diff options
Diffstat (limited to 'ffmpeg/libavformat/gif.c')
| -rw-r--r-- | ffmpeg/libavformat/gif.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/ffmpeg/libavformat/gif.c b/ffmpeg/libavformat/gif.c new file mode 100644 index 0000000..31b0101 --- /dev/null +++ b/ffmpeg/libavformat/gif.c @@ -0,0 +1,381 @@ +/* + * Animated GIF muxer + * Copyright (c) 2000 Fabrice Bellard + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; 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 "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); + + avio_flush(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 == 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, +}; |