Filter SDK/CInvertNeg - Revision history

Admin at 22:43, 13 January 2017

2017-01-13T22:43:53Z

← Older revision		Revision as of 00:43, 14 January 2017
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	return v;		return v;

	Finally we return. ~~"v" is either~~ an error ~~or the new clip~~.		Finally we return our new clip. We could also have returned an error instead (instead of returning an error right away).

	const char* AVSC_CC avisynth_c_plugin_init(AVS_ScriptEnvironment * env)		const char* AVSC_CC avisynth_c_plugin_init(AVS_ScriptEnvironment * env)

Admin: /* Line by line breakdown */

2017-01-13T22:30:28Z

Line by line breakdown

← Older revision		Revision as of 00:30, 14 January 2017
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	This header declares all the classes and miscellaneous constants that you might need when writing a plugin. All external plugins should #include it.		This header declares all the classes and miscellaneous constants that you might need when writing a plugin. All external plugins should #include it.

	External plugins do not link with avisynth.dll, so they can't directly access functions that are defined in the main Avisynth source code. Therefore, every important function in avisynth_c.h is either defined inline or ~~declared as virtual~~ (???)~~. The virtual functions act as callbacks for external DLLs~~.		External plugins do not link with avisynth.dll, so they can't directly access functions that are defined in the main Avisynth source code. Therefore, every important function in avisynth_c.h is either defined inline or (???).

	AVS_VideoFrame* AVSC_CC InvertNeg_get_frame(AVS_FilterInfo* fi, int n)		AVS_VideoFrame* AVSC_CC InvertNeg_get_frame(AVS_FilterInfo* fi, int n)

Admin at 22:28, 13 January 2017

2017-01-13T22:28:07Z

← Older revision		Revision as of 00:28, 14 January 2017
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	if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {		if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {
	~~v =~~ avs_new_value_error("InvertNeg: planar YUV data only!");		return avs_new_value_error("InvertNeg: planar YUV data only!");
	~~} else {~~
	~~fi->get_frame = InvertNeg_get_frame;~~
	~~v = avs_new_value_clip(new_clip~~);
	}		}

			fi->get_frame = InvertNeg_get_frame;

			v = avs_new_value_clip(new_clip);

	avs_release_clip(new_clip);		avs_release_clip(new_clip);
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	if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {		if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {
	~~v =~~ avs_new_value_error("InvertNeg: planar YUV data only!");		return avs_new_value_error("InvertNeg: planar YUV data only!");
	} ~~else {~~		}

	Our filter will not work unless the video is stored as YUV planar. If this is not the case than an error is returned~~. This is done be setting the return value to an error condition~~.		Our filter will not work unless the video is stored as YUV planar. If this is not the case than an error is returned.

	fi->get_frame = InvertNeg_get_frame;		fi->get_frame = InvertNeg_get_frame;

	Here we are setting the get_frame callback. There are other callbacks but since "store_child" was set we do not have to worry about implementing all of them.		Here we are setting the get_frame callback. There are other callbacks (like get_audio, set_cache_hints and get_parity), but since "store_child" was set to true we do not have to worry about implementing all of them. Just the ones we need.

	v = avs_new_value_clip(new_clip);		v = avs_new_value_clip(new_clip);

	The return value is then set to the new clip returned by avs_new_c_filter. avs_new_value_clip ~~converts~~ the clip ~~info~~ an AVS_Value ~~(???)~~. It also creates a new reference to the clip.		The return value is then set to the new clip returned by avs_new_c_filter. avs_new_value_clip stores the clip in an AVS_Value which will be returned by our Create_InvertNeg. It also creates a new reference to the clip.

	avs_release_clip(new_clip);		avs_release_clip(new_clip);

Admin at 22:31, 12 January 2017

2017-01-12T22:31:26Z

← Older revision		Revision as of 00:31, 13 January 2017
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	avs_release_clip(new_clip);		avs_release_clip(new_clip);

	We must now release the clip returned by avs_new_c_filter. In the case of an error the clip is no longer needed. Otherwise a new reference is created to the clip with avs_new_value_clip so we must release the ~~orignal~~ reference.		We must now release the clip returned by avs_new_c_filter. In the case of an error the clip is no longer needed. Otherwise a new reference is created to the clip with avs_new_value_clip so we must release the original reference.

	return v;		return v;

Admin at 21:48, 12 January 2017

2017-01-12T21:48:35Z

← Older revision		Revision as of 23:48, 12 January 2017
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	[http://www.kevina.org/avisynth_c/example.html Kevin's AviSynth C API Docs] is the documentation written for the deprecated avisynth_c.dll by Kevin Atkinson, in its original form.		[http://www.kevina.org/avisynth_c/example.html Kevin's AviSynth C API Docs] is the documentation written for the deprecated avisynth_c.dll by Kevin Atkinson, in its original form.

	~~[[Category:FilterSDK]]~~
	[[Category:C API]]		[[Category:C API]]

Admin at 21:48, 12 January 2017

2017-01-12T21:48:01Z

← Older revision		Revision as of 23:48, 12 January 2017
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	[http://www.kevina.org/avisynth_c/example.html Kevin's AviSynth C API Docs] is the documentation written for the deprecated avisynth_c.dll by Kevin Atkinson, in its original form.		[http://www.kevina.org/avisynth_c/example.html Kevin's AviSynth C API Docs] is the documentation written for the deprecated avisynth_c.dll by Kevin Atkinson, in its original form.

			[[Category:FilterSDK]]
			[[Category:C API]]

Admin at 18:55, 29 December 2016

2016-12-29T18:55:10Z

← Older revision		Revision as of 20:55, 29 December 2016
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	AVS_Clip* new_clip = avs_new_c_filter(env, &fi, avs_array_elt(args, 0), 1);		AVS_Clip* new_clip = avs_new_c_filter(env, &fi, avs_array_elt(args, 0), 1);

	"avs_new_c_filter" creates a new filter. AVS_Clip is an abstract type representing a filter. In this case it will represent our new filter. "env" is the current script environment. "fi" will be set to point to our filter AVS_FilterInfo which is the concrete representation of a C filter. We will modify this structure later. "avs_array_elt(args, 0)" is accessing the first value of args, which is generally the parent clip. The last ~~paramater~~, is a boolean value "store_child". It should generally always be set to true.		"avs_new_c_filter" creates a new filter. AVS_Clip is an abstract type representing a filter. In this case it will represent our new filter. "env" is the current script environment. "fi" will be set to point to our filter AVS_FilterInfo which is the concrete representation of a C filter. We will modify this structure later. "avs_array_elt(args, 0)" is accessing the first value of args, which is generally the parent clip. The last parameter, is a boolean value "store_child". It should generally always be set to true.

	if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {		if (!avs_is_planar(&fi->vi) \|\| !avs_is_yuv(&fi->vi)) {

Admin at 18:51, 29 December 2016

2016-12-29T18:51:14Z

← Older revision		Revision as of 20:51, 29 December 2016
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	avs_release_clip(new_clip);		avs_release_clip(new_clip);

	We must now release the clip returned by ~~new_c_filter~~. In the case of an error the clip is no longer needed. Otherwise a new reference is created to the clip with ~~new_value_clip~~ so we must release the orignal reference.		We must now release the clip returned by avs_new_c_filter. In the case of an error the clip is no longer needed. Otherwise a new reference is created to the clip with avs_new_value_clip so we must release the orignal reference.

	return v;		return v;

Admin at 18:40, 29 December 2016

2016-12-29T18:40:17Z

← Older revision		Revision as of 20:40, 29 December 2016
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	return dst;		return dst;

	~~Finally we return~~ the ~~dest video~~ frame.		GetFrame returns the newly-created frame.

	AVS_Value AVSC_CC Create_InvertNeg(AVS_ScriptEnvironment* env, AVS_Value args, void* user_data)		AVS_Value AVSC_CC Create_InvertNeg(AVS_ScriptEnvironment* env, AVS_Value args, void* user_data)

Admin at 21:57, 28 December 2016

2016-12-28T21:57:39Z

← Older revision		Revision as of 23:57, 28 December 2016
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	}		}

	Compile this file into a DLL named InvertNeg.dll. See [[Filter_SDK/Compiling_instructions\|compiling instructions]]. Now create an Avisynth script which looks something like this:		Link to avisynth.lib and when using the MSVC++ compiler add the definition file. Compile this file into a DLL named InvertNeg.dll. See [[Filter_SDK/Compiling_instructions\|compiling instructions]]. Now create an Avisynth script which looks something like this:

	LoadCPlugin("d:\path\InvertNeg.dll")		LoadCPlugin("d:\path\InvertNeg.dll")