mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
380 lines
15 KiB
380 lines
15 KiB
/* |
|
* Animated GIF muxer |
|
* Copyright (c) 2000 Fabrice Bellard |
|
* |
|
* first version by Francois Revol <revol@free.fr> |
|
* |
|
* This file is part of Libav. |
|
* |
|
* Libav 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, |
|
* 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 |
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
|
*/ |
|
|
|
/* |
|
* Features and limitations: |
|
* - currently no compression is performed, |
|
* in fact the size of the data is 9/8 the size of the image in 8bpp |
|
* - uses only a global standard palette |
|
* - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS). |
|
* |
|
* Reference documents: |
|
* http://www.goice.co.jp/member/mo/formats/gif.html |
|
* http://astronomy.swin.edu.au/pbourke/dataformats/gif/ |
|
* http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt |
|
* |
|
* this url claims to have an LZW algorithm not covered by Unisys patent: |
|
* http://www.msg.net/utility/whirlgif/gifencod.html |
|
* could help reduce the size of the files _a lot_... |
|
* some sites mentions an RLE type compression also. |
|
*/ |
|
|
|
#include "avformat.h" |
|
#include "libavutil/log.h" |
|
#include "libavutil/opt.h" |
|
|
|
/* The GIF format uses reversed order for bitstreams... */ |
|
/* at least they don't use PDP_ENDIAN :) */ |
|
#define BITSTREAM_WRITER_LE |
|
|
|
#include "libavcodec/put_bits.h" |
|
|
|
/* bitstream minipacket size */ |
|
#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 rgb_triplet { |
|
unsigned char r; |
|
unsigned char g; |
|
unsigned char b; |
|
} rgb_triplet; |
|
|
|
/* we use the standard 216 color palette */ |
|
|
|
/* this script was used to create the palette: |
|
* for r in 00 33 66 99 cc ff; do |
|
* for g in 00 33 66 99 cc ff; do |
|
* echo -n " " |
|
* for b in 00 33 66 99 cc ff; do |
|
* echo -n "{ 0x$r, 0x$g, 0x$b }, " |
|
* done |
|
* echo "" |
|
* done |
|
* done |
|
*/ |
|
|
|
static const rgb_triplet gif_clut[216] = { |
|
{ 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff }, |
|
{ 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff }, |
|
{ 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff }, |
|
{ 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff }, |
|
{ 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff }, |
|
{ 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff }, |
|
{ 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff }, |
|
{ 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff }, |
|
{ 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff }, |
|
{ 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff }, |
|
{ 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff }, |
|
{ 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff }, |
|
{ 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff }, |
|
{ 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff }, |
|
{ 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff }, |
|
{ 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff }, |
|
{ 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff }, |
|
{ 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff }, |
|
{ 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff }, |
|
{ 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff }, |
|
{ 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff }, |
|
{ 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff }, |
|
{ 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff }, |
|
{ 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff }, |
|
{ 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff }, |
|
{ 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff }, |
|
{ 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff }, |
|
{ 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff }, |
|
{ 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff }, |
|
{ 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff }, |
|
{ 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff }, |
|
{ 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff }, |
|
{ 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff }, |
|
{ 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff }, |
|
{ 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff }, |
|
{ 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff }, |
|
}; |
|
|
|
/* GIF header */ |
|
static int gif_image_write_header(AVIOContext *pb, int width, int height, |
|
int loop_count, uint32_t *palette) |
|
{ |
|
int i; |
|
unsigned int v; |
|
|
|
avio_write(pb, "GIF", 3); |
|
avio_write(pb, "89a", 3); |
|
avio_wl16(pb, width); |
|
avio_wl16(pb, height); |
|
|
|
avio_w8(pb, 0xf7); /* flags: global clut, 256 entries */ |
|
avio_w8(pb, 0x1f); /* background color index */ |
|
avio_w8(pb, 0); /* aspect ratio */ |
|
|
|
/* the global palette */ |
|
if (!palette) { |
|
avio_write(pb, (const unsigned char *)gif_clut, 216 * 3); |
|
for (i = 0; i < ((256 - 216) * 3); i++) |
|
avio_w8(pb, 0); |
|
} else { |
|
for (i = 0; i < 256; i++) { |
|
v = palette[i]; |
|
avio_w8(pb, (v >> 16) & 0xff); |
|
avio_w8(pb, (v >> 8) & 0xff); |
|
avio_w8(pb, (v) & 0xff); |
|
} |
|
} |
|
|
|
/* 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) { |
|
avio_w8(pb, 0x21); |
|
avio_w8(pb, 0xff); |
|
avio_w8(pb, 0x0b); |
|
// bytes 4 to 14 |
|
avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1); |
|
avio_w8(pb, 0x03); // byte 15 |
|
avio_w8(pb, 0x01); // byte 16 |
|
avio_wl16(pb, (uint16_t)loop_count); |
|
avio_w8(pb, 0x00); // byte 19 |
|
} |
|
#endif |
|
return 0; |
|
} |
|
|
|
/* this is maybe slow, but allows for extensions */ |
|
static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b) |
|
{ |
|
return (((r) / 47) % 6) * 6 * 6 + (((g) / 47) % 6) * 6 + (((b) / 47) % 6); |
|
} |
|
|
|
static int gif_image_write_image(AVIOContext *pb, |
|
int x1, int y1, int width, int height, |
|
const uint8_t *buf, int linesize, int pix_fmt) |
|
{ |
|
PutBitContext p; |
|
uint8_t buffer[200]; /* 100 * 9 / 8 = 113 */ |
|
int i, left, w, v; |
|
const uint8_t *ptr; |
|
/* image block */ |
|
|
|
avio_w8(pb, 0x2c); |
|
avio_wl16(pb, x1); |
|
avio_wl16(pb, y1); |
|
avio_wl16(pb, width); |
|
avio_wl16(pb, height); |
|
avio_w8(pb, 0x00); /* flags */ |
|
/* no local clut */ |
|
|
|
avio_w8(pb, 0x08); |
|
|
|
left = width * height; |
|
|
|
init_put_bits(&p, buffer, 130); |
|
|
|
/* |
|
* the thing here is the bitstream is written as little packets, with a size |
|
* byte before but it's still the same bitstream between packets (no flush !) |
|
*/ |
|
ptr = buf; |
|
w = width; |
|
while (left > 0) { |
|
put_bits(&p, 9, 0x0100); /* clear code */ |
|
|
|
for (i = (left < GIF_CHUNKS) ? left : GIF_CHUNKS; i; i--) { |
|
if (pix_fmt == AV_PIX_FMT_RGB24) { |
|
v = gif_clut_index(ptr[0], ptr[1], ptr[2]); |
|
ptr += 3; |
|
} else { |
|
v = *ptr++; |
|
} |
|
put_bits(&p, 9, v); |
|
if (--w == 0) { |
|
w = width; |
|
buf += linesize; |
|
ptr = buf; |
|
} |
|
} |
|
|
|
if (left <= GIF_CHUNKS) { |
|
put_bits(&p, 9, 0x101); /* end of stream */ |
|
flush_put_bits(&p); |
|
} |
|
if (put_bits_ptr(&p) - p.buf > 0) { |
|
avio_w8(pb, put_bits_ptr(&p) - p.buf); /* byte count of the packet */ |
|
avio_write(pb, p.buf, put_bits_ptr(&p) - p.buf); /* the actual buffer */ |
|
p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */ |
|
} |
|
left -= GIF_CHUNKS; |
|
} |
|
avio_w8(pb, 0x00); /* end of image block */ |
|
|
|
return 0; |
|
} |
|
|
|
typedef struct GIFContext { |
|
AVClass *class; /** Class for private options. */ |
|
int64_t time, file_time; |
|
uint8_t buffer[100]; /* data chunks */ |
|
int loop; |
|
} GIFContext; |
|
|
|
static int gif_write_header(AVFormatContext *s) |
|
{ |
|
GIFContext *gif = s->priv_data; |
|
AVIOContext *pb = s->pb; |
|
AVCodecContext *enc, *video_enc; |
|
int i, width, height /*, rate*/; |
|
|
|
/* XXX: do we reject audio streams or just ignore them ? |
|
* if (s->nb_streams > 1) |
|
* return -1; |
|
*/ |
|
gif->time = 0; |
|
gif->file_time = 0; |
|
|
|
video_enc = NULL; |
|
for (i = 0; i < s->nb_streams; i++) { |
|
enc = s->streams[i]->codec; |
|
if (enc->codec_type != AVMEDIA_TYPE_AUDIO) |
|
video_enc = enc; |
|
} |
|
|
|
if (!video_enc) { |
|
av_free(gif); |
|
return -1; |
|
} else { |
|
width = video_enc->width; |
|
height = video_enc->height; |
|
// rate = video_enc->time_base.den; |
|
} |
|
|
|
if (video_enc->pix_fmt != AV_PIX_FMT_RGB24) { |
|
av_log(s, AV_LOG_ERROR, |
|
"ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.\n"); |
|
return AVERROR(EIO); |
|
} |
|
|
|
gif_image_write_header(pb, width, height, gif->loop, NULL); |
|
|
|
avio_flush(s->pb); |
|
return 0; |
|
} |
|
|
|
static int gif_write_video(AVFormatContext *s, AVCodecContext *enc, |
|
const uint8_t *buf, int size) |
|
{ |
|
AVIOContext *pb = s->pb; |
|
int jiffies; |
|
|
|
/* graphic control extension block */ |
|
avio_w8(pb, 0x21); |
|
avio_w8(pb, 0xf9); |
|
avio_w8(pb, 0x04); /* block size */ |
|
avio_w8(pb, 0x04); /* flags */ |
|
|
|
/* 1 jiffy is 1/70 s */ |
|
/* the delay_time field indicates the number of jiffies - 1 */ |
|
/* XXX: should use delay, in order to be more accurate */ |
|
/* instead of using the same rounded value each time */ |
|
/* XXX: don't even remember if I really use it for now */ |
|
jiffies = (70 * enc->time_base.num / enc->time_base.den) - 1; |
|
|
|
avio_wl16(pb, jiffies); |
|
|
|
avio_w8(pb, 0x1f); /* transparent color index */ |
|
avio_w8(pb, 0x00); |
|
|
|
gif_image_write_image(pb, 0, 0, enc->width, enc->height, |
|
buf, enc->width * 3, AV_PIX_FMT_RGB24); |
|
|
|
return 0; |
|
} |
|
|
|
static int gif_write_packet(AVFormatContext *s, AVPacket *pkt) |
|
{ |
|
AVCodecContext *codec = s->streams[pkt->stream_index]->codec; |
|
if (codec->codec_type == AVMEDIA_TYPE_AUDIO) |
|
return 0; /* just ignore audio */ |
|
else |
|
return gif_write_video(s, codec, pkt->data, pkt->size); |
|
} |
|
|
|
static int gif_write_trailer(AVFormatContext *s) |
|
{ |
|
AVIOContext *pb = s->pb; |
|
|
|
avio_w8(pb, 0x3b); |
|
|
|
return 0; |
|
} |
|
|
|
#define OFFSET(x) offsetof(GIFContext, x) |
|
#define ENC AV_OPT_FLAG_ENCODING_PARAM |
|
static const AVOption options[] = { |
|
{ "loop", "Number of times to loop the output.", OFFSET(loop), |
|
AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 65535, ENC }, |
|
{ NULL }, |
|
}; |
|
|
|
static const AVClass gif_muxer_class = { |
|
.class_name = "GIF muxer", |
|
.item_name = av_default_item_name, |
|
.version = LIBAVUTIL_VERSION_INT, |
|
.option = options, |
|
}; |
|
|
|
AVOutputFormat ff_gif_muxer = { |
|
.name = "gif", |
|
.long_name = NULL_IF_CONFIG_SMALL("GIF Animation"), |
|
.mime_type = "image/gif", |
|
.extensions = "gif", |
|
.priv_data_size = sizeof(GIFContext), |
|
.audio_codec = AV_CODEC_ID_NONE, |
|
.video_codec = AV_CODEC_ID_RAWVIDEO, |
|
.write_header = gif_write_header, |
|
.write_packet = gif_write_packet, |
|
.write_trailer = gif_write_trailer, |
|
.priv_class = &gif_muxer_class, |
|
};
|
|
|