HDR -> SDR tonemapping

Support for my Avisynth filters
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admin
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Re: HDR -> SDR tonemapping

Post by admin » Fri Apr 13, 2018 4:19 pm

It's easiest just to give you the code.

Code: Select all

#include "windows.h"
#include "avisynth.h"
#include "stdio.h"

class DGReinhard : public GenericVideoFilter
{
	float contrast;
	float bright;

public:
	DGReinhard(PClip _child, float _contrast, float _bright, IScriptEnvironment* env) : GenericVideoFilter(_child)
	{
		if (vi.pixel_type != VideoInfo::CS_RGBPS)
		{
			env->ThrowError("DGReinhard: input must be CS_RGBPS");
		}
		contrast = _contrast;
		bright = _bright;
	}
    PVideoFrame __stdcall GetFrame(int n, IScriptEnvironment* env);
};

PVideoFrame __stdcall DGReinhard::GetFrame(int n, IScriptEnvironment* env)
{
    PVideoFrame src = child->GetFrame(n, env);
	PVideoFrame dst = env->NewVideoFrame(vi);

	float *srcpR, *srcpG, *srcpB;
	float *dstpR, *dstpG, *dstpB;

	const int src_pitch = src->GetPitch(PLANAR_R) / 4;
	const int dst_pitch = dst->GetPitch(PLANAR_R) / 4;
	const int row_size = dst->GetRowSize(PLANAR_R);
	const int width = vi.width;
	const int height = dst->GetHeight(PLANAR_R);

	const float offset = (1.0f - contrast) / contrast;
	const float factor = (bright + offset) / bright;

	srcpR = (float *)src->GetReadPtr(PLANAR_R);
	dstpR = (float *)dst->GetWritePtr(PLANAR_R);
	srcpG = (float *)src->GetReadPtr(PLANAR_G);
	dstpG = (float *)dst->GetWritePtr(PLANAR_G);
	srcpB = (float *)src->GetReadPtr(PLANAR_B);
	dstpB = (float *)dst->GetWritePtr(PLANAR_B);
	for (int y = 0; y < height; y++)
	{
		for (int x = 0; x < width; x++)
		{
			dstpR[x] = srcpR[x] / (srcpR[x] + offset) * factor;
			dstpG[x] = srcpG[x] / (srcpG[x] + offset) * factor;
			dstpB[x] = srcpB[x] / (srcpB[x] + offset) * factor;
		}
		srcpR += src_pitch;
		srcpG += src_pitch;
		srcpB += src_pitch;
		dstpR += dst_pitch;
		dstpG += dst_pitch;
		dstpB += dst_pitch;
	}

	return dst;
}

class DGHable : public GenericVideoFilter
{
	float exposure, a, b, c, d, e, f, w;

public:
	DGHable(PClip _child, float _exposure,
		float _a,
		float _b,
		float _c,
		float _d,
		float _e,
		float _f,
		float _w,
		IScriptEnvironment* env) : GenericVideoFilter(_child)
	{
		if (vi.pixel_type != VideoInfo::CS_RGBPS)
		{
			env->ThrowError("DGHable: input must be CS_RGBPS");
		}
		exposure = _exposure;
		a = _a;
		b = _b;
		c = _c;
		d = _d;
		e = _e;
		f = _f;
		w = _w;
	}

	float hable(float in)
	{
		return (in * (in * a + b * c) + d * e) / (in * (in * a + b) + d * f) - e / f;
	}

	PVideoFrame __stdcall GetFrame(int n, IScriptEnvironment* env);
};

PVideoFrame __stdcall DGHable::GetFrame(int n, IScriptEnvironment* env)
{
	PVideoFrame src = child->GetFrame(n, env);
	PVideoFrame dst = env->NewVideoFrame(vi);

	float *srcpR, *srcpG, *srcpB;
	float *dstpR, *dstpG, *dstpB;

	const int src_pitch = src->GetPitch(PLANAR_R) / 4;
	const int dst_pitch = dst->GetPitch(PLANAR_R) / 4;
	const int row_size = dst->GetRowSize(PLANAR_R);
	const int width = vi.width;
	const int height = dst->GetHeight(PLANAR_R);

	srcpR = (float *)src->GetReadPtr(PLANAR_R);
	dstpR = (float *)dst->GetWritePtr(PLANAR_R);
	srcpG = (float *)src->GetReadPtr(PLANAR_G);
	dstpG = (float *)dst->GetWritePtr(PLANAR_G);
	srcpB = (float *)src->GetReadPtr(PLANAR_B);
	dstpB = (float *)dst->GetWritePtr(PLANAR_B);

	float whitescale = 1.0f / hable(w);

	for (int y = 0; y < height; y++)
	{
		for (int x = 0; x < width; x++)
		{
			dstpR[x] = hable(exposure * srcpR[x]) * whitescale;
			dstpG[x] = hable(exposure * srcpG[x]) * whitescale;
			dstpB[x] = hable(exposure * srcpB[x]) * whitescale;
		}
		srcpR += src_pitch;
		srcpG += src_pitch;
		srcpB += src_pitch;
		dstpR += dst_pitch;
		dstpG += dst_pitch;
		dstpB += dst_pitch;
	}

	return dst;
}

AVSValue __cdecl Create_DGReinhard(AVSValue args, void* user_data, IScriptEnvironment* env)
{
	return new DGReinhard(args[0].AsClip(),
		(float)args[1].AsFloat(0.3f),
		(float)args[2].AsFloat(5.0f),
		env);
}

AVSValue __cdecl Create_DGHable(AVSValue args, void* user_data, IScriptEnvironment* env)
{
	return new DGHable(args[0].AsClip(),
		(float)args[1].AsFloat(2.0f),
		(float)args[2].AsFloat(0.15f),
		(float)args[3].AsFloat(0.50f),
		(float)args[4].AsFloat(0.10f),
		(float)args[5].AsFloat(0.20f),
		(float)args[6].AsFloat(0.02f),
		(float)args[7].AsFloat(0.30f),
		(float)args[8].AsFloat(11.20f),
		env);
}

const AVS_Linkage *AVS_linkage = 0;
extern "C" __declspec(dllexport) const char* __stdcall AvisynthPluginInit3(IScriptEnvironment* env, AVS_Linkage* vectors)
{
	AVS_linkage = vectors;
	env->AddFunction("DGReinhard", "c[contrast]f[bright]f", Create_DGReinhard, 0);
	env->AddFunction("DGHable", "c[exposure]f[a]f[b]f[c]f[d]f[e]f[f]f[w]f", Create_DGHable, 0);
	return 0;
}

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admin
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Re: HDR -> SDR tonemapping

Post by admin » Wed Apr 18, 2018 6:55 am

I'm recommending a small change to the Avisynth+ script that improves things a bit. Note the ConvertBits() call:

loadplugin("DGDecodeNV.dll")
loadplugin("DGTonemap.dll")
loadplugin("avsresize.dll")
SetFilterMTMode("z_ConvertFormat", MT_MULTI_INSTANCE) # May not be needed.
DGSource("THE GREAT WALL.dgi",fulldepth=true)
ConvertBits(10) # use 12 for 12-bit
z_ConvertFormat(pixel_type="RGBPS",colorspace_op="2020ncl:st2084:2020:l=>rgb:linear:2020:l", dither_type="none")
# Choose one of these:
DGReinhard()
#DGHable()
z_ConvertFormat(pixel_type="YV12",colorspace_op="rgb:linear:2020:l=>709:709:709:l",dither_type="ordered")
prefetch(4)

gonca
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Re: HDR -> SDR tonemapping

Post by gonca » Wed Apr 18, 2018 3:39 pm

Do you require any testing or comparisons done with the change?

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admin
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Re: HDR -> SDR tonemapping

Post by admin » Wed Apr 18, 2018 4:53 pm

No thank you, gonca, I've tested it and confirmed to my satisfaction that it works a little better. If you stumble across anything, though, please report it.

I got an email from someone thinking there is no difference between fulldepth=true and fulldepth=false. The difference between 8 and 10 bits is just 2 bits, i.e., a maximum difference of 4. So if you just look at the frames, you may not see a gross difference, especially if there are no large flat areas where you would see banding. However, if you do a subtract between the two and then do levels in VirtualDub(2) and preview/sample frame, you can see the spike of differences that is 4 pixels wide. If you zoom in the two ends of the Input levels slider to just bracket the spike, then you can see the detail that is being retained in those lower two bits. Those 2 bits break what would have been a difference of 1 to a difference of 4, or to say it another way, the granularity is improved by a factor of 4, and that's why banding is significantly reduced.

gonca
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Re: HDR -> SDR tonemapping

Post by gonca » Wed Apr 18, 2018 5:21 pm

Okay.
I asked you before if fulldepth=True operated the same as fulldepth=false on 8 bits sources.
I believe you said yes, so I always include True.
10 bit sources get passed as 10 bit, 8 bit sources get passed as 8 bit
I realize that on some sources 8 or 10 bit makes little difference, but on some the extra 2 bits can make a lot of difference on detail and color retention.
One question though
The ConvertBits(10) call comes after DGSource(xxx, fulldepth=True)
Shouldn't the output of DGSource already be 10 bit?
I do realize that if the source is 8 bit running it in 10 bit can be beneficial, especially in terms of banding, but the source should already be 10 bit as this should be a hdr source.
I am not questioning you so much as I am asking for info/knowledge on the why
Either way thank you for your continuous efforts and improvements to your software :salute:

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admin
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Re: HDR -> SDR tonemapping

Post by admin » Wed Apr 18, 2018 5:42 pm

DGSource(fulldepth=true) outputs 16-bit always, with the extra bits zeroed, i.e., for 10-bit source, the lower 6 bits are zero. So the ConvertBits() call gets rid of the extra lower bits. I did a subtract+levels test between the frames with and without the ConvertBits() and was able to see some extra detail being retained with the ConvertBits().

I welcome being questioned because I am a seeker after truth and things should stand up to scrutiny and healthy skepticism.

Off to the pool!

gonca
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Re: HDR -> SDR tonemapping

Post by gonca » Wed Apr 18, 2018 5:59 pm

Quick 2 questions
On hdr to hdr cases would you recommend using ConvertBits(10) for 10 bit sources to 10 bit output

On sdr to sdr cases would you recommend using ConvertBits(8) or fulldepth=False (8bit source to 8 bit output) :?:

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admin
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Re: HDR -> SDR tonemapping

Post by admin » Wed Apr 18, 2018 8:34 pm

gonca wrote:
Wed Apr 18, 2018 5:59 pm
On hdr to hdr cases would you recommend using ConvertBits(10) for 10 bit sources to 10 bit output?
It depends on what your encoder wants to receive. Otherwise, it doesn't matter, unless you doing some gamma adjustment or something unusual like that. In that case, umm, it depends. :lol:
On sdr to sdr cases would you recommend using ConvertBits(8) or fulldepth=False (8bit source to 8 bit output)?
Neither one is necessary as 8-bit will always be delivered as 8-bit. Anyway, fulldepth=false by default.

gonca
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Re: HDR -> SDR tonemapping

Post by gonca » Thu Apr 19, 2018 4:34 am

Do you know how to use ConvertBits() in VS? Is it doable?
Would fmtconv work as well as ConvertBits()?
I guess I can always convert my scrips to avs+ again

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DJATOM
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Re: HDR -> SDR tonemapping

Post by DJATOM » Thu Apr 19, 2018 4:42 am

fmtc can do bits conversion. If you don't want to convert with fmtc, internal resizers can perform bits conversion as well:

Code: Select all

from vapoursynth import core, YUV420P16
...
clip = core.resize.Point(clip, format=YUV420P16)

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