find starting number for image sequences automatically

io/loadthread.cpp

@@ -290,6 +290,8 @@ bool LoadThread::load_worker(QFile& f, QXmlStreamReader& stream, int type) {
                   f->proxy = (attr.value() == "1");
                 } else if (attr.name() == "proxypath") {
                   f->proxy_path = attr.value().toString();
+                } else if (attr.name() == "startnumber") {
+                  f->start_number = attr.value().toInt();
                 }
               }
 

io/previewgenerator.cpp

@@ -524,7 +524,15 @@ void PreviewGenerator::run() {
 
   QString errorStr;
   bool error = false;
-  int errCode = avformat_open_input(&fmt_ctx_, filename, nullptr, nullptr);
+
+  AVDictionary* format_opts = nullptr;
+
+  // for image sequences that don't start at 0, set the index where it does start
+  if (footage_->start_number > 0) {
+    av_dict_set(&format_opts, "start_number", QString::number(footage_->start_number).toUtf8(), 0);
+  }
+
+  int errCode = avformat_open_input(&fmt_ctx_, filename, nullptr, &format_opts);
   if(errCode != 0) {
     char err[1024];
     av_strerror(errCode, err, 1024);

io/proxygenerator.cpp

@@ -47,9 +47,15 @@ void ProxyGenerator::transcode(const ProxyInfo& info) {
   // set progress to 0
   current_progress = 0.0;
 
+  // for image sequences that don't start at 0, set the index where it does start
+  AVDictionary* format_opts = nullptr;
+  if (footage->start_number > 0) {
+    av_dict_set(&format_opts, "start_number", QString::number(footage->start_number).toUtf8(), 0);
+  }
+
   // open input file
   AVFormatContext* input_fmt_ctx = nullptr;
-  avformat_open_input(&input_fmt_ctx, footage->url.toUtf8(), nullptr, nullptr);
+  avformat_open_input(&input_fmt_ctx, footage->url.toUtf8(), nullptr, &format_opts);
 
   // open output file
   AVFormatContext* output_fmt_ctx = nullptr;

panels/project.cpp

@@ -740,7 +740,11 @@ void Project::process_file_list(QStringList& files, bool recursive, Media* repla
 
       if (lastcharindex == 0) lastcharindex++;
 
+      // used for image sequences that don't start at "0"
+      int start_number = 0;
+
       if (found && file[lastcharindex-1].isDigit()) {
+
         bool is_img_sequence = false;
 
         // how many digits are in the filename?
@@ -787,6 +791,17 @@ void Project::process_file_list(QStringList& files, bool recursive, Media* repla
                                       QMessageBox::Yes) == QMessageBox::Yes) {
               file = new_filename;
               image_sequence_importassequence.append(true);
+
+
+              // try to find the start number for this image sequence
+              int test_file_number = file_number;
+              do {
+                test_file_number--;
+              } while (QFileInfo::exists(QString("%1%2%3").arg(file.left(digit_test),
+                                                               QString("%1").arg(test_file_number, digit_count, 10, QChar('0')),
+                                                               file.mid(lastcharindex))));
+              start_number = test_file_number + 1;
+
             } else {
               image_sequence_importassequence.append(false);
             }
@@ -809,6 +824,7 @@ void Project::process_file_list(QStringList& files, bool recursive, Media* repla
         m->using_inout = false;
         m->url = file;
         m->name = get_file_name_from_path(files.at(i));
+        m->start_number = start_number;
 
         item->set_footage(m);
 
@@ -1028,6 +1044,7 @@ void Project::save_folder(QXmlStreamWriter& stream, int type, bool set_ids_only,
           stream.writeAttribute("out", QString::number(f->out));
           stream.writeAttribute("speed", QString::number(f->speed));
           stream.writeAttribute("alphapremul", QString::number(f->alpha_is_premultiplied));
+          stream.writeAttribute("startnumber", QString::number(f->start_number));
 
           stream.writeAttribute("proxy", QString::number(f->proxy));
           stream.writeAttribute("proxypath", f->proxy_path);

project/footage.cpp

@@ -27,16 +27,17 @@
 
 #include "project/clip.h"
 
-Footage::Footage() :
-	ready(false),
-	preview_gen(nullptr),
-	invalid(false),
-	in(0),
-	out(0),
-	speed(1.0),
-	alpha_is_premultiplied(false),
-	proxy(false)
-{
+Footage::Footage() {
+  ready = (false);
+  preview_gen = (nullptr);
+  invalid = (false);
+  in = (0);
+  out = (0);
+  speed = (1.0);
+  alpha_is_premultiplied = (false);
+  proxy = (false);
+  start_number = 0;
+
 	ready_lock.lock();
 }
 

project/footage.h

@@ -82,6 +82,7 @@ struct Footage {
   bool invalid;
   double speed;
   bool alpha_is_premultiplied;
+  int start_number;
 
   // proxy config
   bool proxy;

rendering/cacher.cpp

@@ -781,12 +781,18 @@ void Cacher::OpenWorker() {
     const char* filename = ba.constData();
     const FootageStream* ms = clip->media_stream();
 
+    // for image sequences that don't start at 0, set the index where it does start
+    AVDictionary* format_opts = nullptr;
+    if (m->start_number > 0) {
+      av_dict_set(&format_opts, "start_number", QString::number(m->start_number).toUtf8(), 0);
+    }
+
     formatCtx = nullptr;
     int errCode = avformat_open_input(
           &formatCtx,
           filename,
           nullptr,
-          nullptr
+          &format_opts
           );
     if (errCode != 0) {
       char err[1024];