Added VFR support. (Untested, as usual.)

Originally committed to SVN as r1477.

OverLua/avisynth.cpp

@@ -31,6 +31,7 @@
 #include "avisynth.h"
 
 #include "overlua.h"
+#include "vfr.h"
 
 // Lots of code lifted from the CSRI avisynth.cpp
 
@@ -38,6 +39,7 @@ class OverLuaAvisynth : public GenericVideoFilter {
 private:
 	OverLuaScript *script;
 	double spf; // seconds per frame - for frame/timestamp conversion
+	VFRTranslator *vfr;
 
 public:
 	OverLuaAvisynth(PClip _child, IScriptEnvironment *env, const char *file, const char *datastring, const char *vfrfile)
@@ -55,6 +57,10 @@ public:
 		try {
 			script = new OverLuaScript(file, datastring);
 			spf = (double)vi.fps_denominator / (double)vi.fps_numerator;
+			if (vfrfile)
+				vfr = GetVFRTranslator(vfrfile);
+			else
+				vfr = 0;
 		}
 		catch (const char *e) {
 			env->ThrowError(e);
@@ -66,6 +72,8 @@ public:
 
 	~OverLuaAvisynth()
 	{
+		if (vfr)
+			delete vfr;
 		delete script;
 	}
 
@@ -76,6 +84,8 @@ public:
 		env->MakeWritable(&avsframe);
 
 		double frametime = n * spf;
+		if (vfr)
+			frametime = vfr->TimeStampFromFrameNumber(n);
 		ptrdiff_t stride = avsframe->GetPitch();
 		unsigned char *plane = avsframe->GetWritePtr();
 

OverLua/docs/overlua.txt

@@ -20,7 +20,6 @@ subtitles/karaoke.
 vfrfile is the path to a timecode file Matroska format 1 or 2. If supplied,
 it will be used to translate frame numbers to timestamps instead of relying
 on the frame rate provided by Avisynth.
-VFR support is not implemented yet.
 
 
 API the Lua script must implement

OverLua/vfr.cpp

@@ -0,0 +1,184 @@
+/*
+ * VFR translation functions for OverLua
+ *
+
+    Copyright 2007  Niels Martin Hansen
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    Contact:
+    E-mail: <jiifurusu@gmail.com>
+    IRC: jfs in #aegisub on irc.rizon.net
+
+ */
+
+#include "vfr.h"
+#include <stdio.h>
+#include <string.h>
+#include <vector>
+
+
+// Work with seconds per frame (spf) here instead of fps since that's more natural for the translation we're doing
+
+
+class TimecodesV1 : public VFRTranslator {
+private:
+	// Used when sections run out
+	double default_spf;
+	double first_non_section_timestamp;
+	int first_non_section_frame;
+
+	// Also generate sections for unspecified ones
+	// (use the default framerate then)
+	struct FrameRateSection {
+		double start_time;
+		double spf;
+		int start_frame;
+		int end_frame;
+	};
+	std::vector<FrameRateSection> sections;
+
+public:
+	virtual double TimeStampFromFrameNumber(int n)
+	{
+		// Find correct section
+		for (size_t i = 0; i < sections.size(); i++) {
+			FrameRateSection &sect = sections[i];
+			if (n >= sect.start_frame && n <= sect.end_frame) {
+				return sect.start_time + (n - sect.start_frame) * sect.spf;
+			}
+		}
+		// Not in a section
+		if (n < 0) return 0.0;
+		return first_non_section_timestamp + (n - first_non_section_frame) * default_spf;
+	}
+
+	TimecodesV1(FILE *vfrfile)
+	{
+		char buf[100];
+
+		default_spf = -1;
+		double cur_time = 0.0;
+
+		FrameRateSection temp_section;
+		temp_section.start_time = 0.0;
+		temp_section.spf = -1;
+		temp_section.start_frame = 0;
+		temp_section.end_frame = 0;
+
+		while (fgets(buf, 100, vfrfile)) {
+			// Comment?
+			if (buf[0] == '#') continue;
+
+			if (strncmp(buf, "Assume ", 7) == 0 && default_spf < 0) {
+				char *num = buf+7;
+				default_spf = atof(num);
+				if (default_spf > 0)
+					default_spf = 1 / default_spf;
+				else
+					default_spf = -1;
+				temp_section.spf = default_spf;
+				continue;
+			}
+
+			int start_frame, end_frame;
+			double fps;
+			if (scanf("%d,%d,%f", &start_frame, &end_frame, &fps) == 3) {
+				// Finish the current temp section
+				temp_section.end_frame = start_frame - 1;
+				if (temp_section.end_frame >= temp_section.start_frame) {
+					cur_time += (temp_section.end_frame - temp_section.start_frame + 1) * temp_section.spf;
+					sections.push_back(temp_section);
+				}
+				// Insert the section corresponding to this line
+				temp_section.spf = 1/fps;
+				temp_section.start_frame = start_frame;
+				temp_section.end_frame = end_frame;
+				temp_section.start_time = cur_time;
+				cur_time += (end_frame - start_frame + 1) / fps;
+				sections.push_back(temp_section);
+				// Begin new temp section
+				temp_section.spf = default_spf;
+				temp_section.start_frame = end_frame + 1;
+				temp_section.end_frame = end_frame; // yes, negative duration
+				temp_section.start_time = cur_time;
+			}
+		}
+
+		first_non_section_timestamp = cur_time;
+		first_non_section_frame = temp_section.start_frame;
+	}
+
+};
+
+
+class TimecodesV2 : public VFRTranslator {
+private:
+	// Main data
+	std::vector<double> timestamps;
+	// For when data are exhausted (well, they shouldn't, then the vfr file is bad)
+	int last_known_frame;
+	double last_known_timestamp;
+	double assumed_spf;
+
+public:
+	virtual double TimeStampFromFrameNumber(int n)
+	{
+		if (n < (int)timestamps.size() && n >= 0) {
+			return timestamps[n];
+		}
+		if (n < 0) return 0.0;
+		return last_known_timestamp + (n - last_known_frame) * assumed_spf;
+	}
+
+	TimecodesV2(FILE *vfrfile)
+	{
+		char buf[50];
+
+		timestamps.reserve(8192); // should be enough for most cases
+
+		while (fgets(buf, 50, vfrfile)) {
+			// Comment?
+			if (buf[0] == '#') continue;
+			// Otherwise assume it's a good timestamp
+			timestamps.push_back(atof(buf));
+		}
+
+		last_known_frame = (int)timestamps.size()-1;
+		last_known_timestamp = timestamps[last_known_frame];
+		assumed_spf = 1/25.0; // yes, this is stupid - anyone got a better idea?
+	}
+
+};
+
+
+VFRTranslator *GetVFRTranslator(const char *vfrfile)
+{
+	char buf[32];
+	buf[19] = 0; // In "# timecode format v1" the version number is character index 19
+	FILE *f = fopen(vfrfile, "r");
+	VFRTranslator *res = 0;
+	if (fgets(buf, 32, f) && buf[0] == '#') {
+		// So do some really shoddy parsing here, assume the file is good
+		if (buf[19] == '1') {
+			res = new TimecodesV1(f);
+		} else if (buf[19] == '2') {
+			res = new TimecodesV2(f);
+		}
+	}
+	fclose(f);
+	return res;
+}
+

OverLua/vfr.h

@@ -0,0 +1,37 @@
+/*
+ * VFR translation functions for OverLua
+ *
+
+    Copyright 2007  Niels Martin Hansen
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    Contact:
+    E-mail: <jiifurusu@gmail.com>
+    IRC: jfs in #aegisub on irc.rizon.net
+
+ */
+
+#ifndef VFR_H
+#define VFR_H
+
+class VFRTranslator {
+public:
+	virtual double TimeStampFromFrameNumber(int n) = 0;
+};
+
+VFRTranslator *GetVFRTranslator(const char *vfrfile);
+
+#endif