/* * 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 { 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 { 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, };