movtextdec.c: Add support for highlight and hilightcolor box

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

libavcodec/movtextdec.c

@@ -31,37 +31,165 @@
 #define STYLE_FLAG_ITALIC       (1<<1)
 #define STYLE_FLAG_UNDERLINE    (1<<2)
 
+#define STYL_BOX   (1<<0)
+#define HLIT_BOX   (1<<1)
+#define HCLR_BOX   (1<<2)
+
 typedef struct {
     uint16_t style_start;
     uint16_t style_end;
     uint8_t style_flag;
 } StyleBox;
 
+typedef struct {
+    uint16_t hlit_start;
+    uint16_t hlit_end;
+} HighlightBox;
+
+typedef struct {
+   uint8_t hlit_color[4];
+} HilightcolorBox;
+
+typedef struct {
+    StyleBox **s;
+    StyleBox *s_temp;
+    HighlightBox h;
+    HilightcolorBox c;
+    uint8_t box_flags;
+    uint16_t style_entries;
+    uint64_t tracksize;
+    int size_var;
+    int count_s;
+} MovTextContext;
+
+typedef struct {
+    uint32_t type;
+    size_t base_size;
+    int (*decode)(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt);
+} Box;
+
+static void mov_text_cleanup(MovTextContext *m)
+{
+    int i;
+    if (m->box_flags & STYL_BOX) {
+        for(i = 0; i < m->count_s; i++) {
+            av_freep(&m->s[i]);
+        }
+        av_freep(&m->s);
+    }
+}
+
+static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
+{
+    m->box_flags |= HLIT_BOX;
+    m->h.hlit_start = AV_RB16(tsmb);
+    tsmb += 2;
+    m->h.hlit_end = AV_RB16(tsmb);
+    tsmb += 2;
+    return 0;
+}
+
+static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
+{
+    m->box_flags |= HCLR_BOX;
+    memcpy(m->c.hlit_color, tsmb, 4);
+    tsmb += 4;
+    return 0;
+}
+
+static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
+{
+    int i;
+    m->style_entries = AV_RB16(tsmb);
+    tsmb += 2;
+    // A single style record is of length 12 bytes.
+    if (m->tracksize + m->size_var + 2 + m->style_entries * 12 > avpkt->size)
+        return -1;
+
+    m->box_flags |= STYL_BOX;
+    for(i = 0; i < m->style_entries; i++) {
+        m->s_temp = av_malloc(sizeof(*m->s_temp));
+        if (!m->s_temp) {
+            mov_text_cleanup(m);
+            return AVERROR(ENOMEM);
+        }
+        m->s_temp->style_start = AV_RB16(tsmb);
+        tsmb += 2;
+        m->s_temp->style_end = AV_RB16(tsmb);
+        tsmb += 2;
+        // fontID = AV_RB16(tsmb);
+        tsmb += 2;
+        m->s_temp->style_flag = AV_RB8(tsmb);
+        av_dynarray_add(&m->s, &m->count_s, m->s_temp);
+        if(!m->s) {
+            mov_text_cleanup(m);
+            return AVERROR(ENOMEM);
+        }
+        // fontsize = AV_RB8(tsmb);
+        tsmb += 2;
+        // text-color-rgba
+        tsmb += 4;
+    }
+    return 0;
+}
+
+static const Box box_types[] = {
+    { MKBETAG('s','t','y','l'), 2, decode_styl },
+    { MKBETAG('h','l','i','t'), 4, decode_hlit },
+    { MKBETAG('h','c','l','r'), 4, decode_hclr }
+};
+
+const static size_t box_count = FF_ARRAY_ELEMS(box_types);
+
 static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
-                        StyleBox **s, int style_entries)
+                        MovTextContext *m)
 {
     int i = 0;
     int text_pos = 0;
     while (text < text_end) {
-        for (i = 0; i < style_entries; i++) {
-            if (s[i]->style_flag && text_pos == s[i]->style_end) {
-                if (s[i]->style_flag & STYLE_FLAG_BOLD)
-                    av_bprintf(buf, "{\\b0}");
-                if (s[i]->style_flag & STYLE_FLAG_ITALIC)
-                    av_bprintf(buf, "{\\i0}");
-                if (s[i]->style_flag & STYLE_FLAG_UNDERLINE)
-                    av_bprintf(buf, "{\\u0}");
+        if (m->box_flags & STYL_BOX) {
+            for (i = 0; i < m->style_entries; i++) {
+                if (m->s[i]->style_flag && text_pos == m->s[i]->style_end) {
+                    if (m->s[i]->style_flag & STYLE_FLAG_BOLD)
+                        av_bprintf(buf, "{\\b0}");
+                    if (m->s[i]->style_flag & STYLE_FLAG_ITALIC)
+                        av_bprintf(buf, "{\\i0}");
+                    if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE)
+                        av_bprintf(buf, "{\\u0}");
+                }
+            }
+            for (i = 0; i < m->style_entries; i++) {
+                if (m->s[i]->style_flag && text_pos == m->s[i]->style_start) {
+                    if (m->s[i]->style_flag & STYLE_FLAG_BOLD)
+                        av_bprintf(buf, "{\\b1}");
+                    if (m->s[i]->style_flag & STYLE_FLAG_ITALIC)
+                        av_bprintf(buf, "{\\i1}");
+                    if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE)
+                        av_bprintf(buf, "{\\u1}");
+                }
             }
         }
-
-        for (i = 0; i < style_entries; i++) {
-            if (s[i]->style_flag && text_pos == s[i]->style_start) {
-                if (s[i]->style_flag & STYLE_FLAG_BOLD)
-                    av_bprintf(buf, "{\\b1}");
-                if (s[i]->style_flag & STYLE_FLAG_ITALIC)
-                    av_bprintf(buf, "{\\i1}");
-                if (s[i]->style_flag & STYLE_FLAG_UNDERLINE)
-                    av_bprintf(buf, "{\\u1}");
+        if (m->box_flags & HLIT_BOX) {
+            if (text_pos == m->h.hlit_start) {
+                /* If hclr box is present, set the secondary color to the color
+                 * specified. Otherwise, set primary color to white and secondary
+                 * color to black. These colors will come from TextSampleModifier
+                 * boxes in future and inverse video technique for highlight will
+                 * be implemented.
+                 */
+                if (m->box_flags & HCLR_BOX) {
+                    av_bprintf(buf, "{\\2c&H%02x%02x%02x&}", m->c.hlit_color[2],
+                                m->c.hlit_color[1], m->c.hlit_color[0]);
+                } else {
+                    av_bprintf(buf, "{\\1c&H000000&}{\\2c&HFFFFFF}");
+                }
+            }
+            if (text_pos == m->h.hlit_end) {
+                if (m->box_flags & HCLR_BOX) {
+                    av_bprintf(buf, "{\\2c&H000000}");
+                } else {
+                    av_bprintf(buf, "{\\1c&HFFFFFF&}{\\2c&H000000}");
+                }
             }
         }
 
@@ -96,17 +224,14 @@ static int mov_text_decode_frame(AVCodecContext *avctx,
                             void *data, int *got_sub_ptr, AVPacket *avpkt)
 {
     AVSubtitle *sub = data;
+    MovTextContext *m = avctx->priv_data;
     int ret, ts_start, ts_end;
     AVBPrint buf;
     char *ptr = avpkt->data;
     char *end;
-    //char *ptr_temp;
-    int text_length, tsmb_type, style_entries;
-    uint64_t tsmb_size, tracksize;
-    StyleBox **s = {0, };
-    StyleBox *s_temp;
+    int text_length, tsmb_type, ret_tsmb;
+    uint64_t tsmb_size;
     const uint8_t *tsmb;
-    int count, i, size_var;
 
     if (!ptr || avpkt->size < 2)
         return AVERROR_INVALIDDATA;
@@ -138,73 +263,49 @@ static int mov_text_decode_frame(AVCodecContext *avctx,
                             (AVRational){1,100});
 
     tsmb_size = 0;
-    tracksize = 2 + text_length;
+    m->tracksize = 2 + text_length;
+    m->style_entries = 0;
+    m->box_flags = 0;
+    m->count_s = 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) {
-        while (tracksize + 8 <= avpkt->size) {
+        while (m->tracksize + 8 <= avpkt->size) {
             // A box is a minimum of 8 bytes.
-            tsmb = ptr + tracksize - 2;
+            tsmb = ptr + m->tracksize - 2;
             tsmb_size = AV_RB32(tsmb);
             tsmb += 4;
             tsmb_type = AV_RB32(tsmb);
             tsmb += 4;
 
             if (tsmb_size == 1) {
-                if (tracksize + 16 > avpkt->size)
+                if (m->tracksize + 16 > avpkt->size)
                     break;
                 tsmb_size = AV_RB64(tsmb);
                 tsmb += 8;
-                size_var = 18;
+                m->size_var = 16;
             } else
-                size_var = 10;
-            //size_var is equal to 10 or 18 depending on the size of box
+                m->size_var = 8;
+            //size_var is equal to 8 or 16 depending on the size of box
 
-            if (tracksize + tsmb_size > avpkt->size)
+            if (m->tracksize + tsmb_size > avpkt->size)
                 break;
 
-            if (tsmb_type == MKBETAG('s','t','y','l')) {
-                if (tracksize + size_var > avpkt->size)
-                    break;
-                style_entries = AV_RB16(tsmb);
-                tsmb += 2;
-
-                // A single style record is of length 12 bytes.
-                if (tracksize + size_var + style_entries * 12 > avpkt->size)
-                    break;
-                count = 0;
-
-                for(i = 0; i < style_entries; i++) {
-                    s_temp = av_malloc(sizeof(*s_temp));
-                    if (!s_temp)
-                        goto error;
-
-                    s_temp->style_start = AV_RB16(tsmb);
-                    tsmb += 2;
-                    s_temp->style_end = AV_RB16(tsmb);
-                    tsmb += 2;
-                    // fontID = AV_RB16(tsmb);
-                    tsmb += 2;
-                    s_temp->style_flag = AV_RB8(tsmb);
-                    av_dynarray_add(&s, &count, s_temp);
-                    if(!s)
-                        goto error;
-                    //fontsize=AV_RB8(tsmb);
-                    tsmb += 2;
-                    // text-color-rgba
-                    tsmb += 4;
-                }
-                text_to_ass(&buf, ptr, end, s, style_entries);
-
-                for(i = 0; i < count; i++) {
-                    av_freep(&s[i]);
+            for (size_t i = 0; i < box_count; i++) {
+                if (tsmb_type == box_types[i].type) {
+                    if (m->tracksize + m->size_var + box_types[i].base_size > avpkt->size)
+                        break;
+                    ret_tsmb = box_types[i].decode(tsmb, m, avpkt);
+                    if (ret_tsmb == -1)
+                        break;
                 }
-                av_freep(&s);
             }
-            tracksize = tracksize + tsmb_size;
+            m->tracksize = m->tracksize + tsmb_size;
         }
+        text_to_ass(&buf, ptr, end, m);
+        mov_text_cleanup(m);
     } else
-        text_to_ass(&buf, ptr, end, NULL, 0);
+        text_to_ass(&buf, ptr, end, m);
 
     ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end - ts_start);
     av_bprint_finalize(&buf, NULL);
@@ -212,16 +313,6 @@ static int mov_text_decode_frame(AVCodecContext *avctx,
         return ret;
     *got_sub_ptr = sub->num_rects > 0;
     return avpkt->size;
-
-error:
-    for(i = 0; i < count; i++) {
-        av_freep(&s[i]);
-    }
-    av_freep(&s);
-    if (s_temp)
-        av_freep(&s_temp);
-    av_bprint_finalize(&buf, NULL);
-    return AVERROR(ENOMEM);
 }
 
 AVCodec ff_movtext_decoder = {
@@ -229,6 +320,7 @@ AVCodec ff_movtext_decoder = {
     .long_name    = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
     .type         = AVMEDIA_TYPE_SUBTITLE,
     .id           = AV_CODEC_ID_MOV_TEXT,
+    .priv_data_size = sizeof(MovTextContext),
     .init         = mov_text_init,
     .decode       = mov_text_decode_frame,
 };