Document ff_des_encdec

[ffmpeg] / libavcodec / xsubdec.c

diff --git a/libavcodec/xsubdec.c b/libavcodec/xsubdec.c
index 2a858f60b45b2031757b205d331dc06fd8bae3b0..609f59b3510178a25fb1fc63ddd97810c5d505b6 100644 (file)
--- a/libavcodec/xsubdec.c
+++ b/libavcodec/xsubdec.c
@@ -1,3 +1,23 @@
+/*
+ * XSUB subtitle decoder
+ * Copyright (c) 2007 Reimar Döffinger
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
 #include "avcodec.h"
 #include "bitstream.h"
 #include "bytestream.h"
@@ -10,7 +30,7 @@ static int decode_init(AVCodecContext *avctx) {
 static const uint8_t tc_offsets[9] = { 0, 1, 3, 4, 6, 7, 9, 10, 11 };
 static const uint8_t tc_muls[9] = { 10, 6, 10, 6, 10, 6, 10, 10, 1 };
 
-static uint64_t parse_timecode(AVCodecContext *avctx, uint8_t *buf) {
+static uint64_t parse_timecode(uint8_t *buf) {
     int i;
     int64_t ms = 0;
     if (buf[2] != ':' || buf[5] != ':' || buf[8] != '.')
@@ -20,12 +40,9 @@ static uint64_t parse_timecode(AVCodecContext *avctx, uint8_t *buf) {
         if (c > 9) return AV_NOPTS_VALUE;
         ms = (ms + c) * tc_muls[i];
     }
-    ms = av_rescale_q(ms, (AVRational){1, 1000}, avctx->time_base);
     return ms;
 }
 
-static const uint8_t runbits[8] = { 14, 14, 10, 10, 6, 6, 2, 2 };
-
 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                         uint8_t *buf, int buf_size) {
     AVSubtitle *sub = data;
@@ -45,8 +62,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         av_log(avctx, AV_LOG_ERROR, "invalid time code\n");
         return -1;
     }
-    sub->start_display_time = parse_timecode(avctx, buf +  1);
-    sub->end_display_time   = parse_timecode(avctx, buf + 14);
+    sub->start_display_time = parse_timecode(buf +  1);
+    sub->end_display_time   = parse_timecode(buf + 14);
     buf += 27;
 
     // read header
@@ -77,15 +94,20 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     // read palette
     for (i = 0; i < sub->rects[0].nb_colors; i++)
         sub->rects[0].rgba_palette[i] = bytestream_get_be24(&buf);
+    // make all except background (first entry) non-transparent
+    for (i = 1; i < sub->rects[0].nb_colors; i++)
+        sub->rects[0].rgba_palette[i] |= 0xff000000;
 
     // process RLE-compressed data
     rlelen = FFMIN(rlelen, buf_end - buf);
     init_get_bits(&gb, buf, rlelen * 8);
     bitmap = sub->rects[0].bitmap;
     for (y = 0; y < h; y++) {
+        // interlaced: do odd lines
+        if (y == (h + 1) / 2) bitmap = sub->rects[0].bitmap + w;
         for (x = 0; x < w; ) {
             int log2 = ff_log2_tab[show_bits(&gb, 8)];
-            int run = get_bits(&gb, runbits[log2]);
+            int run = get_bits(&gb, 14 - 4 * (log2 >> 1));
             int colour = get_bits(&gb, 2);
             run = FFMIN(run, w - x);
             // run length 0 means till end of row
@@ -94,6 +116,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
             bitmap += run;
             x += run;
         }
+        // interlaced, skip every second line
+        bitmap += w;
         align_get_bits(&gb);
     }
     *data_size = 1;