Use libx264 or libopenh264 for mp4 renders if ffmpeg supported

toonz/sources/image/ffmpeg/tiio_ffmpeg.cpp

@@ -124,6 +124,28 @@ bool Ffmpeg::checkFormat(std::string format) {
   return false;
 }
 
+bool Ffmpeg::checkCodecs(std::string codec) {
+  QString path = Preferences::instance()->getFfmpegPath() + "/ffmpeg";
+#if defined(_WIN32)
+  path = path + ".exe";
+#endif
+  QStringList args;
+  args << "-codecs";
+  QProcess ffmpeg;
+  ffmpeg.start(path, args);
+  if (waitFfmpeg(ffmpeg, 60000)) { // 1 minute timeout
+    QString results = ffmpeg.readAllStandardError();
+    results += ffmpeg.readAllStandardOutput();
+    ffmpeg.close();
+    std::string strResults = results.toStdString();
+    std::string::size_type n;
+    n = strResults.find(codec);
+    if (n != std::string::npos)
+      return true;
+  }
+  return false;
+}
+
 TFilePath Ffmpeg::getFfmpegCache() {
   QString cacheRoot = ToonzFolder::getCacheRootFolder().getQString();
   if (!TSystem::doesExistFileOrLevel(TFilePath(cacheRoot + "/ffmpeg"))) {

toonz/sources/image/ffmpeg/tiio_ffmpeg.h

@@ -34,6 +34,7 @@ public:
   static bool checkFfmpeg();
   static bool checkFfprobe();
   static bool checkFormat(std::string format);
+  static bool checkCodecs(std::string format);
   double getFrameRate();
   TDimension getSize();
   int getFrameCount();

toonz/sources/image/ffmpeg/tiio_mp4.cpp

@@ -90,6 +90,13 @@ TLevelWriterMp4::~TLevelWriterMp4() {
   postIArgs << QString::number(outLx) + "x" + QString::number(outLy);
   postIArgs << "-b";
   postIArgs << QString::number(finalBitrate) + "k";
+  if (Ffmpeg::checkCodecs("libopenh264")) {
+    postIArgs << "-c:v";
+    postIArgs << "libopenh264";
+  } else if (Ffmpeg::checkCodecs("libxh264")) {
+    postIArgs << "-c:v";
+    postIArgs << "libxh264";
+  }
 
   ffmpegWriter->runFfmpeg(preIArgs, postIArgs, false, false, true);
   ffmpegWriter->cleanUpFiles();