Grainy MKVs |

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Grainy MKVs |
Jun 28 2010, 02:20 AM
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#1
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WDTV USER ![]() Group: Members |
MKVs appear very grainy, with tiny artifacts displayed all over the image. The degree of graininess varies depending on which MKV I'm watching, and from what I've been able to tell, it depends on the file size of the MKV itself. MP4s display beautifully without any grain or artifacts. Also, when I use gotSent to convert a grainy MKV into an MP4, the MP4 version looks great.
Is there a setting or something I can set to reduce this effect? What can I do? |
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Jun 28 2010, 02:20 AM
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SITE SUPPORT Group: Bot |
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Jun 28 2010, 10:09 AM
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#2
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WDTV GEEK Group: Moderator |
Well, there's something new every day... (IMG:style_emoticons/default/rolleyes.gif) You didn't specifically mention it, but I assume artefacts/graininess decreases as MKV file size increases? But the very same grainy MKV becomes crystal clear on converting to MP4?
If so, can't be the TV connection since MP4s play back fine. All I can think of is that gotSent is perhaps re-encoding the original video (which the player can't seem to handle properly) somehow and making it more palatable for the hardware. How long on average does it take to finish its job per file? Does it indicate a simple demuxing/remuxing process or is there a hint of re-encoding being carried out anywhere? You can also compare the MKVs and MP4s with MediaInfo and see what exactly has been done to the audio/video streams post conversion. Besides that... how is the player connected to the TV? Via HDMI? Do try different resolution settings (especially if it is set to Auto) and see if that helps any. Try and match the file's resolution, the TV's max. resolution etc. |
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Jun 28 2010, 12:15 PM
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#3
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WDTV USER ![]() Group: Members |
I am only guessing about the file size correlation. I only have about 10 mkvs, and just from what I've noticed, the smaller ones look better than the larger one.
From afar, the graininess sort of looks like an unclear antenna signal. When I get up close to the tv, i see lots of tiny artifacts all over. Also, with some darker areas, I can see clear pixelation, like swaths of a single color with hard edges to the next color, instead of gradients. Yes, the very same file converted to mp4 looks fine. Converting an MKV to an MP4 takes about 12 hours to complete for some reason. The reason I bought this device was because I was tired of converting my MKVs to MP4s to play on my xbox, since it takes so long. Also, I don't have a high success rate with the conversion - often, the conversion creates a broken file after 12 hours of encoding. When I get home, I'll check out MediaInfo and look at the details of the MKVs that play fine with ones that dont. I tried all WDTV setting options (Auto, and all the refresh rates of the 1080p options), and I still get the artifacts and grain. Btw, the box is connected via HDMI. |
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Jun 29 2010, 12:02 PM
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#4
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WDTV GEEK Group: Moderator |
12 hours = definitely re-encoding being carried out. Since re-encoding always causes quality loss to a smaller or larger extent, I guess maybe the original MKVs are not fully compliant with the specs of the player. Maybe the reframe count is too high, or maybe CABAC is used or something else that the player doesn't handle too well, which re-encoding to MP4 then removes/fixes.
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