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Animated GIF looping patch by (Todd Kirby // ffmpeg.php gmail com)

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Originally committed as revision 4383 to svn://svn.ffmpeg.org/ffmpeg/trunk
pull/126/head
Todd Kirby 20 years ago committed by Michael Niedermayer
parent bb628dae44
commit 8108551a5c
4 changed files with 48 additions and 13 deletions
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  1. 3
      doc/ffmpeg-doc.texi
  2. 3
      ffmpeg.c
  3. 8
      libavformat/avformat.h
  4. 47
      libavformat/gif.c

3
doc/ffmpeg-doc.texi
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@ -498,6 +498,9 @@ read input at native frame rate. Mainly used to simulate a grab device.
@item -loop
loop over the input stream. Currently it works only for image
streams. This option is used for ffserver automatic testing.
@item -loop_output number_of_times
Repeatedly loop output for formats that support looping such as animated gif
(Zero will loop the output infinitely)
@end table
@node FFmpeg formula evaluator

3
ffmpeg.c
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@ -209,6 +209,7 @@ static int frame_skip_factor= 0;
static int frame_skip_exp= 0;
static int frame_skip_cmp= FF_CMP_DCTMAX;
extern int loop_input; /* currently a hack */
static int loop_output = AVFMT_NOOUTPUTLOOP;
static int gray_only = 0;
static int gop_size = 12;
@ -3689,6 +3690,7 @@ static void opt_output_file(const char *filename)
oc->mux_rate= mux_rate;
oc->preload= (int)(mux_preload*AV_TIME_BASE);
oc->max_delay= (int)(mux_max_delay*AV_TIME_BASE);
oc->loop_output = loop_output;
/* reset some options */
file_oformat = NULL;
@ -4177,6 +4179,7 @@ const OptionDef options[] = {
{ "bitexact", OPT_EXPERT, {(void*)opt_bitexact}, "only use bit exact algorithms (for codec testing)" },
{ "re", OPT_BOOL | OPT_EXPERT, {(void*)&rate_emu}, "read input at native frame rate", "" },
{ "loop", OPT_BOOL | OPT_EXPERT, {(void*)&loop_input}, "loop (current only works with images)" },
{ "loop_output", HAS_ARG | OPT_INT | OPT_EXPERT, {(void*)&loop_output}, "number of times to loop output in formats that support looping (0 loops forever)", "" },
{ "v", HAS_ARG, {(void*)opt_verbose}, "control amount of logging", "verbose" },
{ "target", HAS_ARG, {(void*)opt_target}, "specify target file type (\"vcd\", \"svcd\", \"dvd\", \"dv\", \"pal-vcd\", \"ntsc-svcd\", ...)", "type" },
{ "threads", HAS_ARG | OPT_EXPERT, {(void*)opt_thread_count}, "thread count", "count" },

8
libavformat/avformat.h
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@ -5,7 +5,7 @@
extern "C" {
#endif
#define LIBAVFORMAT_BUILD 4626
#define LIBAVFORMAT_BUILD 4627
#define LIBAVFORMAT_VERSION_INT FFMPEG_VERSION_INT
#define LIBAVFORMAT_VERSION FFMPEG_VERSION
@ -327,6 +327,12 @@ typedef struct AVFormatContext {
int packet_size;
int preload;
int max_delay;
#define AVFMT_NOOUTPUTLOOP -1
#define AVFMT_INFINITEOUTPUTLOOP 0
/* number of times to loop output in formats that support it */
int loop_output;
} AVFormatContext;
typedef struct AVPacketList {

47
libavformat/gif.c
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@ -43,8 +43,9 @@
/* bitstream minipacket size */
#define GIF_CHUNKS 100
/* slows down the decoding (and some browsers doesn't like it) */
/* #define GIF_ADD_APP_HEADER */
/* 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 {
unsigned char r;
@ -169,7 +170,8 @@ static void gif_flush_put_bits_rev(PutBitContext *s)
/* GIF header */
static int gif_image_write_header(ByteIOContext *pb,
int width, int height, uint32_t *palette)
int width, int height, int loop_count,
uint32_t *palette)
{
int i;
unsigned int v;
@ -197,17 +199,37 @@ static int gif_image_write_header(ByteIOContext *pb,
}
}
/* 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 */
/* XXX: not really sure what to put in here... */
#ifdef GIF_ADD_APP_HEADER
if (loop_count >= 0 && loop_count <= 65535) {
put_byte(pb, 0x21);
put_byte(pb, 0xff);
put_byte(pb, 0x0b);
put_tag(pb, "NETSCAPE2.0");
put_byte(pb, 0x03);
put_byte(pb, 0x01);
put_byte(pb, 0x00);
put_byte(pb, 0x00);
put_tag(pb, "NETSCAPE2.0"); // bytes 4 to 14
put_byte(pb, 0x03); // byte 15
put_byte(pb, 0x01); // byte 16
put_le16(pb, (uint16_t)loop_count);
put_byte(pb, 0x00); // byte 19
}
#endif
return 0;
}
@ -294,7 +316,7 @@ static int gif_write_header(AVFormatContext *s)
GIFContext *gif = s->priv_data;
ByteIOContext *pb = &s->pb;
AVCodecContext *enc, *video_enc;
int i, width, height/*, rate*/;
int i, width, height, loop_count /*, rate*/;
/* XXX: do we reject audio streams or just ignore them ?
if(s->nb_streams > 1)
@ -316,13 +338,14 @@ static int gif_write_header(AVFormatContext *s)
} else {
width = video_enc->width;
height = video_enc->height;
loop_count = s->loop_output;
// rate = video_enc->time_base.den;
}
/* XXX: is it allowed ? seems to work so far... */
video_enc->pix_fmt = PIX_FMT_RGB24;
gif_image_write_header(pb, width, height, NULL);
gif_image_write_header(pb, width, height, loop_count, NULL);
put_flush_packet(&s->pb);
return 0;
@ -384,7 +407,7 @@ static int gif_write_trailer(AVFormatContext *s)
/* better than nothing gif image writer */
int gif_write(ByteIOContext *pb, AVImageInfo *info)
{
gif_image_write_header(pb, info->width, info->height,
gif_image_write_header(pb, info->width, info->height, AVFMT_NOOUTPUTLOOP,
(uint32_t *)info->pict.data[1]);
gif_image_write_image(pb, 0, 0, info->width, info->height,
info->pict.data[0], info->pict.linesize[0],

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