In order to support multiple IDAT of fdAT chunks following an fcTL one,
transmit all the chunks between two fcTL ones (or between fcTL and IEND
one).
---
libavformat/apngdec.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c
index 1e0f1c7..756cdd1 100644
--- a/libavformat/apngdec.c
+++ b/libavformat/apngdec.c
@@ -325,8 +325,6 @@ static int apng_read_packet(AVFormatContext *s, AVPacket
*pkt)
* and needed next:
* 4 (length)
* 4 (tag (must be fdAT or IDAT))
- *
- * TODO: support multiple fdAT following an fcTL
*/
/* if num_play is not 1, then the seekback is already guaranteed */
if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 46)) < 0)
@@ -350,15 +348,35 @@ static int apng_read_packet(AVFormatContext *s, AVPacket
*pkt)
tag != MKTAG('I', 'D', 'A', 'T'))
return AVERROR_INVALIDDATA;
- if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0)
- return ret;
-
size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */;
if (size > INT_MAX)
return AVERROR(EINVAL);
- if ((ret = av_get_packet(pb, pkt, size)) < 0)
+ if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0 ||
+ (ret = av_append_packet(pb, pkt, size)) < 0)
+ return ret;
+
+ if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
return ret;
+
+ len = avio_rb32(pb);
+ tag = avio_rl32(pb);
+ while (tag &&
+ tag != MKTAG('f', 'c', 'T', 'L') &&
+ tag != MKTAG('I', 'E', 'N', 'D')) {
+ if (len > 0x7fffffff)
+ return AVERROR_INVALIDDATA;
+ if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
+ (ret = av_append_packet(pb, pkt, len + 12)) < 0)
+ return ret;
+ if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
+ return ret;
+ len = avio_rb32(pb);
+ tag = avio_rl32(pb);
+ }
+ if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0)
+ return ret;
+
if (ctx->is_key_frame)
pkt->flags |= AV_PKT_FLAG_KEY;
return ret;
--
2.2.0.rc2.23.gca0107e
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