[AppleTV] Broadcom Crystal HD stuttering playback on Apple TV?

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_saint_ Offline
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Post: #181
_saint_ Wrote:[snip]
I presume I need to set-up some custom modelines in my xorg.conf to resolve get the 50 and 60Hz modes back?

My xorg log file says:

(--) NVIDIA(0): Connected display device(s) on GeForce Go 7300 at PCI:1:0:0:
(--) NVIDIA(0): PIO PDP-R06 (DFP-0)
(--) NVIDIA(0): PIO PDP-R06 (DFP-0): 165.0 MHz maximum pixel clock
(--) NVIDIA(0): PIO PDP-R06 (DFP-0): Internal Single Link TMDS
(II) NVIDIA(0): Assigned Display Device: DFP-0
(WW) NVIDIA(0):
(WW) NVIDIA(0): No modes were requested; the default mode "nvidia-auto-select"
(WW) NVIDIA(0): will be used as the requested mode.
(WW) NVIDIA(0):
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0): "nvidia-auto-select"
(II) NVIDIA(0): Virtual screen size determined to be 1920 x 1080
(--) NVIDIA(0): DPI set to (50, 50); computed from "UseEdidDpi" X config
(--) NVIDIA(0): option
(==) NVIDIA(0): Disabling 32-bit ARGB GLX visuals.

Regards

_Saint_

Update on Dharma final release:

I've experimented and it turns out the latest nvidia display driver isn't much (if any) different to the one recommended on the wiki in terms of stability and performance. I'm now back on the latest driver. What seems to make the difference is whether I run the UI in 1080p24 or 50/60i and whether XBMC has to change mode/refresh rate to play the film.

If XBMC needs to switch display mode/refresh rate then this can cause the film to stutter for up to 40 seconds:

Quite often my amp (SPDIF) switches between DTS / DD and DPLII whilst it is stuttering (the audio dropping whilst it does this). Things eventually settle down and I've watched quite a few films all the way through.

These look like sync issues - with the video player, audio player and display mode/refresh rate change code not in sync.

I've spotted a couple of other possible bugs:

- I always have a single green pixel at the top left of the video. I can tweak the overscan settings to move it off the screen however this probably isn't right;

- I have a small problem which I believe has been introduced since the last RC. If I play a film that runs at 25Hz XBMC will change to 1080i@50Hz which is right. It then tries to play the film at 24Hz so it judders. When I bring up the on screen info (holding down menu) it basically says pc:1 and confirms that it's running at 24Hz. Mediainfo confirms that it is 25Hz video. I specifically tested the same video under the previous RC and it worked fine. It may be that something else on my system has changed to cause this however it could be a bug that's been introduced since the last RC.

Also XBMC seems to drop frames and stutter slightly when displaying forced subtitles.

Regards

_Saint_
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Fat_Baba Offline
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Post: #182
I also still have same issues with 10.0 final. And the latest crystal driver

Using Crystalbuntu installed on Internal hd with attached USB Drive (HFS+). I am using the older BCM00012 card.

Here is my log:

http://pastebin.com/4KKLyF9B

Mediainfo:

http://pastebin.com/TtNwNU9C

This is just one file. I have problems with 720 and 1080 as well. Sometimes for 10 minutes no problems and then a few framedrops.

I love XBMX and hope that i am doing something wrong

Big Grin

thanks for al the hard work guys
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_saint_ Offline
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Posts: 13
Joined: Dec 2010
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Post: #183
Fat_Baba Wrote:I also still have same issues with 10.0 final. And the latest crystal driver

Using Crystalbuntu installed on Internal hd with attached USB Drive (HFS+). I am using the older BCM00012 card.

Here is my log:

http://pastebin.com/4KKLyF9B

Mediainfo:

http://pastebin.com/TtNwNU9C

This is just one file. I have problems with 720 and 1080 as well. Sometimes for 10 minutes no problems and then a few framedrops.

I love XBMX and hope that i am doing something wrong

Big Grin

thanks for al the hard work guys

My problem with the framerate (24/25Hz problem) is audio related. If I select the first audio track (which is Italian) the video runs at 25Hz, if I select the second audio track (which is English) the video plays at 24Hz.

Under both circumstances the resolution is changed to 1080i 50Hz which is right.

I have "adjust display refresh rate to match video" set however I don't have "sync playback to display set".

The log file shows that XBMC thinks it should be running at 25fps for both audio streaqms however when you look at the on screen debug information (holding menu down whilst the video is playing) it says 24fps for English and 25fps for Italian.

11:14:18 T:2667690896 M: 66686976 NOTICE: fps: 25.000000, pwidth: 1280, pheight: 720, dwidth: 1280, dheight: 720
11:14:18 T:2667690896 M: 58986496 NOTICE: Display resolution ADJUST : default: 1920x1080 @ 50.00Hz (13)

Bug? or problem with the file?

Also for me sound is broken on Dharma which I believe is the root cause of all my video stuttering and performance problems. I've just watched a 720p film this morning and it took over a minute for the sound to settle down - switching between DTS and DPLII.and coughing and splutting. I'm using pass-through SPDIF so XBMC should just be passing the audio through to my amp with no processing.

I suspect these issues will come out in the wash eventually.

Regards

_Saint_
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_saint_ Offline
Junior Member
Posts: 13
Joined: Dec 2010
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Post: #184
_saint_ Wrote:Also for me sound is broken on Dharma which I believe is the root cause of all my video stuttering and performance problems. I've just watched a 720p film this morning and it took over a minute for the sound to settle down - switching between DTS and DPLII.and coughing and splutting. I'm using pass-through SPDIF so XBMC should just be passing the audio through to my amp with no processing.

On further investigation it looks memory related which isn't a surprise given the ATV only has 256Mb RAM.

I noticed that the films that stuttered the most when starting up also had heavy internal hard drive use at the same time. The root cause of this being the swap file being used (growing by up to 100Mb).

To cut a long story short I've changed the swappiness setting to 0 on my system which seems to have helped reduce the impact on the swap file.

Devs - are there any other settings I can tweak to reduce the memory usage. I'm also using DDS, etc?

PS The 24/25Hz issue reported above looks like a bug to me - what should I do next?

Regards

_Saint_
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