Limiter
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The standard known as Rec.601 or [[Wikipedia:Rec._601|CCIR-601]] (''Studio Encoding Parameters of Digital Television...'') defines standard quantization levels: for luminance, black is '''16''' and peak white is '''235'''. This is the normal luminance range. For chrominance, the range is '''16''' to '''240''', or 128±112. "The signal may occasionally excurse beyond" these ranges according to Rec.601.<sup>[http://www.itu.int/rec/R-REC-BT.601/ BT.601-7] (Annex 1, Table 3)</sup> | The standard known as Rec.601 or [[Wikipedia:Rec._601|CCIR-601]] (''Studio Encoding Parameters of Digital Television...'') defines standard quantization levels: for luminance, black is '''16''' and peak white is '''235'''. This is the normal luminance range. For chrominance, the range is '''16''' to '''240''', or 128±112. "The signal may occasionally excurse beyond" these ranges according to Rec.601.<sup>[http://www.itu.int/rec/R-REC-BT.601/ BT.601-7] (Annex 1, Table 3)</sup> | ||
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'''Limiter''' can also colorize out-of-range pixels (with {{FuncArg|show}}) to warn of a potential problem. See the [[#Examples|example images]] below. Naturally, this option should not be enabled for final output. | '''Limiter''' can also colorize out-of-range pixels (with {{FuncArg|show}}) to warn of a potential problem. See the [[#Examples|example images]] below. Naturally, this option should not be enabled for final output. | ||
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__TOC__ | __TOC__ | ||
== Syntax and Parameters == | == Syntax and Parameters == | ||
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{{Template:FuncDef | {{Template:FuncDef | ||
|Limiter(clip ''clip'' [, int ''min_luma'', int ''max_luma'', int ''min_chroma'', int ''max_chroma'', string show ] ) | |Limiter(clip ''clip'' [, int ''min_luma'', int ''max_luma'', int ''min_chroma'', int ''max_chroma'', string show ] ) | ||
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| {{BoldColor|#FF00FF|120|♦}} magenta | | {{BoldColor|#FF00FF|120|♦}} magenta | ||
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[[FFmpegSource|FFmpegSource2]]("[http://www.sintel.org/ sintel].mp4") | [[FFmpegSource|FFmpegSource2]]("[http://www.sintel.org/ sintel].mp4") | ||
[[Trim]](4685, 4685) | [[Trim]](4685, 4685) | ||
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# 2. Exaggerated luma and chroma range | # 2. Exaggerated luma and chroma range | ||
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[[Levels]](16, 1.0, 255-16, 0, 255, coring=false) | [[Levels]](16, 1.0, 255-16, 0, 255, coring=false) | ||
[[Tweak]](sat=2.0, coring=false) | [[Tweak]](sat=2.0, coring=false) | ||
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ColorYUV(analyze=true) | ColorYUV(analyze=true) | ||
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|[[File:Limit_Ex07a.png|768px]] | |[[File:Limit_Ex07a.png|768px]] | ||
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== Changes == | == Changes == | ||
Revision as of 10:19, 28 February 2016
The standard known as Rec.601 or CCIR-601 (Studio Encoding Parameters of Digital Television...) defines standard quantization levels: for luminance, black is 16 and peak white is 235. This is the normal luminance range. For chrominance, the range is 16 to 240, or 128±112. "The signal may occasionally excurse beyond" these ranges according to Rec.601.BT.601-7 (Annex 1, Table 3)
Luminance or chrominance values outside their ranges are known to cause problems with some TV sets, so Limiter was created to clip them (or clamp them - both terms are used) to the ranges [min_luma, max_luma] and [min_chroma, max_chroma], which you may specify, but by default are the Rec.601 values listed above.
Limiter can also colorize out-of-range pixels (with show) to warn of a potential problem. See the example images below. Naturally, this option should not be enabled for final output.
Contents |
Syntax and Parameters
Limiter(clip clip [, int min_luma, int max_luma, int min_chroma, int max_chroma, string show ] )
- clip clip = (required)
- Source clip. YUV only.
- int min_luma = 16
- Y (luma) lower bound.
- int max_luma = 235
- Y (luma) upper bound.
- int min_chroma = 16
- U & V (chroma) lower bound.
- int max_chroma = 240
- U & V (chroma) upper bound.
- string show = (empty)
- Colorizes the pixels outside the specified [min_X, max_X] range.
- If set, show must take one of the following values:
show Effect "luma" colorizes out of bound luma "luma_grey" colorizes out of bound luma, and makes the remaining pixels grey "chroma" colorizes out of bound chroma "chroma_grey" colorizes out of bound chroma, and makes the remaining pixels grey
Pixel Condition Colorization show="luma" show="luma_grey" Yj < min_luma ♦ red (pj) ♦ red (pj) Yj > max_luma ♦ green (pj) ♦ green (pj) Yj < min_luma and Yk > max_luma ♦ yellow (pj and pk) ♦ puke (pj) ♦ olive (pk) show="chroma" show="chroma_grey" U < min_chroma ♦ yellow ♦ yellow U > max_chroma ♦ blue V < min_chroma ♦ cyan V > max_chroma ♦ red U < min_chroma and V < min_chroma ♦ green U > max_chroma and V < min_chroma ♦ teal U < min_chroma and V > max_chroma ♦ orange U > max_chroma and V > max_chroma ♦ magenta
Examples
# 1. Original image FFmpegSource2("sintel.mp4") Trim(4685, 4685) # 2. Exaggerated luma and chroma range Levels(16, 1.0, 255-16, 0, 255, coring=false) Tweak(sat=2.0, coring=false) # (insert Limiter here) ColorYUV(analyze=true)
# 3. Limiter("luma") [...] Limiter(16, 235, 16, 240, "luma") ColorYUV(analyze=true)
# 4. Limiter("luma_grey") [...] Limiter(16, 235, 16, 240, "luma_grey") ColorYUV(analyze=true)
# 5. Limiter("chroma") [...] Limiter(16, 235, 16, 240, "chroma") ColorYUV(analyze=true)
# 6. Limiter("chroma_grey") [...] Limiter(16, 235, 16, 240, "chroma_grey") ColorYUV(analyze=true)
# 7. Putting it all together [...] StackHorizontal( \ Last \ , StackVertical( \ Histogram("levels", 0.5).Crop(Width, 0, 256, 256).AddBorders(0, 0, 0, Height/2-256) \ , Histogram("color2" ).Crop(Width, 0, 256, 256).AddBorders(0, 0, 0, Height/2-256) \ ) \ , StackVertical( \ BicubicResize(Width/2, Height/2).Limiter(16, 235, 16, 240, "luma_grey") \ , BicubicResize(Width/2, Height/2).Limiter(16, 235, 16, 240, "chroma_grey") \ ) \ )
Changes
| v2.60 | Added support for YV24. |
| v2.56 | Added show to show out of bound luma/chroma. |
