+ mux_data->track = MP4AddSubtitleTrack( m->file, 1 );
+
+ /* Tune track chunk duration */
+ MP4TuneTrackDurationPerChunk( m, mux_data->track );
+
+ const uint8_t textColor[4] = { 255,255,255,255 };
+ uint64_t subHeight = 60;
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "tkhd.alternate_group", 2);
+
+ MP4SetTrackFloatProperty(m->file, mux_data->track, "tkhd.width", job->width);
+ MP4SetTrackFloatProperty(m->file, mux_data->track, "tkhd.height", subHeight);
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.dataReferenceIndex", 1);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.horizontalJustification", 1);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.verticalJustification", 0);
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.bgColorAlpha", 255);
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.defTextBoxBottom", subHeight);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.defTextBoxRight", job->width);
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontID", 1);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontSize", 24);
+
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontColorRed", textColor[0]);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontColorGreen", textColor[1]);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontColorBlue", textColor[2]);
+ MP4SetTrackIntegerProperty(m->file, mux_data->track, "mdia.minf.stbl.stsd.tx3g.fontColorAlpha", textColor[3]);
+
+ /* translate the track */
+ uint8_t* val;
+ uint8_t nval[36];
+ uint32_t *ptr32 = (uint32_t*) nval;
+ uint32_t size;
+
+ MP4GetTrackBytesProperty(m->file, mux_data->track, "tkhd.matrix", &val, &size);
+ memcpy(nval, val, size);
+
+ const uint32_t ytranslation = (job->height - subHeight) * 0x10000;
+
+#ifdef WORDS_BIGENDIAN
+ ptr32[7] = ytranslation;
+#else
+ /* we need to switch the endianness, as the file format expects big endian */
+ ptr32[7] = ((ytranslation & 0x000000FF) << 24) + ((ytranslation & 0x0000FF00) << 8) +
+ ((ytranslation & 0x00FF0000) >> 8) + ((ytranslation & 0xFF000000) >> 24);
+#endif
+
+ MP4SetTrackBytesProperty(m->file, mux_data->track, "tkhd.matrix", nval, size);