/* * Animated GIF encoder * Copyright (c) 2000 Fabrice Bellard. * * This library 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 of the License, or (at your option) any later version. * * This library 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 this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /* * First version by Francois Revol revol@free.fr * * 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 "bitstream.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 { 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 }, }; /* The GIF format uses reversed order for bitstreams... */ /* at least they don't use PDP_ENDIAN :) */ /* so we 'extend' PutBitContext. hmmm, OOP :) */ /* seems this thing changed slightly since I wrote it... */ #ifdef ALT_BITSTREAM_WRITER # error no ALT_BITSTREAM_WRITER support for now #endif static void gif_put_bits_rev(PutBitContext *s, int n, unsigned int value) { unsigned int bit_buf; int bit_cnt; // printf("put_bits=%d %x\n", n, value); assert(n == 32 || value < (1U << n)); bit_buf = s->bit_buf; bit_cnt = 32 - s->bit_left; /* XXX:lazyness... was = s->bit_cnt; */ // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); /* XXX: optimize */ if (n < (32-bit_cnt)) { bit_buf |= value << (bit_cnt); bit_cnt+=n; } else { bit_buf |= value << (bit_cnt); *s->buf_ptr = bit_buf & 0xff; s->buf_ptr[1] = (bit_buf >> 8) & 0xff; s->buf_ptr[2] = (bit_buf >> 16) & 0xff; s->buf_ptr[3] = (bit_buf >> 24) & 0xff; //printf("bitbuf = %08x\n", bit_buf); s->buf_ptr+=4; if (s->buf_ptr >= s->buf_end) puts("bit buffer overflow !!"); // should never happen ! who got rid of the callback ??? // flush_buffer_rev(s); bit_cnt=bit_cnt + n - 32; if (bit_cnt == 0) { bit_buf = 0; } else { bit_buf = value >> (n - bit_cnt); } } s->bit_buf = bit_buf; s->bit_left = 32 - bit_cnt; } /* pad the end of the output stream with zeros */ static void gif_flush_put_bits_rev(PutBitContext *s) { while (s->bit_left < 32) { /* XXX: should test end of buffer */ *s->buf_ptr++=s->bit_buf & 0xff; s->bit_buf>>=8; s->bit_left+=8; } // flush_buffer_rev(s); s->bit_left=32; s->bit_buf=0; } /* !RevPutBitContext */ /* GIF header */ static int gif_image_write_header(ByteIOContext *pb, int width, int height, int loop_count, uint32_t *palette) { int i; unsigned int v; put_tag(pb, "GIF"); put_tag(pb, "89a"); put_le16(pb, width); put_le16(pb, height); put_byte(pb, 0xf7); /* flags: global clut, 256 entries */ put_byte(pb, 0x1f); /* background color index */ put_byte(pb, 0); /* aspect ratio */ /* the global palette */ if (!palette) { put_buffer(pb, (const unsigned char *)gif_clut, 216*3); for(i=0;i<((256-216)*3);i++) put_byte(pb, 0); } else { for(i=0;i<256;i++) { v = palette[i]; put_byte(pb, (v >> 16) & 0xff); put_byte(pb, (v >> 8) & 0xff); put_byte(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) { put_byte(pb, 0x21); put_byte(pb, 0xff); put_byte(pb, 0x0b); 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; } /* 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(ByteIOContext *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 */ put_byte(pb, 0x2c); put_le16(pb, x1); put_le16(pb, y1); put_le16(pb, width); put_le16(pb, height); put_byte(pb, 0x00); /* flags */ /* no local clut */ put_byte(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) { gif_put_bits_rev(&p, 9, 0x0100); /* clear code */ for(i=(left<GIF_CHUNKS)?left:GIF_CHUNKS;i;i--) { if (pix_fmt == PIX_FMT_RGB24) { v = gif_clut_index(ptr[0], ptr[1], ptr[2]); ptr+=3; } else { v = *ptr++; } gif_put_bits_rev(&p, 9, v); if (--w == 0) { w = width; buf += linesize; ptr = buf; } } if(left<=GIF_CHUNKS) { gif_put_bits_rev(&p, 9, 0x101); /* end of stream */ gif_flush_put_bits_rev(&p); } if(pbBufPtr(&p) - p.buf > 0) { put_byte(pb, pbBufPtr(&p) - p.buf); /* byte count of the packet */ put_buffer(pb, p.buf, pbBufPtr(&p) - p.buf); /* the actual buffer */ p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */ } left-=GIF_CHUNKS; } put_byte(pb, 0x00); /* end of image block */ return 0; } typedef struct { int64_t time, file_time; uint8_t buffer[100]; /* data chunks */ } GIFContext; static int gif_write_header(AVFormatContext *s) { GIFContext *gif = s->priv_data; ByteIOContext *pb = &s->pb; AVCodecContext *enc, *video_enc; int i, width, height, loop_count /*, 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 != CODEC_TYPE_AUDIO) video_enc = enc; } if (!video_enc) { av_free(gif); return -1; } else { width = video_enc->width; height = video_enc->height; loop_count = s->loop_output; // rate = video_enc->time_base.den; } if (video_enc->pix_fmt != PIX_FMT_RGB24) { av_log(s, AV_LOG_ERROR, "ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.\n"); return AVERROR_IO; } gif_image_write_header(pb, width, height, loop_count, NULL); put_flush_packet(&s->pb); return 0; } static int gif_write_video(AVFormatContext *s, AVCodecContext *enc, const uint8_t *buf, int size) { ByteIOContext *pb = &s->pb; GIFContext *gif = s->priv_data; int jiffies; int64_t delay; /* graphic control extension block */ put_byte(pb, 0x21); put_byte(pb, 0xf9); put_byte(pb, 0x04); /* block size */ put_byte(pb, 0x04); /* flags */ /* 1 jiffy is 1/70 s */ /* the delay_time field indicates the number of jiffies - 1 */ delay = gif->file_time - gif->time; /* 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; put_le16(pb, jiffies); put_byte(pb, 0x1f); /* transparent color index */ put_byte(pb, 0x00); gif_image_write_image(pb, 0, 0, enc->width, enc->height, buf, enc->width * 3, PIX_FMT_RGB24); put_flush_packet(&s->pb); return 0; } static int gif_write_packet(AVFormatContext *s, AVPacket *pkt) { AVCodecContext *codec = s->streams[pkt->stream_index]->codec; if (codec->codec_type == CODEC_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) { ByteIOContext *pb = &s->pb; put_byte(pb, 0x3b); put_flush_packet(&s->pb); return 0; } /* better than nothing gif image writer */ int gif_write(ByteIOContext *pb, AVImageInfo *info) { 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], PIX_FMT_PAL8); put_byte(pb, 0x3b); put_flush_packet(pb); return 0; } AVOutputFormat gif_muxer = { "gif", "GIF Animation", "image/gif", "gif", sizeof(GIFContext), CODEC_ID_NONE, CODEC_ID_RAWVIDEO, gif_write_header, gif_write_packet, gif_write_trailer, };