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Is mjpegcorrect() still needed in Avisynth 2.5?

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I think so... but do you know if a version for avisynth 2.5 exists? And if not, how is it possible to make the same luma corrections using other filters? Thanks Lucio P.S. Is there an Huffyuv version for YV12? I did read the thread but find nothing...

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Wedge

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Registration: 11.19.2003
01.03.24 - 16:03:23
Message # 1
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

One of the last questions in the YV12 faq!

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Sundevil

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Registration: 04.15.2003
01.03.24 - 16:10:12
Message # 2
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

- Don't double post! - Use search. :readfaq: The other thread has been removed.

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-Sgt.

Sgt

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Registration: 12.30.2002
01.03.24 - 16:21:11
Message # 3
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

- MjpegCorrect seem to be a luma-scaling filter - this should not be necessary at any time. Use historgram to check your color ranges - if you run it in YV12 mode it should not enter the "brown/yellow" areas, but black should lie at the bottom of this range. See the capture guide on the main doom9 page for more info. - Using MJPEG it doesn't matter what format you capture in - this will have no impact on the speed you get, when decoding it.

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Yale Dakar Club Member #7

YAYO

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Registration: 05.24.2001
01.03.24 - 16:27:35
Message # 4
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

I think the issue is that some mjpeg codecs improperly/inconsistently clip the luma range to 16-235 when encoding/decoding yuy2. is fairly informative. I use the pixel_type parameter in avisource to force rgb decoding and then convert to yuy2 or yv12. Presumably it's slower than mjpegcorrect, but perhaps more accurate? For completeness, decoding picvideo in yuy2 then converting to yv12 does run into the "brown/yellow" areas of histogram. Decoding in rgb then converting to yv12 does not. The morgan codec seems to have the same problem. Edit: coloryuv(levels="pc->tv") should do the same thing as mjpegcorrect, but decoding to rgb seems more accurate to me.

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Jean@ActiveAutowerke

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Registration: 10.01.2001
01.03.24 - 16:33:14
Message # 5
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

@waka: Luma range SHOULD be limited to 16-235. RGB->YUV convertion also produces 16-235 as defined by CCIR 601. When you do this you get overbrighted video.

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DonJuan

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Registration: 02.10.2003
01.03.24 - 16:42:58
Message # 6
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

I phrased that poorly, what I should of said is that on decoding 16-235 is scaled to 0-255(!?!). On encoding 0-255 is clipped to 16-235. At least thats how it seems to work on my system. Decoding in yuy2 using avisynth and resaving in vdub causes the video to get more and more clipped with each iteration.

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J4SON

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Registration: 01.28.2003
01.03.24 - 16:48:48
Message # 7
RE: Is mjpegcorrect() still needed in Avisynth 2.5?

Oh - I haven't experienced this with Morgan MJPEG, but maybe Avid Express exports as RGB.

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dadhania

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Registration: 10.24.2003
01.03.24 - 16:53:00
Message # 8
RE: Is mjpegcorrect() still needed in Avisynth 2.5?
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