GUI setting option to disable inloop deblocking (skip loop filter) for H.264 content?
#1
Question 
Hi,
I build my HTPC especially for playing highdef content on my FullHD display. While playing a 720p h264 mkv file is no problem, 1080p does hardly work if the bitrate goes above ~8mbit. I tried it with XBMC, mplayer and vlc, nothing worked so far.

I did a little researche in the ubuntu forum and found this:
http://ubuntuforums.org/showthread.php?t=629701

It describes how to disable the loopback (filter?) to gain a speedup in decoding h264. (Of course you will lose some quality)

I tried it with the mplayer and it works. Now, is there a possibility to use these parameters in xbmc for decoding 1080p h264 content? I added the parameters to the mplayer.conf file, but they did not have any effect.

My system:
Athon64 X2 5000
Abit AN-M2HD
Onboard Geforce 7050


Jack
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#2
XBMC for linux doesn't use mplayer.
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Image
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#3
...and I think you mean "inloop" (or "in-loop") filter, not "loopback" filter.

XBMC for Linux uses XBMC's own in-house developed video-player that we call "DVDPlayer" that is based on FFmpeg.

PS! FYI; Elan tested disabling "inloop" filtering for FFmpeg inside DVDPlayer in XBMC for Mac OS X and it did not yeild much speed gain (only one frame per socond or so IIRC).
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#4
jmarshall Wrote:XBMC for linux doesn't use mplayer.
That explains why mplayer.conf is not working Wink

@Gamester17
you are right, its called inloop. I don't know where I read "loopback".

The available FFmpeg options for this are called:
"skiploopfilter=none"
"skiploopfilter=bidir"
"skiploopfilter=nonref
"skiploopfilter=all"

I just checkt XBMC's DVDPlayer source code myself, the option is already in there but commented out. It says that the option has nearly no impact on the performance cause of the multi-threading patch that XBMC uses ;(

It seems that I have to wait for a big ffmpeg update.
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#5
I can't play all 1080p content on a Core 2 [email protected] which is probably a bit (~5%) faster than the x2 5000: http://www23.tomshardware.com/cpu_2007.h...&chart=431 shows a 2.13GHz Core 2 Duo basically even with an x2 5000.

I'd be interested to hear if you manage to improve performance, but as far as I know, your CPU may not be fast enough.
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#6
Lightbulb 
I recently discovered that adding lavdopts=skiploopfilter=bidir, or lavdopts=skiploopfilter=all, or lavdopts=skiploopfilter=nonref to the mplayer.conf file turns off different deblocking modes in MPlayer.

My question is: does this affect all codecs or are there only certain ones that this affects? Ideally I would like to have this setting only affect H.264 playback, and all other video playback be unaffected...

Also, is there any way we can get this added to the GUI, so the setting can be changed very quickly? This setting drastically improves the playback of H.264 files encoded with the deblocking filter with various changes in quality. the "bidir" setting seems to look the best, while still reducing dropped frames by more than 50%!!! If the file has no deblocking, then it is more likely it will playback better, with no reduced quality.

If this were a GUI setting...

Skip Deblocking:
+ None (Default)
+ BiDir
+ NonRef
+ All (BiDir + NonRef)

Easy as that... half the H.264 playback issues solved with a simple little setting provided conveniently to the user! Let's push this!
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#7
I think you meant "lavcopts" Smile

But, to answer your question, I'm pretty sure this will affect everything that's decoded using libavcodec (which is a part of ffmpeg.)

http://www.mplayerhq.hu/DOCS/HTML/en/men...codec.html

**edit**

For MPlayer (in XBMC for Xbox) you can create conf files that are used for specific files. If you have moviename.avi, xbmc will look for moviename.avi.conf.
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#8
I'm pretty sure I meant "lavdopts", just like the thread title... IDK... maybe they both do the same thing, but a Google search of "lavdopts" yields 450 results, and "lavcopts" only yields 4.

.conf files for each movie is a little overboard IMO. There's no way to only have this turned on during H.264 playback? I'm sure there's a way -- anything is possible!
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#9
FYI; the "skiploopfilter" option (to disable in-loop deblocking) has been discussed before here:
http://forum.xbmc.org/showthread.php?tid=23969
and here:
http://forum.xbmc.org/showthread.php?tid=32572
and here:
http://forum.xbmc.org/showthread.php?tid=27243

PS! IIRC skiploopfilter currenly only affects H.264 decoding in MPlayer/FFmpeg but check mplayerhq.hu and ffmpeg.org to confirm (e-mail their user-list, not the development-list)
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Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
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#10
Apologies. I originally thought that was a typo as I'd never seen it before. A little research shows the lavdopts are just additional libavcodec debugging parameters. According to the man page, this parameter only applies to H264.
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#11
So, technically, this feature would be a valuable addition to the GUI, wouldn't it? How can we formally make a feature request? I'm sure this wouldn't take any time to program, and would be really beneficial for fellow Xbox+XBMC users...

Sorry if this has been asked before...
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#12
Sure, see the FAQ: http://wiki.xbmc.org/?title=What_is_XBMC...to_XBMC.3F
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#13
Go for it JPSiemer. This should give some bosst for H.264 Decoding.
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#14
Question 
Hi,
Thank you to all involved in XBMC - it's amazing!
I've noticed that my mp4s don't look as good (more pixilated) when playing through xbmc as they do when I'm just using the apple tv - is this a setting that I need to modify? Divx, etc all look the same as through nito tv but the difference on mp4s is quite noticeable.
Blue
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#15
bluewooster Wrote:Hi,
Thank you to all involved in XBMC - it's amazing!
I've noticed that my mp4s don't look as good (more pixilated) when playing through xbmc as they do when I'm just using the apple tv - is this a setting that I need to modify?
Blue

Hi Blue,
there is a file called advancedsettings.xml in /Users/frontrow/Library/Application Support/XBMC/userdata/.
It has an entry called skiploopfilter which seems to does exactly what you see. Removing the entry should give back picture quality but will lead to decreased playback performance.

Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules. If you don't have the time to read them, please don't take the time to post in this forum!
For troubleshooting and bug reporting please make sure you read this first.
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GUI setting option to disable inloop deblocking (skip loop filter) for H.264 content?0