From e11e0f20770284cb9205903dffd3a58b3d75981e Mon Sep 17 00:00:00 2001
From: Rodney <rodney.baker@gmail.com>
Date: Jul 27 2022 18:06:22 +0000
Subject: Merge pull request #4486 from justburner/FixMTStartFrameFFMPEG


Fix Starting frame Multi-thread FFMPEG
---

diff --git a/toonz/sources/image/ffmpeg/tiio_ffmpeg.cpp b/toonz/sources/image/ffmpeg/tiio_ffmpeg.cpp
index e70d0f3..9a58f3f 100644
--- a/toonz/sources/image/ffmpeg/tiio_ffmpeg.cpp
+++ b/toonz/sources/image/ffmpeg/tiio_ffmpeg.cpp
@@ -18,22 +18,24 @@ Ffmpeg::Ffmpeg() {
   m_ffmpegTimeout      = Preferences::instance()->getFfmpegTimeout() * 1000;
   std::string strPath  = m_ffmpegPath.toStdString();
   m_intermediateFormat = "png";
+  m_startNumber        = 2147483647;  // Lowest frame determines starting frame
 }
 Ffmpeg::~Ffmpeg() {}
 
 bool Ffmpeg::checkFfmpeg() {
-  // check the user defined path in preferences first
-  QString path = Preferences::instance()->getFfmpegPath() + "/ffmpeg";
+  // ffmpeg executable
 #if defined(_WIN32)
-  path = path + ".exe";
+  QString exe = "/ffmpeg.exe";
+#else
+  QString exe = "/ffmpeg";
 #endif
+
+  // check the user defined path in preferences first
+  QString path = Preferences::instance()->getFfmpegPath() + exe;
   if (TSystem::doesExistFileOrLevel(TFilePath(path))) return true;
 
   // check the OpenToonz root directory next
-  path = QDir::currentPath() + "/ffmpeg";
-#if defined(_WIN32)
-  path = path + ".exe";
-#endif
+  path = QDir::currentPath() + exe;
   if (TSystem::doesExistFileOrLevel(TFilePath(path))) {
     Preferences::instance()->setValue(ffmpegPath, QDir::currentPath());
     return true;
@@ -103,10 +105,11 @@ void Ffmpeg::setPath(TFilePath path) { m_path = path; }
 
 void Ffmpeg::createIntermediateImage(const TImageP &img, int frameIndex) {
   m_frameCount++;
-  if (m_frameNumberOffset == -1) m_frameNumberOffset = frameIndex - 1;
+  frameIndex--;  // ffmpeg start at 0 by default
+  if (frameIndex < m_startNumber) m_startNumber = frameIndex;
   QString tempPath = getFfmpegCache().getQString() + "//" +
                      QString::fromStdString(m_path.getName()) + "tempOut" +
-                     QString::number(frameIndex - m_frameNumberOffset) + "." +
+                     QString::number(frameIndex) + "." +
                      m_intermediateFormat;
   std::string saveStatus = "";
   TRasterImageP tempImage(img);
@@ -151,6 +154,10 @@ void Ffmpeg::runFfmpeg(QStringList preIArgs, QStringList postIArgs,
   args = args + preIArgs;
   if (!includesInPath) {  // NOTE:  if including the in path, it needs to be in
                           // the preIArgs argument.
+    if (m_startNumber != 0) {
+      args << "-start_number";
+      args << QString::number(m_startNumber);
+    }
     args << "-i";
     args << tempName;
   }
@@ -277,10 +284,13 @@ ffmpegFileInfo Ffmpeg::getInfo() {
     QByteArray ba = infoText.readAll();
     infoText.close();
     QString text = QString::fromStdString(ba.toStdString());
-    m_lx         = text.split(" ")[0].toInt();
-    m_ly         = text.split(" ")[1].toInt();
-    m_frameRate  = text.split(" ")[2].toDouble();
-    m_frameCount = text.split(" ")[3].toInt();
+    QStringList textlist = text.split(" ");
+    if (textlist.count() >= 4) {
+      m_lx         = textlist[0].toInt();
+      m_ly         = textlist[1].toInt();
+      m_frameRate  = textlist[2].toDouble();
+      m_frameCount = textlist[3].toInt();
+    }
   } else {
     QFile infoText(tempPath);
     getSize();
@@ -463,6 +473,11 @@ void Ffmpeg::getFramesFromMovie(int frame) {
     // frameArgs << "-accurate_seek";
     // frameArgs << "-ss";
     // frameArgs << "0" + QString::number(frameIndex / m_info->m_frameRate);
+    if (m_path.getType() == "webm") {
+      // To load in webm transparency
+      preIFrameArgs << "-vcodec";
+      preIFrameArgs << "libvpx";
+    }
     preIFrameArgs << "-i";
     preIFrameArgs << m_path.getQString();
     postIFrameArgs << "-y";
diff --git a/toonz/sources/image/ffmpeg/tiio_ffmpeg.h b/toonz/sources/image/ffmpeg/tiio_ffmpeg.h
index 6ec415a..359b84b 100644
--- a/toonz/sources/image/ffmpeg/tiio_ffmpeg.h
+++ b/toonz/sources/image/ffmpeg/tiio_ffmpeg.h
@@ -47,7 +47,7 @@ public:
 private:
   QString m_intermediateFormat, m_ffmpegPath, m_audioPath, m_audioFormat;
   int m_frameCount    = 0, m_lx, m_ly, m_bpp, m_bitsPerSample, m_channelCount,
-      m_ffmpegTimeout = 30000, m_frameNumberOffset = -1;
+      m_ffmpegTimeout = 30000, m_startNumber = 2147483647;
   double m_frameRate  = 24.0;
   bool m_ffmpegExists = false, m_ffprobeExists = false, m_hasSoundTrack = false;
   TFilePath m_path;