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remove dead netscape loop header code in gif encoder, patch by Daniel Verkamp, daniel at drv dot nu

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Originally committed as revision 17094 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Daniel Verkamp
2009-02-09 08:11:08 +00:00
committed by Baptiste Coudurier
parent 505aa6c91d
commit c33030bd7b
1 changed files with 2 additions and 38 deletions
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40
libavcodec/gif.c
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@@ -53,10 +53,6 @@
/* bitstream minipacket size */ /* bitstream minipacket size */
#define GIF_CHUNKS 100 #define GIF_CHUNKS 100
/* slows down the decoding (and some browsers don't like it) */
/* update on the 'some browsers don't like it issue from above: this was probably due to missing 'Data Sub-block Terminator' (byte 19) in the app_header */
#define GIF_ADD_APP_HEADER // required to enable looping of animated gif
typedef struct { typedef struct {
unsigned char r; unsigned char r;
unsigned char g; unsigned char g;
@@ -111,7 +107,7 @@ static const rgb_triplet gif_clut[216] = {
/* GIF header */ /* GIF header */
static int gif_image_write_header(uint8_t **bytestream, static int gif_image_write_header(uint8_t **bytestream,
int width, int height, int loop_count, int width, int height,
uint32_t *palette) uint32_t *palette)
{ {
int i; int i;
@@ -138,38 +134,6 @@ static int gif_image_write_header(uint8_t **bytestream,
} }
} }
/* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated gif
see http://members.aol.com/royalef/gifabout.htm#net-extension
byte 1 : 33 (hex 0x21) GIF Extension code
byte 2 : 255 (hex 0xFF) Application Extension Label
byte 3 : 11 (hex (0x0B) Length of Application Block
(eleven bytes of data to follow)
bytes 4 to 11 : "NETSCAPE"
bytes 12 to 14 : "2.0"
byte 15 : 3 (hex 0x03) Length of Data Sub-Block
(three bytes of data to follow)
byte 16 : 1 (hex 0x01)
bytes 17 to 18 : 0 to 65535, an unsigned integer in
lo-hi byte format. This indicate the
number of iterations the loop should
be executed.
bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator
*/
/* application extension header */
#ifdef GIF_ADD_APP_HEADER
if (loop_count >= 0 && loop_count <= 65535) {
bytestream_put_byte(bytestream, 0x21);
bytestream_put_byte(bytestream, 0xff);
bytestream_put_byte(bytestream, 0x0b);
bytestream_put_buffer(bytestream, "NETSCAPE2.0", 11); // bytes 4 to 14
bytestream_put_byte(bytestream, 0x03); // byte 15
bytestream_put_byte(bytestream, 0x01); // byte 16
bytestream_put_le16(bytestream, (uint16_t)loop_count);
bytestream_put_byte(bytestream, 0x00); // byte 19
}
#endif
return 0; return 0;
} }
@@ -270,7 +234,7 @@ static int gif_encode_frame(AVCodecContext *avctx, unsigned char *outbuf, int bu
*p = *pict; *p = *pict;
p->pict_type = FF_I_TYPE; p->pict_type = FF_I_TYPE;
p->key_frame = 1; p->key_frame = 1;
gif_image_write_header(&outbuf_ptr, avctx->width, avctx->height, -1, (uint32_t *)pict->data[1]); gif_image_write_header(&outbuf_ptr, avctx->width, avctx->height, (uint32_t *)pict->data[1]);
gif_image_write_image(&outbuf_ptr, 0, 0, avctx->width, avctx->height, pict->data[0], pict->linesize[0], PIX_FMT_PAL8); gif_image_write_image(&outbuf_ptr, 0, 0, avctx->width, avctx->height, pict->data[0], pict->linesize[0], PIX_FMT_PAL8);
return outbuf_ptr - outbuf; return outbuf_ptr - outbuf;
} }