Write dive data as video subtitles

This commit adds an entry to the dive media context
menu which offers to write a subtitle file. This
creates an .ass file for the selected videos.

In an attempt to to clutter the screen too much, don't
show irrelevant entries (zero temperature or
NDL and show TTS only for dives with stops).

VLC is able to show these subtitles directly, they
can be integrated into the video file with ffmpeg.

Signed-off-by: Robert C. Helling <helling@atdotde.de>

2 files changed, 65 insertions, 0 deletions

diff --git a/core/save-profiledata.c b/core/save-profiledata.c
index 603045fe0..09ac76886 100644
--- a/core/save-profiledata.c
+++ b/core/save-profiledata.c
@@ -5,6 +5,7 @@
 #include "core/membuffer.h"
 #include "core/subsurface-string.h"
 #include "core/save-profiledata.h"
+#include "core/version.h"
 
 static void put_int(struct membuffer *b, int val)
 {
@@ -21,6 +22,15 @@ static void put_double(struct membuffer *b, double val)
 	put_format(b, "\"%f\" ", val);
 }
 
+static void put_video_time(struct membuffer *b, int secs)
+{
+	int hours = secs / 3600;
+	secs -= hours * 3600;
+	int mins = secs / 60;
+	secs -= mins * 60;
+	put_format(b, "%d:%02d:%02d.000,", hours, mins, secs);
+}
+
 static void put_pd(struct membuffer *b, struct plot_data *entry)
 {
 	if (!entry)
@@ -148,6 +158,39 @@ static void put_headers(struct membuffer *b)
 	put_csv_string(b, "icd_warning");
 }
 
+static void put_st_event(struct membuffer *b, struct plot_data *entry, int offset, int length)
+{
+	double value;
+	int decimals;
+	const char *unit;
+
+	if (entry->sec < offset || entry->sec > offset + length)
+		return;
+
+	put_format(b, "Dialogue: 0,");
+	put_video_time(b, entry->sec - offset);
+	put_video_time(b, (entry+1)->sec - offset < length ? (entry+1)->sec - offset : length);
+	put_format(b, "Default,,0,0,0,,");
+	put_format(b, "%d:%02d ", FRACTION(entry->sec, 60));
+	value = get_depth_units(entry->depth, &decimals, &unit);
+	put_format(b, "D=%02.2f %s ", value, unit);
+	if (entry->temperature) {
+		value = get_temp_units(entry->temperature, &unit);
+		put_format(b, "T=%.1f%s ", value, unit);
+	}
+	// Only show NDL if it is not essentially infinite, show TTS for mandatory stops.
+	if (entry->ndl_calc < 3600) {
+		if (entry->ndl_calc > 0)
+			put_format(b, "NDL=%d:%02d ", FRACTION(entry->ndl_calc, 60));
+		else
+			if (entry->tts_calc > 0)
+				put_format(b, "TTS=%d:%02d ", FRACTION(entry->tts_calc, 60));
+	}
+	if (entry->surface_gf > 0.0) {
+		put_format(b, "sGF=%.1f%% ", entry->surface_gf);
+	}
+	put_format(b, "\n");
+}
 static void save_profiles_buffer(struct membuffer *b, bool select_only)
 {
 	int i;
@@ -171,6 +214,27 @@ static void save_profiles_buffer(struct membuffer *b, bool select_only)
 	}
 }
 
+void save_subtitles_buffer(struct membuffer *b, struct dive *dive, int offset, int length)
+{
+	struct plot_info pi;
+	struct deco_state *planner_deco_state = NULL;
+
+	pi = calculate_max_limits_new(dive, &dive->dc);
+	create_plot_info_new(dive, &dive->dc, &pi, false, planner_deco_state);
+
+	put_format(b, "[Script Info]\n");
+	put_format(b, "; Script generated by Subsurface %s\n", subsurface_canonical_version());
+	put_format(b, "ScriptType: v4.00+\nPlayResX: 384\nPlayResY: 288\n\n");
+	put_format(b, "[V4+ Styles]\nFormat: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding\n");
+	put_format(b, "Style: Default,Arial,12,&Hffffff,&Hffffff,&H0,&H0,0,0,0,0,100,100,0,0,1,1,0,7,10,10,10,0\n\n");
+	put_format(b, "[Events]\nFormat: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\n");
+
+	for (int i = 0; i < pi.nr; i++) {
+		put_st_event(b, &pi.entry[i], offset, length);
+	}
+	put_format(b, "\n");
+}
+
 int save_profiledata(const char *filename, const bool select_only)
 {
 	struct membuffer buf = { 0 };
diff --git a/core/save-profiledata.h b/core/save-profiledata.h
index 23e833a27..fd38e48ca 100644
--- a/core/save-profiledata.h
+++ b/core/save-profiledata.h
@@ -9,6 +9,7 @@ extern "C" {
 #endif
 
 int save_profiledata(const char *filename, bool selected_only);
+void save_subtitles_buffer(struct membuffer *b, struct dive *dive, int offset, int length);
 
 #ifdef __cplusplus
 }