Merge remote-tracking branch 'qatar/master'

[ffmpeg] / libavcodec / xsubdec.c

diff --git a/libavcodec/xsubdec.c b/libavcodec/xsubdec.c
index d24588b8d99a60faf0caed53aa427b1964ca6a52..9289a2554e3a3596dd071fb4c1f369a1e7452969 100644 (file)
--- a/libavcodec/xsubdec.c
+++ b/libavcodec/xsubdec.c
@@ -51,11 +51,10 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     AVSubtitle *sub = data;
     const uint8_t *buf_end = buf + buf_size;
     uint8_t *bitmap;
-    int w, h, x, y, rlelen, i;
+    int w, h, x, y, i;
     int64_t packet_time = 0;
     GetBitContext gb;
-
-    memset(sub, 0, sizeof(*sub));
+    int has_alpha = avctx->codec_tag == MKTAG('D','X','S','A');
 
     // check that at least header fits
     if (buf_size < 27 + 7 * 2 + 4 * 3) {
@@ -84,7 +83,11 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     // skip bottom right position, it gives no new information
     bytestream_get_le16(&buf);
     bytestream_get_le16(&buf);
-    rlelen = bytestream_get_le16(&buf);
+    // The following value is supposed to indicate the start offset
+    // (relative to the palette) of the data for the second field,
+    // however there are files  where it has a bogus value and thus
+    // we just ignore it
+    bytestream_get_le16(&buf);
 
     // allocate sub and set values
     sub->rects =  av_mallocz(sizeof(*sub->rects));
@@ -102,12 +105,11 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     for (i = 0; i < sub->rects[0]->nb_colors; i++)
         ((uint32_t*)sub->rects[0]->pict.data[1])[i] = bytestream_get_be24(&buf);
     // make all except background (first entry) non-transparent
-    for (i = 1; i < sub->rects[0]->nb_colors; i++)
-        ((uint32_t*)sub->rects[0]->pict.data[1])[i] |= 0xff000000;
+    for (i = 0; i < sub->rects[0]->nb_colors; i++)
+        ((uint32_t*)sub->rects[0]->pict.data[1])[i] |= (has_alpha ? *buf++ : (i ? 0xff : 0)) << 24;
 
     // process RLE-compressed data
-    rlelen = FFMIN(rlelen, buf_end - buf);
-    init_get_bits(&gb, buf, rlelen * 8);
+    init_get_bits(&gb, buf, (buf_end - buf) * 8);
     bitmap = sub->rects[0]->pict.data[0];
     for (y = 0; y < h; y++) {
         // interlaced: do odd lines