diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
index a208e19b95..6a3018dd4e 100644
--- a/libavcodec/ccaption_dec.c
+++ b/libavcodec/ccaption_dec.c
@@ -459,6 +459,7 @@ static int capture_screen(CCaptionSubContext *ctx)
         if (CHECK_FLAG(screen->row_used, i)) {
             const char *row = screen->characters[i];
             const char *charset = screen->charsets[i];
+
             j = 0;
             while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
                 j++;
@@ -476,13 +477,19 @@ static int capture_screen(CCaptionSubContext *ctx)
             const char *color = screen->colors[i];
             const char *charset = screen->charsets[i];
             const char *override;
-            int x, y, seen_char = 0;
+            int x, y, row_end, seen_char = 0;
             j = 0;
 
             /* skip leading space */
             while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN && j < tab)
                 j++;
 
+            /* skip trailing space */
+            row_end = SCREEN_COLUMNS-1;
+            while (row_end >= 0 && row[row_end] == ' ' && charset[row_end] == CCSET_BASIC_AMERICAN) {
+                row_end--;
+            }
+
             x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
             y = ASS_DEFAULT_PLAYRESY * (0.1 + 0.0533 * i);
             av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
@@ -490,7 +497,7 @@ static int capture_screen(CCaptionSubContext *ctx)
             for (; j < SCREEN_COLUMNS; j++) {
                 const char *e_tag = "", *s_tag = "", *c_tag = "", *b_tag = "";
 
-                if (row[j] == 0)
+                if (j > row_end || row[j] == 0)
                     break;
 
                 if (prev_font != font[j]) {
@@ -624,7 +631,8 @@ static void handle_textattr(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
     ctx->cursor_font = pac2_attribs[i][1];
 
     SET_FLAG(screen->row_used, ctx->cursor_row);
-    write_char(ctx, screen, ' ');
+
+    ctx->cursor_column++;
 }
 
 static void handle_pac(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
@@ -633,8 +641,7 @@ static void handle_pac(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
         11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10
     };
     const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );
-    struct Screen *screen = get_writing_screen(ctx);
-    int indent, i;
+    int indent;
 
     if (row_map[index] <= 0) {
         av_log(ctx, AV_LOG_DEBUG, "Invalid pac index encountered\n");
@@ -644,14 +651,11 @@ static void handle_pac(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
     lo &= 0x1f;
 
     ctx->cursor_row = row_map[index] - 1;
-    ctx->cursor_color =  pac2_attribs[lo][0];
+    ctx->cursor_color = pac2_attribs[lo][0];
     ctx->cursor_font = pac2_attribs[lo][1];
     ctx->cursor_charset = CCSET_BASIC_AMERICAN;
-    ctx->cursor_column = 0;
     indent = pac2_attribs[lo][2];
-    for (i = 0; i < indent; i++) {
-        write_char(ctx, screen, ' ');
-    }
+    ctx->cursor_column = indent;
 }
 
 static int handle_edm(CCaptionSubContext *ctx)
@@ -667,6 +671,14 @@ static int handle_edm(CCaptionSubContext *ctx)
     screen->row_used = 0;
     ctx->bg_color = CCCOL_BLACK;
 
+    for (int i = 0; i < SCREEN_ROWS+1; ++i) {
+        memset(screen->characters[i], ' ',                  SCREEN_COLUMNS);
+        memset(screen->colors[i],     CCCOL_WHITE,          SCREEN_COLUMNS);
+        memset(screen->bgs[i],        CCCOL_BLACK,          SCREEN_COLUMNS);
+        memset(screen->charsets[i],   CCSET_BASIC_AMERICAN, SCREEN_COLUMNS);
+        memset(screen->fonts[i],      CCFONT_REGULAR,       SCREEN_COLUMNS);
+    }
+
     // In realtime mode, emit an empty caption so the last one doesn't
     // stay on the screen.
     if (ctx->real_time)
@@ -687,6 +699,7 @@ static int handle_eoc(CCaptionSubContext *ctx)
         ret = handle_edm(ctx);
 
     ctx->cursor_column = 0;
+    ctx->cursor_row = 0;
 
     // In realtime mode, we display the buffered contents (after
     // flipping the buffer to active above) as soon as EOC arrives.
@@ -731,7 +744,6 @@ static void handle_char(CCaptionSubContext *ctx, char hi, char lo)
     if (lo) {
         write_char(ctx, screen, lo);
     }
-    write_char(ctx, screen, 0);
 
     if (ctx->mode != CCMODE_POPON)
         ctx->screen_touched = 1;
@@ -823,11 +835,8 @@ static int process_cc608(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
         handle_char(ctx, hi, lo);
         ctx->prev_cmd[0] = ctx->prev_cmd[1] = 0;
     } else if (hi == 0x17 && lo >= 0x21 && lo <= 0x23) {
-        int i;
         /* Tab offsets (spacing) */
-        for (i = 0; i < lo - 0x20; i++) {
-            handle_char(ctx, ' ', 0);
-        }
+        ctx->cursor_column += lo - 0x20;
     } else {
         /* Ignoring all other non data code */
         ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);
