[FFmpeg-cvslog] avcodec/jpeg2000dec: fix tilepart processing

[Osamu Watanabe]

ffmpeg | branch: master | Osamu Watanabe <owatanab at es.takushoku-u.ac.jp> | Fri Jun  7 09:25:49 2024 +0900| [6f4a95cfb8e6ed97fdd1027251181caded44860f] | committer: Pierre-Anthony Lemieux

avcodec/jpeg2000dec: fix tilepart processing

Fix http://trac.ffmpeg.org/ticket/10121

Signed-off-by: Pierre-Anthony Lemieux <pal at palemieux.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6f4a95cfb8e6ed97fdd1027251181caded44860f
---

 libavcodec/jpeg2000dec.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index d15502a527..091931b1ff 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1005,6 +1005,7 @@ static inline void select_header(Jpeg2000DecoderContext *s, const Jpeg2000Tile *
 {
     s->g = tile->tile_part[*tp_index].header_tpg;
     if (bytestream2_get_bytes_left(&s->g) == 0 && s->bit_index == 8) {
+        av_log(s->avctx, AV_LOG_WARNING, "Packet header bytes in PPM marker segment is too short.\n");
         if (*tp_index < FF_ARRAY_ELEMS(tile->tile_part) - 1) {
             s->g = tile->tile_part[++(*tp_index)].tpg;
         }
@@ -1014,10 +1015,18 @@ static inline void select_header(Jpeg2000DecoderContext *s, const Jpeg2000Tile *
 static inline void select_stream(Jpeg2000DecoderContext *s, const Jpeg2000Tile *tile,
                                  int *tp_index, const Jpeg2000CodingStyle *codsty)
 {
+    int32_t is_endof_tp;
+
     s->g = tile->tile_part[*tp_index].tpg;
-    if (bytestream2_get_bytes_left(&s->g) == 0 && s->bit_index == 8) {
+    is_endof_tp = bytestream2_get_bytes_left(&s->g) == 0 && s->bit_index == 8;
+    // Following while loop is necessary because a tilepart may include only SOD marker.
+    // Such a tilepart has neither packet header nor compressed data.
+    while (is_endof_tp) {
         if (*tp_index < FF_ARRAY_ELEMS(tile->tile_part) - 1) {
             s->g = tile->tile_part[++(*tp_index)].tpg;
+            is_endof_tp = bytestream2_get_bytes_left(&s->g) == 0 && s->bit_index == 8;
+        } else {
+            is_endof_tp = 0;
         }
     }
     if (codsty->csty & JPEG2000_CSTY_SOP) {