[FFmpeg-devel] [PATCH] movtextdec.c: Add support for font names

[Niklesh Lalwani]

From: Niklesh <niklesh.lalwani at iitb.ac.in>

The font names are extracted from the font table, present in text sample entry. More than one fonts can be present, which is taken care of in the patch.

Signed-off-by: Niklesh <niklesh.lalwani at iitb.ac.in>
---
 libavcodec/movtextdec.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 83 insertions(+), 3 deletions(-)

diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c
index 869358c..7d4dead 100644
--- a/libavcodec/movtextdec.c
+++ b/libavcodec/movtextdec.c
@@ -36,10 +36,17 @@
 #define HCLR_BOX   (1<<2)
 
 typedef struct {
+    uint16_t fontID;
+    uint8_t font_name_length;
+    uint8_t font[20];
+} FontRecord;
+
+typedef struct {
     uint16_t style_start;
     uint16_t style_end;
     uint8_t style_flag;
     uint8_t fontsize;
+    uint16_t style_fontID;
 } StyleBox;
 
 typedef struct {
@@ -56,11 +63,13 @@ typedef struct {
     StyleBox *s_temp;
     HighlightBox h;
     HilightcolorBox c;
+    FontRecord **ftab;
+    FontRecord *ftab_temp;
     uint8_t box_flags;
-    uint16_t style_entries;
+    uint16_t style_entries, ftab_entries;
     uint64_t tracksize;
     int size_var;
-    int count_s;
+    int count_s, count_f;
 } MovTextContext;
 
 typedef struct {
@@ -80,6 +89,56 @@ static void mov_text_cleanup(MovTextContext *m)
     }
 }
 
+static void mov_text_cleanup_ftab(MovTextContext *m)
+{
+    int i;
+    for(i = 0; i < m->count_f; i++) {
+        av_freep(&m->ftab[i]);
+    }
+    av_freep(&m->ftab);
+}
+
+static int mov_text_t3xg(AVCodecContext *avctx, MovTextContext *m)
+{
+    char *t3xg_ptr = avctx->extradata;
+    int i;
+    // Display Flags
+    t3xg_ptr += 4;
+    // Alignment
+    t3xg_ptr += 2;
+    // Background Color
+    t3xg_ptr += 4;
+    // BoxRecord
+    t3xg_ptr += 8;
+    // StyleRecord
+    t3xg_ptr += 12;
+    // FontRecord
+    // FontRecord Size
+    t3xg_ptr += 4;
+    // ftab
+    t3xg_ptr += 4;
+    m->ftab_entries = AV_RB16(t3xg_ptr);
+    t3xg_ptr += 2;
+    for (i = 0; i < m->ftab_entries; i++) {
+        m->ftab_temp = av_malloc(sizeof(*m->ftab_temp));
+        if (!m->ftab_temp) {
+            mov_text_cleanup_ftab(m);
+            return AVERROR(ENOMEM);
+        }
+        m->ftab_temp->fontID = AV_RB16(t3xg_ptr);
+        t3xg_ptr += 2;
+        m->ftab_temp->font_name_length = *t3xg_ptr++;
+        memcpy(m->ftab_temp->font, t3xg_ptr, m->ftab_temp->font_name_length);
+        av_dynarray_add(&m->ftab, &m->count_f, m->ftab_temp);
+        if (!m->ftab) {
+            mov_text_cleanup_ftab(m);
+            return AVERROR(ENOMEM);
+        }
+        t3xg_ptr += 10;
+    }
+    return 0;
+}
+
 static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
 {
     m->box_flags |= HLIT_BOX;
@@ -118,7 +177,7 @@ static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
         tsmb += 2;
         m->s_temp->style_end = AV_RB16(tsmb);
         tsmb += 2;
-        // fontID = AV_RB16(tsmb);
+        m->s_temp->style_fontID = AV_RB16(tsmb);
         tsmb += 2;
         m->s_temp->style_flag = AV_RB8(tsmb);
         tsmb++;
@@ -147,6 +206,8 @@ static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
                         MovTextContext *m)
 {
     int i = 0;
+    int j = 0;
+    int k = 0;
     int text_pos = 0;
     while (text < text_end) {
         if (m->box_flags & STYL_BOX) {
@@ -164,6 +225,14 @@ static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
                     if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE)
                         av_bprintf(buf, "{\\u1}");
                     av_bprintf(buf, "{\\fs%d}", m->s[i]->fontsize);
+                    av_bprintf(buf, "{\\fn");
+                    for (j = 0; j < m->ftab_entries; j++) {
+                        if (m->s[i]->style_fontID == m->ftab[j]->fontID) {
+                            for (k = 0; k < m->ftab[0]->font_name_length; k++)
+                                av_bprintf(buf, "%c", m->ftab[j]->font[k]);
+                        }
+                    }
+                    av_bprintf(buf, "}");
                 }
             }
         }
@@ -215,6 +284,8 @@ 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.
      */
+    MovTextContext *m = avctx->priv_data;
+    mov_text_t3xg(avctx, m);
     return ff_ass_subtitle_header_default(avctx);
 }
 
@@ -265,6 +336,7 @@ static int mov_text_decode_frame(AVCodecContext *avctx,
     m->style_entries = 0;
     m->box_flags = 0;
     m->count_s = 0;
+    m->count_f = 0;
     // Note that the spec recommends lines be no longer than 2048 characters.
     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
     if (text_length + 2 != avpkt->size) {
@@ -313,6 +385,13 @@ static int mov_text_decode_frame(AVCodecContext *avctx,
     return avpkt->size;
 }
 
+static int mov_text_decode_close(AVCodecContext *avctx)
+{
+    MovTextContext *m = avctx->priv_data;
+    mov_text_cleanup_ftab(m);
+    return 0;
+}
+
 AVCodec ff_movtext_decoder = {
     .name         = "mov_text",
     .long_name    = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
@@ -321,4 +400,5 @@ AVCodec ff_movtext_decoder = {
     .priv_data_size = sizeof(MovTextContext),
     .init         = mov_text_init,
     .decode       = mov_text_decode_frame,
+    .close        = mov_text_decode_close,
 };
-- 
1.9.1