I can hack a change to this to force 29.97 I would
love to try it.

Tim

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