When the dimensions are the entire frame ones, and the dispose operation
is to reset to background, or the new frame overwrites the new one, then
consider the frame as a key one.
---
libavformat/apng.h | 41 +++++++++++++++++++++++++++++++++++++++++
libavformat/apngdec.c | 6 +++++-
2 files changed, 46 insertions(+), 1 deletion(-)
create mode 100644 libavformat/apng.h
diff --git a/libavformat/apng.h b/libavformat/apng.h
new file mode 100644
index 0000000..2abf011
--- /dev/null
+++ b/libavformat/apng.h
@@ -0,0 +1,41 @@
+/*
+ * APNG common header
+ * Copyright (c) 2014 Benoit Fouet
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * APNG common header
+ */
+
+#ifndef AVFORMAT_APNG_H
+#define AVFORMAT_APNG_H
+
+enum {
+ APNG_DISPOSE_OP_NONE = 0,
+ APNG_DISPOSE_OP_BACKGROUND = 1,
+ APNG_DISPOSE_OP_PREVIOUS = 2,
+};
+
+enum {
+ APNG_BLEND_OP_SOURCE = 0,
+ APNG_BLEND_OP_OVER = 1,
+};
+
+#endif /* AVFORMAT_APNG_H */
diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c
index d766a87..dac71f1 100644
--- a/libavformat/apngdec.c
+++ b/libavformat/apngdec.c
@@ -26,6 +26,7 @@
* @see http://www.w3.org/TR/PNG
*/
+#include "apng.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
@@ -298,7 +299,10 @@ static int decode_fctl_chunk(AVFormatContext *s,
APNGDemuxContext *ctx, AVPacket
return AVERROR_INVALIDDATA;
ctx->is_key_frame = 0;
} else {
- ctx->is_key_frame = 1;
+ if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS)
+ dispose_op = APNG_DISPOSE_OP_BACKGROUND;
+ ctx->is_key_frame = dispose_op == APNG_DISPOSE_OP_BACKGROUND ||
+ blend_op == APNG_BLEND_OP_SOURCE;
}
return 0;
--
2.2.0.rc2.23.gca0107e
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