Strange Artifacts in Outerspace and Underwater Scenes

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MikeEckman
Posts: 10
Joined: Fri Sep 18, 2009 2:14 am

Strange Artifacts in Outerspace and Underwater Scenes

Post by MikeEckman »

I have been using Handbrake for a while, and feel I have a good grasp of the basic features. I have converted over 500 of my DVDs to the MKV container using h.264 as the video codec and I usually use Dolby or DTS passthru for Audio.

Recently, Ive become endoding my Blu-Rays in 1080p resolution with auto-crop on. I usually leave all the default settings on, and change the RF quality slider to 18 for most movies. I am having a problem that I dont know how to solve and was hoping someone could give me some advice. I know there are a lot of advanced settings, but I dont understand any of them.

Last night, I encoded Blu-Rays of U-571 and The Hunt for Red October (both submarine movies with a lot of underwater shots). In high detail scenes, I am very happy with the picture quality of the output file, but something I notice in both of these movies (and Ive seen it in some space moves like The Fifth Element) is that when there is a scene showing alot of the same color (like underwater or outerspace), after a few seconds, these blurry blobs fade in out of nowhere. If the scene stays the same for several seconds, the blobs will disappear on their own after a few seconds, but they will come back if the scene doesnt change too much. If the scene changes to something else, or something with detail moves through the space where the blob is, the blobs go away.

I have a rudimentary understanding of video compression and I assume this has something to do with the codec compressing similar video to save space, but my question is, how do I avoid this? I am sure this has a name, but I dont know the technical name of what this type of artifacting is.

To summarize, I am using the MKV container on Handbrake 0.9.5 (Ive seen this on previous builds though) using h.264 video. I leave all the default settings, and set the slider to 18. Ive tried different values, but even the difference between RF 20 and RF 18 results in a significantly larger output size. For example, Hunt for Red October resulted in a ~15GB MKV. I dont mind larger file sizes, but the original Blu-RAY rip was around 32 GB, and if I have to increase the file size much more, I might as well just use the original M2TS file and not bother with Handbrake.

Sorry for the long post, and also sorry if this has been covered before, but I dont have the technicial knowledge of what type of problem I even have and a search result here didnt return anything that made sense to me.
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Rodeo
HandBrake Team
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Joined: Tue Mar 03, 2009 8:55 pm

Re: Strange Artifacts in Outerspace and Underwater Scenes

Post by Rodeo »

Sounds more like a decoding problem (possibly a known bug). Are these Blu-Rays H.264? You might want to try a nightly build (see the forum announcement).
MikeEckman
Posts: 10
Joined: Fri Sep 18, 2009 2:14 am

Re: Strange Artifacts in Outerspace and Underwater Scenes

Post by MikeEckman »

Thanks for the reply, but I guess I was hoping for more information on how to prevent this.

Im no expert, but I cant believe this is a decoding problem. I can see these artifacts regardless of how I play the files. I see them using VLC on my Windows 7 desktop, and I see the exact same artifacts when playing them back in XBMC on my Home Theater PC.

I guess I can just live with them, just disappointed because I was hoping I could get near-source quality for my movies.
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Rodeo
HandBrake Team
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Joined: Tue Mar 03, 2009 8:55 pm

Re: Strange Artifacts in Outerspace and Underwater Scenes

Post by Rodeo »

MikeEckman wrote:Im no expert, but I cant believe this is a decoding problem. I can see these artifacts regardless of how I play the files. I see them using VLC on my Windows 7 desktop, and I see the exact same artifacts when playing them back in XBMC on my Home Theater PC.
Where did I mention VLC or XBMC? It might be a known decoding bug in HandBrake (you know, before it encodes your video, it may have to decode the source - does that makes any sense?).
MikeEckman wrote:Thanks for the reply, but I guess I was hoping for more information on how to prevent this.
Did you answer my question or bother to try a nightly build as suggested?
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