2011-09-18, 17:31
Recently I've upgraded from AppleTV with CrystalUbuntu to Zotac ZBOX
Here's my setup
Zotac ZBOXHD-ID11-E (Atom D510 + ION2, 2GB RAM) running official XBMC Live 10.1 release from XBMC.org
XBMC Live package on USB (tried Internal HDD Install with the same results)
Audio connected to Pioneer receiver via optical output
Video connected to Panasonic plasma, 24p capable (tried both 1080p60 and 1080p24 modes)
I've installed XBMC Live Dharma package and found out that it has EXACTLY the same issue that I've experienced on my aTV setup - slight judder of image when subtitles appear on the screen.
It usually starts with first line of subtitle in the movie, and then repeats often when text appears after prolonged time of absence.
Though it is less noticeable than on Apple TV (due to more powerfull hardware) and I guess you won't notice it on some C2D+ systems, but it is there on Atom-based PCs.
The funny thing is that it doesn't even causes registered framedrops (got the Codec Info turned on) - just "PC=" string changes from 24 to NONE (that's when judder occurs) and back.
I've read here http://forum.xbmc.org/showthread.php?tid=77014 that PC parameter stands for "Pattern Correction" and it may have something to do with timestamps in file.
But when I turn subtitles off - the video runs smooth. I was able to reproduce this bug on every linux\live system I could get my hands on. And it happens to various deegree on every MKV file I got.
I've tried both 60Hz and 24Hz mode, Sync Video to Display off and on (with every option listed) and even latest Nightly builds - the bug is still there.
The reason I'm sure that it is XBMC Live issue is that I've installed Win7 on my Zotac ZBOX and everything runs smooth on Windows version of Dharma! Same files - no judder!
And it is not only me - I've got reports from other people experiencing the same bug (on Apple TV, but it doesn't matter, because CrystalUbuntu is based on XBMC Live distro - as i said, the bug is the same on any devices)
Here are the links to those posts:
http://forum.xbmc.org/showthread.php?tid=89432
Here's my XBMC log with debug on (started test video file on 17:25:01)
http://pastebin.com/t6ugq7xS
Here's the Media Info of the test file (first 5 min of Avatar 1080p rip)
http://pastebin.com/T8fquuds
And here's the test file itself (520 Mb)
http://dl.dropbox.com/u/420380/test.mkv
The most noticable judder can be found at 0:39 with first line of subtitles appearing.
It really surprises me that no one notices this issue on Dharma! And the bug is still exists on the latest nightlies. Or maybe I am missing something here?
BTW, the bug isn't present on early pre-Dharma build I've tried on Apple TV.
I'd love to use lightweight XBMC Live distro on my new ION HTPC, but it is no go with framedrops on subtitles ;(
I think it is the issue of VDPAU implementation in Linux, since the Dharma works fine on Windows.
I'm not a developer and do not familiar with open sourse projects, so can someone post a bug report somewhere about it?
Thanks a lot in advance, guys!
Here's my setup
Zotac ZBOXHD-ID11-E (Atom D510 + ION2, 2GB RAM) running official XBMC Live 10.1 release from XBMC.org
XBMC Live package on USB (tried Internal HDD Install with the same results)
Audio connected to Pioneer receiver via optical output
Video connected to Panasonic plasma, 24p capable (tried both 1080p60 and 1080p24 modes)
I've installed XBMC Live Dharma package and found out that it has EXACTLY the same issue that I've experienced on my aTV setup - slight judder of image when subtitles appear on the screen.
It usually starts with first line of subtitle in the movie, and then repeats often when text appears after prolonged time of absence.
Though it is less noticeable than on Apple TV (due to more powerfull hardware) and I guess you won't notice it on some C2D+ systems, but it is there on Atom-based PCs.
The funny thing is that it doesn't even causes registered framedrops (got the Codec Info turned on) - just "PC=" string changes from 24 to NONE (that's when judder occurs) and back.
I've read here http://forum.xbmc.org/showthread.php?tid=77014 that PC parameter stands for "Pattern Correction" and it may have something to do with timestamps in file.
But when I turn subtitles off - the video runs smooth. I was able to reproduce this bug on every linux\live system I could get my hands on. And it happens to various deegree on every MKV file I got.
I've tried both 60Hz and 24Hz mode, Sync Video to Display off and on (with every option listed) and even latest Nightly builds - the bug is still there.
The reason I'm sure that it is XBMC Live issue is that I've installed Win7 on my Zotac ZBOX and everything runs smooth on Windows version of Dharma! Same files - no judder!
And it is not only me - I've got reports from other people experiencing the same bug (on Apple TV, but it doesn't matter, because CrystalUbuntu is based on XBMC Live distro - as i said, the bug is the same on any devices)
Here are the links to those posts:
http://forum.xbmc.org/showthread.php?tid=89432
Here's my XBMC log with debug on (started test video file on 17:25:01)
http://pastebin.com/t6ugq7xS
Here's the Media Info of the test file (first 5 min of Avatar 1080p rip)
http://pastebin.com/T8fquuds
And here's the test file itself (520 Mb)
http://dl.dropbox.com/u/420380/test.mkv
The most noticable judder can be found at 0:39 with first line of subtitles appearing.
It really surprises me that no one notices this issue on Dharma! And the bug is still exists on the latest nightlies. Or maybe I am missing something here?
BTW, the bug isn't present on early pre-Dharma build I've tried on Apple TV.
I'd love to use lightweight XBMC Live distro on my new ION HTPC, but it is no go with framedrops on subtitles ;(
I think it is the issue of VDPAU implementation in Linux, since the Dharma works fine on Windows.
I'm not a developer and do not familiar with open sourse projects, so can someone post a bug report somewhere about it?
Thanks a lot in advance, guys!