Add subtitle export feature with correct time-scale handling

README.md

@@ -296,6 +296,7 @@ options:
             Hide one or more display elements from the list below:
 
             bloom     - bloom effect
+            captions  - caption text
             date      - current date
             dirnames  - names of directories
             files     - file icons
@@ -327,6 +328,10 @@ options:
     --caption-offset X
             Caption horizontal offset (0 to centre captions).
 
+    --caption-export FILE
+            Export captions to subtitle file (SRT or WebVTT format).
+            File format is determined by extension (.srt or .vtt/.webvtt).
+
     -o, --output-ppm-stream FILE
             Output a PPM image stream to a file ('-' for STDOUT).
 

data/gource.1

@@ -268,6 +268,7 @@ Disable keyboard and mouse input.
 Hide one or more display elements from the list below:
 
     bloom     \- bloom effect
+    captions  \- caption text
     date      \- current date
     dirnames  \- names of directories
     files     \- file icons
@@ -300,6 +301,10 @@ Caption duration.
 \fB\-\-caption-offset X
 Caption horizontal offset (0 to centre captions).
 .TP
+\fB\-\-caption-export FILE
+Export captions to subtitle file (SRT or WebVTT format).
+File format is determined by extension (.srt or .vtt/.webvtt).
+.TP
 \fB\-o, \-\-output\-ppm\-stream FILE\fR
 Output a PPM image stream to a file ('\-' for STDOUT).
 

src/gource.cpp

@@ -17,6 +17,10 @@
 
 #include "gource.h"
 #include "core/png_writer.h"
+#include <fstream>
+#include <iomanip>
+#include <algorithm>
+#include <map>
 
 bool  gGourceDrawBackground  = true;
 bool  gGourceQuadTreeDebug   = false;
@@ -28,6 +32,8 @@ Gource::Gource(FrameExporter* exporter) {
 
     this->logfile = gGourceSettings.path;
     commitlog = 0;
+    subtitle_export_stream = 0;
+    subtitle_export_index = 1;
 
     //disable OpenGL 2.0 functions if not supported
     if(!GLEW_VERSION_2_0) gGourceSettings.ffp = true;
@@ -155,6 +161,7 @@ Gource::Gource(FrameExporter* exporter) {
     //min physics rate 60fps (ie maximum allowed delta 1.0/60)
     max_tick_rate = 1.0 / 60.0;
     runtime = 0.0f;
+    video_time = 0.0f;
     frameskip = 0;
     framecount = 0;
 
@@ -216,6 +223,12 @@ void Gource::writeCustomLog(const std::string& logfile, const std::string& outpu
 Gource::~Gource() {
     reset();
 
+    if(subtitle_export_stream) {
+        subtitle_export_stream->close();
+        delete subtitle_export_stream;
+        subtitle_export_stream = 0;
+    }
+
     if(logmill!=0)   delete logmill;
     if(root!=0)      delete root;
 
@@ -256,7 +269,15 @@ void Gource::update(float t, float dt) {
     scaled_dt *= gGourceSettings.time_scale;
 
     //have to manage runtime internally as we're messing with dt
-    if(!paused) runtime += scaled_dt;
+    if(!paused) {
+        runtime += scaled_dt;
+        // Track unscaled video time for subtitle export
+        if(frameExporter != 0) {
+            video_time += max_tick_rate;  // Advances by 1/framerate per frame (1/25, 1/30, or 1/60)
+        } else {
+            video_time = runtime;  // When not exporting, use runtime
+        }
+    }
 
     if(gGourceSettings.stop_at_time > 0.0 && runtime >= gGourceSettings.stop_at_time) stop_position_reached = true;
 
@@ -955,6 +976,7 @@ void Gource::reset() {
     currtime=0;
     lasttime=0;
     subseconds=0.0;
+    video_time=0.0f;
     tag_seq = 1;
     commit_seq = 1;
 }
@@ -1128,6 +1150,76 @@ void Gource::loadCaptions() {
 
 }
 
+void Gource::exportCaptions() {
+    if(gGourceSettings.caption_export_file.empty()) return;
+
+    subtitle_export_stream = new std::ofstream(gGourceSettings.caption_export_file.c_str());
+    if(!subtitle_export_stream->is_open()) {
+        fprintf(stderr, "Failed to open caption export file: %s\n", gGourceSettings.caption_export_file.c_str());
+        delete subtitle_export_stream;
+        subtitle_export_stream = 0;
+        return;
+    }
+
+    // Determine format from file extension and write header if needed
+    std::string ext = gGourceSettings.caption_export_file.substr(gGourceSettings.caption_export_file.find_last_of(".") + 1);
+    std::transform(ext.begin(), ext.end(), ext.begin(), ::tolower);
+
+    if(ext == "vtt" || ext == "webvtt") {
+        *subtitle_export_stream << "WEBVTT\n\n";
+    }
+
+    fprintf(stderr, "Caption export file opened: %s (will record actual timings)\n", gGourceSettings.caption_export_file.c_str());
+}
+
+void Gource::writeSubtitleEntry(RCaption* caption, float start_time, float end_time) {
+    if(!subtitle_export_stream || !subtitle_export_stream->is_open()) return;
+
+    // Determine format from file extension
+    std::string ext = gGourceSettings.caption_export_file.substr(gGourceSettings.caption_export_file.find_last_of(".") + 1);
+    std::transform(ext.begin(), ext.end(), ext.begin(), ::tolower);
+    bool is_webvtt = (ext == "vtt" || ext == "webvtt");
+
+    // Format time for SRT/WebVTT
+    int start_hours = (int)(start_time / 3600);
+    int start_mins = (int)((start_time - start_hours * 3600) / 60);
+    int start_secs = (int)(start_time - start_hours * 3600 - start_mins * 60);
+    int start_ms = (int)((start_time - (int)start_time) * 1000);
+
+    int end_hours = (int)(end_time / 3600);
+    int end_mins = (int)((end_time - end_hours * 3600) / 60);
+    int end_secs = (int)(end_time - end_hours * 3600 - end_mins * 60);
+    int end_ms = (int)((end_time - (int)end_time) * 1000);
+
+    if(is_webvtt) {
+        // WebVTT format
+        *subtitle_export_stream << std::setfill('0') << std::setw(2) << start_hours << ":"
+            << std::setfill('0') << std::setw(2) << start_mins << ":"
+            << std::setfill('0') << std::setw(2) << start_secs << "."
+            << std::setfill('0') << std::setw(3) << start_ms
+            << " --> "
+            << std::setfill('0') << std::setw(2) << end_hours << ":"
+            << std::setfill('0') << std::setw(2) << end_mins << ":"
+            << std::setfill('0') << std::setw(2) << end_secs << "."
+            << std::setfill('0') << std::setw(3) << end_ms << "\n";
+    } else {
+        // SRT format
+        *subtitle_export_stream << subtitle_export_index++ << "\n";
+        *subtitle_export_stream << std::setfill('0') << std::setw(2) << start_hours << ":"
+            << std::setfill('0') << std::setw(2) << start_mins << ":"
+            << std::setfill('0') << std::setw(2) << start_secs << ","
+            << std::setfill('0') << std::setw(3) << start_ms
+            << " --> "
+            << std::setfill('0') << std::setw(2) << end_hours << ":"
+            << std::setfill('0') << std::setw(2) << end_mins << ":"
+            << std::setfill('0') << std::setw(2) << end_secs << ","
+            << std::setfill('0') << std::setw(3) << end_ms << "\n";
+    }
+
+    *subtitle_export_stream << caption->getCaption() << "\n\n";
+    subtitle_export_stream->flush();
+}
+
 void Gource::readLog() {
     if(stop_position_reached) return;
 
@@ -1717,6 +1809,7 @@ void Gource::logic(float t, float dt) {
         subseconds = 0.0;
 
         loadCaptions();
+        exportCaptions();
     }
 
     //set current time
@@ -1806,51 +1899,71 @@ void Gource::logic(float t, float dt) {
         reloaded = false;
     }
 
-    while(captions.size() > 0) {
-        RCaption* caption = captions.front();
+    // Process captions if we need to display them OR export them
+    bool process_captions = !gGourceSettings.hide_captions || (subtitle_export_stream && subtitle_export_stream->is_open());
+
+    if(process_captions) {
+        while(captions.size() > 0) {
+            RCaption* caption = captions.front();
 
-        if(caption->timestamp > currtime) break;
+            if(caption->timestamp > currtime) break;
 
-        float y = caption_start_y;
+            // Record when this caption becomes active for subtitle export
+            if(subtitle_export_stream && subtitle_export_stream->is_open()) {
+                caption_start_times[caption] = video_time;  // Use unscaled video time
+            }
 
-        while(1) {
+            // Only calculate position if we're showing captions
+            if(!gGourceSettings.hide_captions) {
+                float y = caption_start_y;
 
-            bool found = false;
+                while(1) {
+                    bool found = false;
 
-            for(RCaption* cap : active_captions) {
+                    for(RCaption* cap : active_captions) {
+                        if(cap->getPos().y == y) {
+                            found = true;
+                            break;
+                        }
+                    }
 
-                if(cap->getPos().y == y) {
-                    found = true;
-                    break;
+                    if(!found) break;
+                    y -= caption_height;
                 }
-            }
 
-            if(!found) break;
+                int caption_offset_x = gGourceSettings.caption_offset;
 
-            y -= caption_height;
-        }
+                // centre
+                if(caption_offset_x == 0) {
+                    caption_offset_x = (display.width / 2) - (fontcaption.getWidth(caption->getCaption()) / 2);
+                } else if(caption_offset_x < 0) {
+                    caption_offset_x = display.width + caption_offset_x - fontcaption.getWidth(caption->getCaption());
+                }
 
-        int caption_offset_x = gGourceSettings.caption_offset;
+                caption->setPos(vec2(caption_offset_x, y));
+            }
 
-        // centre
-        if(caption_offset_x == 0) {
-            caption_offset_x = (display.width / 2) - (fontcaption.getWidth(caption->getCaption()) / 2);
-        } else if(caption_offset_x < 0) {
-            caption_offset_x = display.width + caption_offset_x - fontcaption.getWidth(caption->getCaption());
+            captions.pop_front();
+            active_captions.push_back(caption);
         }
-
-        caption->setPos(vec2(caption_offset_x, y));
-
-        captions.pop_front();
-        active_captions.push_back(caption);
     }
 
+    // Process all active captions (visible or hidden)
     for(std::list<RCaption*>::iterator it = active_captions.begin(); it!=active_captions.end();) {
          RCaption* caption = *it;
 
          caption->logic(dt);
 
          if(caption->isFinished()) {
+             // Export subtitle when it finishes
+             if(subtitle_export_stream && subtitle_export_stream->is_open()) {
+                 auto start_it = caption_start_times.find(caption);
+                 if(start_it != caption_start_times.end()) {
+                     writeSubtitleEntry(caption, start_it->second, video_time);
+                     caption_start_times.erase(start_it);
+                 }
+             }
+
              it = active_captions.erase(it);
              delete caption;
              continue;
@@ -2655,10 +2768,12 @@ void Gource::draw(float t, float dt) {
         fontmedium.alignTop(true);
     }
 
-    for(std::list<RCaption*>::iterator it = active_captions.begin(); it!=active_captions.end(); it++) {
-        RCaption* caption = *it;
+    if(!gGourceSettings.hide_captions) {
+        for(std::list<RCaption*>::iterator it = active_captions.begin(); it!=active_captions.end(); it++) {
+            RCaption* caption = *it;
 
-        caption->draw();
+            caption->draw();
+        }
     }
 
     //file key

src/gource.h

@@ -145,6 +145,7 @@ class Gource : public SDLApp {
     time_t currtime;
     time_t lasttime;
     float runtime;
+    float video_time;  // Unscaled time for subtitle export
     float subseconds;
 
     float splash;
@@ -185,6 +186,11 @@ class Gource : public SDLApp {
 
     std::list<RCaption*> captions;
     std::list<RCaption*> active_captions;
+
+    // Subtitle export tracking
+    std::ofstream* subtitle_export_stream;
+    int subtitle_export_index;
+    std::map<RCaption*, float> caption_start_times;
 
     QuadTree* dirNodeTree;
     QuadTree* userTree;
@@ -208,6 +214,8 @@ class Gource : public SDLApp {
     void selectNextUser();
 
     void loadCaptions();
+    void exportCaptions();
+    void writeSubtitleEntry(RCaption* caption, float start_time, float end_time);
 
     void readLog();
 

src/gource_settings.cpp

@@ -180,6 +180,7 @@ if(extended_help) {
     printf("  --filename-time SECONDS  Duration to keep filenames on screen (default: 4.0)\n\n");
 
     printf("  --caption-file FILE         Caption file\n");
+    printf("  --caption-export FILE       Export captions to file (SRT or WebVTT format)\n");
     printf("  --caption-size SIZE         Caption font size\n");
     printf("  --caption-colour FFFFFF     Caption colour in hex\n");
     printf("  --caption-duration SECONDS  Caption duration (default: 10.0)\n");
@@ -271,6 +272,7 @@ GourceSettings::GourceSettings() {
     arg_types["hide-bloom"]              = "bool";
     arg_types["hide-mouse"]              = "bool";
     arg_types["hide-root"]               = "bool";
+    arg_types["hide-captions"]           = "bool";
     arg_types["highlight-users"]         = "bool";
     arg_types["highlight-dirs"]          = "bool";
     arg_types["file-extensions"]         = "bool";
@@ -354,6 +356,7 @@ GourceSettings::GourceSettings() {
     arg_types["dir-colour"]         = "string";
 
     arg_types["caption-file"]       = "string";
+    arg_types["caption-export"]     = "string";
     arg_types["caption-size"]       = "int";
     arg_types["caption-duration"]   = "float";
     arg_types["caption-colour"]     = "string";
@@ -383,6 +386,7 @@ void GourceSettings::setGourceDefaults() {
     hide_bloom     = false;
     hide_mouse     = false;
     hide_root      = false;
+    hide_captions  = false;
 
     start_timestamp = 0;
     start_date = "";
@@ -478,6 +482,7 @@ void GourceSettings::setGourceDefaults() {
     highlight_dirs = false;
 
     caption_file     = "";
+    caption_export_file = "";
     caption_duration = 10.0f;
     caption_size     = 16;
     caption_offset   = 0;
@@ -695,6 +700,7 @@ void GourceSettings::importGourceSettings(ConfFile& conffile, ConfSection* gourc
             else if(hidestr == "bloom")     hide_bloom     = true;
             else if(hidestr == "progress")  hide_progress  = true;
             else if(hidestr == "root")      hide_root      = true;
+            else if(hidestr == "captions")  hide_captions  = true;
             else if(hidestr == "mouse")     {
                 hide_mouse     = true;
                 hide_progress  = true;
@@ -874,6 +880,13 @@ void GourceSettings::importGourceSettings(ConfFile& conffile, ConfSection* gourc
         }
     }
 
+    if((entry = gource_settings->getEntry("caption-export")) != 0) {
+
+        if(!entry->hasValue()) conffile.entryException(entry, "specify caption export file (filename)");
+
+        caption_export_file = entry->getString();
+    }
+
     if((entry = gource_settings->getEntry("caption-duration")) != 0) {
 
         if(!entry->hasValue()) conffile.entryException(entry, "specify caption duration (seconds)");