movtextdec: Use default style information from movtext header

Signed-off-by: Niklesh <niklesh.lalwani@iitb.ac.in>

libavcodec/movtextdec.c

@@ -37,6 +37,27 @@
 #define HLIT_BOX   (1<<1)
 #define HCLR_BOX   (1<<2)
 
+#define BOTTOM_LEFT     1
+#define BOTTOM_CENTER   2
+#define BOTTOM_RIGHT    3
+#define MIDDLE_LEFT     4
+#define MIDDLE_CENTER   5
+#define MIDDLE_RIGHT    6
+#define TOP_LEFT        7
+#define TOP_CENTER      8
+#define TOP_RIGHT       9
+
+typedef struct {
+    char *font;
+    int fontsize;
+    int color;
+    int back_color;
+    int bold;
+    int italic;
+    int underline;
+    int alignment;
+} MovTextDefault;
+
 typedef struct {
     uint16_t fontID;
     char *font;
@@ -66,6 +87,7 @@ typedef struct {
     HilightcolorBox c;
     FontRecord **ftab;
     FontRecord *ftab_temp;
+    MovTextDefault d;
     uint8_t box_flags;
     uint16_t style_entries, ftab_entries;
     uint64_t tracksize;
@@ -106,6 +128,9 @@ static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
 {
     char *tx3g_ptr = avctx->extradata;
     int i, box_size, font_length;
+    int8_t v_align, h_align;
+    int style_fontID;
+    StyleBox s_default;
 
     m->count_f = 0;
     m->ftab_entries = 0;
@@ -116,13 +141,52 @@ static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
     // Display Flags
     tx3g_ptr += 4;
     // Alignment
-    tx3g_ptr += 2;
+    h_align = *tx3g_ptr++;
+    v_align = *tx3g_ptr++;
+    if (h_align == 0) {
+        if (v_align == 0)
+            m->d.alignment = TOP_LEFT;
+        if (v_align == 1)
+            m->d.alignment = MIDDLE_LEFT;
+        if (v_align == -1)
+            m->d.alignment = BOTTOM_LEFT;
+    }
+    if (h_align == 1) {
+        if (v_align == 0)
+            m->d.alignment = TOP_CENTER;
+        if (v_align == 1)
+            m->d.alignment = MIDDLE_CENTER;
+        if (v_align == -1)
+            m->d.alignment = BOTTOM_CENTER;
+    }
+    if (h_align == -1) {
+        if (v_align == 0)
+            m->d.alignment = TOP_RIGHT;
+        if (v_align == 1)
+            m->d.alignment = MIDDLE_RIGHT;
+        if (v_align == -1)
+            m->d.alignment = BOTTOM_RIGHT;
+    }
     // Background Color
+    memcpy(&m->d.back_color, tx3g_ptr, 3);
     tx3g_ptr += 4;
     // BoxRecord
     tx3g_ptr += 8;
     // StyleRecord
-    tx3g_ptr += 12;
+    tx3g_ptr += 4;
+    // fontID
+    style_fontID = AV_RB16(tx3g_ptr);
+    tx3g_ptr += 2;
+    // face-style-flags
+    s_default.style_flag = *tx3g_ptr++;
+    m->d.bold = s_default.style_flag & STYLE_FLAG_BOLD;
+    m->d.italic = s_default.style_flag & STYLE_FLAG_ITALIC;
+    m->d.underline = s_default.style_flag & STYLE_FLAG_UNDERLINE;
+    // fontsize
+    m->d.fontsize = *tx3g_ptr++;
+    // Primary color
+    memcpy(&m->d.color, tx3g_ptr, 3);
+    tx3g_ptr += 4;
     // FontRecord
     // FontRecord Size
     tx3g_ptr += 4;
@@ -169,6 +233,10 @@ static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
         }
         tx3g_ptr = tx3g_ptr + font_length;
     }
+    for (i = 0; i < m->ftab_entries; i++) {
+        if (style_fontID == m->ftab[i]->fontID)
+            m->d.font = m->ftab[i]->font;
+    }
     return 0;
 }
 
@@ -312,9 +380,15 @@ static int mov_text_init(AVCodecContext *avctx) {
      * it's very common to find files where the default style is broken
      * and respecting it results in a worse experience than ignoring it.
      */
+    int ret;
     MovTextContext *m = avctx->priv_data;
-    mov_text_tx3g(avctx, m);
-    return ff_ass_subtitle_header_default(avctx);
+    ret = mov_text_tx3g(avctx, m);
+    if (ret == 0) {
+        return ff_ass_subtitle_header(avctx, m->d.font, m->d.fontsize, m->d.color,
+                                m->d.back_color, m->d.bold, m->d.italic,
+                                m->d.underline, m->d.alignment);
+    } else
+        return ff_ass_subtitle_header_default(avctx);
 }
 
 static int mov_text_decode_frame(AVCodecContext *avctx,