H264 Decoding Artifacts - Ghosting & "Wavy" images

Dev Community Apps & Creations
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First and foremost, AWESOME job to those developing this project. 

 

My Plex journey started with the purchase of Synology server (can't transcode) and Samsung BluRay player front end.  BR player UI was WAY SLOW!  Looked into purchasing a new player with dual core hardware and decided to purchase ROKU.  ROKU was great, but it did not support MPEG2, which is most of my media.  I stumbled across the RPi and jumped on it for the price.  Setup was easy and I was off an running in no time.

 

UI wasn't as fast as I would like, but it is very usable and the only real lag is when leaving a library back to the main menu.

 

MPEG2 worked fine on the Pi, but I had interlacing artifacts.  I tried enabling Deinterlace in the RPi, but that didn't seem to remove the interlace artifacts.

 

Next, I bregudgingly embarked on the process of converting MPEG2 media to H264 via Handbrake.  Not only would I save space on my server (BTW, I kept the original files on a backup system), but I didn't really notice any picture quality issues......until testing something I recorded on a HTPC with MPEG2 harware encoders.  All other test conversions I looked at were from my collection of DVDs ripped to VOB format.

 

I initially blamed Handbrake transcoding as the culprit.  However, the video plays fine on a MAC with VLC; zero artifact or ghosting issues.  I then tested the video on a laptop using the Plex App - no artifacts or ghosting.

 

I'm left with the hardware decoding being done on the Pi as the culprit I think.  There is something in the MPEG2 encoding process from HTPC that must be throwing off the decoder on the Pi.  After extensive searching on this forum, the Plex forum and other RPi forums, I was unable to find any hint of H264 decoding issues with the RPi.  I searched for "ghosting", "artifact", etc.

 

For anything I record on the HTPC, the artifacts render the media unwatchable once converted to H264.  Tonight I will pay attention to MPEG2 encoded media from the HTPC to see if the same artifacts are present.

 

Does anyone have any ideas?

 

RPi Model B

Rasplex 0.2.2 (no overclocking)

PMS 0.9.7.28.33-f80a4a2 (running from Synology DSM)

 

Thanks,

Heed

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Okay, so I have watched the same movie in MPEG2 format.  The ghosting/artifacts are identical.....issue persists.

I've installed the Plex app on the HTPC (Windows XP) and the ghosting/artifacts do not show up when playing the movie in either MPEG2 or H264 format.  The HTPC and livingroom are two different LCDs from two difference manufacturers.  So I can safely eliminate the video, codec and TV as the culprits I think.

At this point, I am left with the decoder on the RPi as the culprit.

It also only appears to occur with recordings from the HTPC under specific circumstances; darker scenes with lighter objects in them.  In the handful of movies that have been converted from my DVD colelction to H264, I haven't seen the ghosting/artifacts.  As a side note, the HTPC has hardware encoders from Hauppauge; PVR-500.  They are old, but I have had no issues with them up to this point.

I'm not smart on the inner-workings of encoders; software or hardware.

I would think that if I take the MPEG2 encoded video and transcode it to H264, that it would eliminate the cause of the ghosting/artifacts.

Is there something that persists in an encoded video when transcoded from one codec to the next??

Are there tweaks/settings for the H264 decoding on the RPi?

In the mean time, I'm going to hit the forums in Handbrake.......

Thanks for any help in advance.

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did you just for the arguments sake try to overclock you pi?

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did you just for the arguments sake try to overclock you pi?

I didn't and don't think that is it, but I'll leave it as a option if I don't find a solution.

I moved the RPi to another LCD TV and the problem is still there, but much less noticeable.

I am starting to wonder if perhaps it is the interraction of the RPi with the TV via HDMI??  A pciture setting "enhancement" on the TV that causes the issue.

Today I will inspect the media information using mediainfo and compare DVD converted files to my HTPC converted files; both as MPEG2 and H264.  I did notice that some traits migrate in the encoding like framerate (depending on Handbrake setting), etc. during a cursory look.

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This may be a RPi firmware issue too… but never noticed this myself.

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This may be a RPi firmware issue too… but never noticed this myself.

Quick update: It does not appear to be a TV setting.  Played with all of those to no avail.

Firmware is not something I was looking into, so I dove into that tonight.  If I understand what I read on the net, that's not something we can do with OpenElec which is what RasPlex is built upon correct?  According to what I read, having the latest version of OpenElec updats the firmware.

uname -a gives: Linux FamRoom 3.6.11 #1 PREEMPT Fri Jun 28 11:31:01 CEST 2013 armv6l GNU/Linux

vcgencmd version gives: Jun  6 2013 18:30:04, Copyright (c) 2012 Broadcom, version e6f0abde032163069972925f175c4a3a5617d46d (clean) (release)

Are these current?

If not, how do I update?

Thanks in advance.

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After using mediainfo to see what is in each encoded video file,  I came away with two thoughts; framerate and interlacing.  For the DVD's I've encoded and watched, they were progressive.  For the HTPC recordings, they were MPEG2 interlaced recordings transcoded into progressive through handbrake.  I did notice that some DVDs had 24p and others had 29p.

After experimenting with framerate, I have eliminated that.

I spent an hour or so digging in both the Handbrake and videohelp.com forums on interlacing and did see some posts on ghosting.

Right now, I have Handbrake cued up with four encodes; Detelicine & Decomb, Detelicine Only, Decomb Only and last Detelecine/Decomb off while preserving interlaced video (tff flag in advanced settings/CLI).  I've already experimented with Deinterlace filter already.

I'll check each of those videos tomorrow.  This is really frustrating. 

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You’re right - the firmware is updated with new releases only. (Expect a new RasPlex version within the next days)

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Just wondering if the new Firmware solved this problem because I am using 9.9.20 and I am still seeing some artifacts on high data rate movies.

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I came to this thread after a search, I'm seeing the same exact thing - direct playing .MKV files from a local thunderbolt hard drive via Plex Home Theater, playing from a mac mini directly to my main setup.

It's hard to pick up on at first, but i started noticing in some dark scenes some VERY faint vertical lines in the image, much more noticable when there is panning from left/right or right/left.   

It also appears as some "waviness" in bright backgrounds, again, when camera movement is introduced.  it's very subtle but if you know what to look for, it's there.

I assumed it was something related to my mac mini's video card.   The closest thing I can equate it to is how scaling artifacts looked on old dvd players downconverting 480p anamorphic discs to 4:3 televisions (obviously not nearly as bad as that, but it reminded me of it).

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Did you guys try to adjust refresh rate to video framerate (in the playback options iirc).

I know this is working properly in the current code base, just not sure if this was in 9.9.20 already ... but might be worth a try :)

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Smarks - I never reached a resolution.  To eliminate the HDMI cable, I went and purchased a new one.  I am still firmly convinced that this issues relies with the RPi and how it decodes.  I can play the same video on different computers (PC/WinXP w/Plex App, Mac OSX w/Plex App) with the ghosting artifacts not present.  I only see this on the RPi.

Oleus - I have not experienced this issue when using the Plex App on my MacOSX Laptop (or PC for that matter).  I think my issue is directly linked to the RPi and content I record from my PC DVR (BeyondTV w/MPG2 Hardware Encoders).

Although I really like the RPi form factor and it's utility, I think I will ultimately go the route of the Mac Mini.  I've been looking at used Mac Mini's recently.

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That is an interesting issue, I have never noticed that on a movie.

Would you have a sample or a video that you could share so that we can visualize what you are talking about ?

I would like to see if i can reproduce that :)

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I’ve been noticing ghosting in some movies, 1080P while using plex. Is this still an issue with newest version? It seems so. Mainly darker scenes with a lot of movement. Are there any settings I can change on plex server or in the app for my iphone in casting to help get rid of the ghosting?

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@jnburtman said:
I’ve been noticing ghosting in some movies, 1080P while using plex. Is this still an issue with newest version? It seems so. Mainly darker scenes with a lot of movement. Are there any settings I can change on plex server or in the app for my iphone in casting to help get rid of the ghosting?

Sounds like the iPhone app is sending the wrong quality settings with the cast. If you use the regular remote portion of the iphone app to play the movie, do you still have the ghosting?

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I’m getting this issue on 100% of video (mostly h264) I play on Plex to my Android TV Mi Box 3 using the built-in Chromecast functionality. When I play these on a PC, or even over the network with VLC from the exact same box and TV it doesn’t happen.

So it’s definitely the combination of Plex and certain devices, possibly certain hardware decoders?

Here is a good example of the issue. It’s most visible in dark scenes with high contrast. In this example you can clearly see the prior frame (possibly more than one frame back actually). This causes a muddy image and very distorted action.

So to reiterate, it’s not the video file. It’s not the TV or connecting equipment - these all work fine in any other combination. But Plex and my device together result in this issue.

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