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Diffstat (limited to 'libavcodec/gif.c')
-rw-r--r--libavcodec/gif.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index 7f602989e2..ec4be2749b 100644
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -4,20 +4,20 @@
* Copyright (c) 2002 Francois Revol
* Copyright (c) 2006 Baptiste Coudurier
*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
*
- * Libav is free software; you can redistribute it and/or
+ * 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.
*
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
@@ -63,7 +63,7 @@ static int gif_image_write_header(AVCodecContext *avctx,
uint8_t **bytestream, uint32_t *palette)
{
int i;
- unsigned int v;
+ unsigned int v, smallest_alpha = 0xFF, alpha_component = 0;
bytestream_put_buffer(bytestream, "GIF", 3);
bytestream_put_buffer(bytestream, "89a", 3);
@@ -78,6 +78,20 @@ static int gif_image_write_header(AVCodecContext *avctx,
for(i=0;i<256;i++) {
v = palette[i];
bytestream_put_be24(bytestream, v);
+ if (v >> 24 < smallest_alpha) {
+ smallest_alpha = v >> 24;
+ alpha_component = i;
+ }
+ }
+
+ if (smallest_alpha < 128) {
+ bytestream_put_byte(bytestream, 0x21); /* Extension Introducer */
+ bytestream_put_byte(bytestream, 0xf9); /* Graphic Control Label */
+ bytestream_put_byte(bytestream, 0x04); /* block length */
+ bytestream_put_byte(bytestream, 0x01); /* Transparent Color Flag */
+ bytestream_put_le16(bytestream, 0x00); /* no delay */
+ bytestream_put_byte(bytestream, alpha_component);
+ bytestream_put_byte(bytestream, 0x00);
}
return 0;
@@ -150,10 +164,8 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
uint8_t *outbuf_ptr, *end;
int ret;
- if ((ret = ff_alloc_packet(pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0) {
- av_log(avctx, AV_LOG_ERROR, "Error getting output packet.\n");
+ if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0)
return ret;
- }
outbuf_ptr = pkt->data;
end = pkt->data + pkt->size;