dvbsub: add dvb_encode_rle8()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/dvbsub.c

@@ -194,6 +194,61 @@ static void dvb_encode_rle4(uint8_t **pq,
     *pq = q;
 }
 
+static void dvb_encode_rle8(uint8_t **pq,
+                            const uint8_t *bitmap, int linesize,
+                            int w, int h)
+{
+    uint8_t *q;
+    int x, y, len, x1, f, color;
+
+    q = *pq;
+
+    for (y = 0; y < h; y++) {
+        *q++ = 0x12;
+
+        x = 0;
+        f = 0;
+        while (x < w) {
+            x1 = x;
+            color = bitmap[x1++];
+            while (x1 < w && bitmap[x1] == color)
+                x1++;
+            len = x1 - x;
+            if (len == 1 && color) {
+                // 00000001 to 11111111           1 pixel in colour x
+                *q++ = color;
+            } else {
+                if (color == 0x00) {
+                    // 00000000 0LLLLLLL          L pixels (1-127) in colour 0 (L > 0)
+                    len = FFMIN(len, 127);
+                    *q++ = 0x00;
+                    *q++ = len;
+                } else if (len > 2) {
+                    // 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
+                    len = FFMIN(len, 127);
+                    *q++ = 0x00;
+                    *q++ = 0x80+len;
+                    *q++ = color;
+                }
+                else if (len == 2) {
+                    *q++ = color;
+                    *q++ = color;
+                } else {
+                    *q++ = color;
+                    len = 1;
+                }
+            }
+            x += len;
+        }
+        /* end of line */
+        // 00000000 00000000 end of 8-bit/pixel_code_string
+        *q++ = 0x00;
+        *q++ = 0x00;
+        bitmap += linesize;
+    }
+    *pq = q;
+}
+
 static int encode_dvb_subtitles(DVBSubtitleContext *s,
                                 uint8_t *outbuf, AVSubtitle *h)
 {
@@ -245,6 +300,9 @@ static int encode_dvb_subtitles(DVBSubtitleContext *s,
             } else if (h->rects[clut_id]->nb_colors <= 16) {
                 /* 4 bpp, standard encoding */
                 bpp_index = 1;
+            } else if (h->rects[clut_id]->nb_colors <= 256) {
+                /* 8 bpp, standard encoding */
+                bpp_index = 2;
             } else {
                 return -1;
             }
@@ -332,6 +390,9 @@ static int encode_dvb_subtitles(DVBSubtitleContext *s,
             } else if (h->rects[object_id]->nb_colors <= 16) {
                 /* 4 bpp, standard encoding */
                 dvb_encode_rle = dvb_encode_rle4;
+            } else if (h->rects[object_id]->nb_colors <= 256) {
+                /* 8 bpp, standard encoding */
+                dvb_encode_rle = dvb_encode_rle8;
             } else {
                 return -1;
             }