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381 lines
15 KiB
381 lines
15 KiB
/* |
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* Animated GIF muxer |
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* Copyright (c) 2000 Fabrice Bellard |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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|
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/* |
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* First version by Francois Revol revol@free.fr |
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* |
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* Features and limitations: |
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* - currently no compression is performed, |
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* in fact the size of the data is 9/8 the size of the image in 8bpp |
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* - uses only a global standard palette |
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* - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS). |
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* |
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* Reference documents: |
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* http://www.goice.co.jp/member/mo/formats/gif.html |
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* http://astronomy.swin.edu.au/pbourke/dataformats/gif/ |
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* http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt |
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* |
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* this url claims to have an LZW algorithm not covered by Unisys patent: |
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* http://www.msg.net/utility/whirlgif/gifencod.html |
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* could help reduce the size of the files _a lot_... |
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* some sites mentions an RLE type compression also. |
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*/ |
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#include "avformat.h" |
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#include "libavutil/log.h" |
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#include "libavutil/opt.h" |
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/* The GIF format uses reversed order for bitstreams... */ |
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/* at least they don't use PDP_ENDIAN :) */ |
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#define BITSTREAM_WRITER_LE |
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#include "libavcodec/put_bits.h" |
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/* bitstream minipacket size */ |
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#define GIF_CHUNKS 100 |
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/* slows down the decoding (and some browsers don't like it) */ |
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/* update on the 'some browsers don't like it issue from above: |
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* this was probably due to missing 'Data Sub-block Terminator' |
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* (byte 19) in the app_header */ |
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#define GIF_ADD_APP_HEADER // required to enable looping of animated gif |
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typedef struct { |
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unsigned char r; |
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unsigned char g; |
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unsigned char b; |
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} rgb_triplet; |
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/* we use the standard 216 color palette */ |
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/* this script was used to create the palette: |
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* for r in 00 33 66 99 cc ff; do |
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* for g in 00 33 66 99 cc ff; do |
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* echo -n " " |
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* for b in 00 33 66 99 cc ff; do |
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* echo -n "{ 0x$r, 0x$g, 0x$b }, " |
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* done |
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* echo "" |
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* done |
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* done |
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*/ |
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static const rgb_triplet gif_clut[216] = { |
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{ 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff }, |
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{ 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff }, |
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{ 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff }, |
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{ 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff }, |
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{ 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff }, |
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{ 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff }, |
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{ 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff }, |
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{ 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff }, |
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{ 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff }, |
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{ 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff }, |
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{ 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff }, |
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{ 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff }, |
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{ 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff }, |
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{ 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff }, |
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{ 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff }, |
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{ 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff }, |
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{ 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff }, |
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{ 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff }, |
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{ 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff }, |
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{ 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff }, |
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{ 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff }, |
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{ 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff }, |
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{ 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff }, |
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{ 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff }, |
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{ 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff }, |
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{ 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff }, |
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{ 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff }, |
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{ 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff }, |
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{ 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff }, |
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{ 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff }, |
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{ 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff }, |
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{ 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff }, |
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{ 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff }, |
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{ 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff }, |
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{ 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff }, |
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{ 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff }, |
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}; |
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/* GIF header */ |
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static int gif_image_write_header(AVIOContext *pb, int width, int height, |
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int loop_count, uint32_t *palette) |
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{ |
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int i; |
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unsigned int v; |
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avio_write(pb, "GIF", 3); |
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avio_write(pb, "89a", 3); |
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avio_wl16(pb, width); |
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avio_wl16(pb, height); |
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avio_w8(pb, 0xf7); /* flags: global clut, 256 entries */ |
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avio_w8(pb, 0x1f); /* background color index */ |
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avio_w8(pb, 0); /* aspect ratio */ |
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/* the global palette */ |
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if (!palette) { |
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avio_write(pb, (const unsigned char *)gif_clut, 216 * 3); |
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for (i = 0; i < ((256 - 216) * 3); i++) |
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avio_w8(pb, 0); |
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} else { |
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for (i = 0; i < 256; i++) { |
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v = palette[i]; |
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avio_w8(pb, (v >> 16) & 0xff); |
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avio_w8(pb, (v >> 8) & 0xff); |
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avio_w8(pb, (v) & 0xff); |
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} |
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} |
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/* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated |
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* GIF, see http://members.aol.com/royalef/gifabout.htm#net-extension |
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* |
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* byte 1 : 33 (hex 0x21) GIF Extension code |
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* byte 2 : 255 (hex 0xFF) Application Extension Label |
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* byte 3 : 11 (hex (0x0B) Length of Application Block |
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* (eleven bytes of data to follow) |
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* bytes 4 to 11 : "NETSCAPE" |
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* bytes 12 to 14 : "2.0" |
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* byte 15 : 3 (hex 0x03) Length of Data Sub-Block |
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* (three bytes of data to follow) |
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* byte 16 : 1 (hex 0x01) |
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* bytes 17 to 18 : 0 to 65535, an unsigned integer in |
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* lo-hi byte format. This indicate the |
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* number of iterations the loop should |
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* be executed. |
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* bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator |
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*/ |
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/* application extension header */ |
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#ifdef GIF_ADD_APP_HEADER |
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if (loop_count >= 0 && loop_count <= 65535) { |
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avio_w8(pb, 0x21); |
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avio_w8(pb, 0xff); |
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avio_w8(pb, 0x0b); |
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// bytes 4 to 14 |
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avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1); |
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avio_w8(pb, 0x03); // byte 15 |
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avio_w8(pb, 0x01); // byte 16 |
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avio_wl16(pb, (uint16_t)loop_count); |
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avio_w8(pb, 0x00); // byte 19 |
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} |
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#endif |
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return 0; |
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} |
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/* this is maybe slow, but allows for extensions */ |
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static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b) |
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{ |
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return (((r) / 47) % 6) * 6 * 6 + (((g) / 47) % 6) * 6 + (((b) / 47) % 6); |
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} |
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static int gif_image_write_image(AVIOContext *pb, |
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int x1, int y1, int width, int height, |
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const uint8_t *buf, int linesize, int pix_fmt) |
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{ |
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PutBitContext p; |
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uint8_t buffer[200]; /* 100 * 9 / 8 = 113 */ |
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int i, left, w, v; |
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const uint8_t *ptr; |
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/* image block */ |
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avio_w8(pb, 0x2c); |
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avio_wl16(pb, x1); |
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avio_wl16(pb, y1); |
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avio_wl16(pb, width); |
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avio_wl16(pb, height); |
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avio_w8(pb, 0x00); /* flags */ |
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/* no local clut */ |
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avio_w8(pb, 0x08); |
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left = width * height; |
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init_put_bits(&p, buffer, 130); |
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/* |
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* the thing here is the bitstream is written as little packets, with a size |
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* byte before but it's still the same bitstream between packets (no flush !) |
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*/ |
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ptr = buf; |
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w = width; |
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while (left > 0) { |
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put_bits(&p, 9, 0x0100); /* clear code */ |
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for (i = (left < GIF_CHUNKS) ? left : GIF_CHUNKS; i; i--) { |
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if (pix_fmt == PIX_FMT_RGB24) { |
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v = gif_clut_index(ptr[0], ptr[1], ptr[2]); |
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ptr += 3; |
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} else { |
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v = *ptr++; |
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} |
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put_bits(&p, 9, v); |
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if (--w == 0) { |
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w = width; |
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buf += linesize; |
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ptr = buf; |
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} |
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} |
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if (left <= GIF_CHUNKS) { |
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put_bits(&p, 9, 0x101); /* end of stream */ |
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flush_put_bits(&p); |
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} |
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if (put_bits_ptr(&p) - p.buf > 0) { |
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avio_w8(pb, put_bits_ptr(&p) - p.buf); /* byte count of the packet */ |
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avio_write(pb, p.buf, put_bits_ptr(&p) - p.buf); /* the actual buffer */ |
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p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */ |
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} |
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left -= GIF_CHUNKS; |
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} |
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avio_w8(pb, 0x00); /* end of image block */ |
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return 0; |
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} |
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typedef struct { |
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AVClass *class; /** Class for private options. */ |
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int64_t time, file_time; |
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uint8_t buffer[100]; /* data chunks */ |
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int loop; |
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} GIFContext; |
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static int gif_write_header(AVFormatContext *s) |
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{ |
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GIFContext *gif = s->priv_data; |
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AVIOContext *pb = s->pb; |
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AVCodecContext *enc, *video_enc; |
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int i, width, height /*, rate*/; |
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/* XXX: do we reject audio streams or just ignore them ? |
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* if (s->nb_streams > 1) |
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* return -1; |
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*/ |
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gif->time = 0; |
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gif->file_time = 0; |
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video_enc = NULL; |
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for (i = 0; i < s->nb_streams; i++) { |
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enc = s->streams[i]->codec; |
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if (enc->codec_type != AVMEDIA_TYPE_AUDIO) |
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video_enc = enc; |
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} |
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if (!video_enc) { |
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av_free(gif); |
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return -1; |
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} else { |
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width = video_enc->width; |
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height = video_enc->height; |
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// rate = video_enc->time_base.den; |
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} |
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if (video_enc->pix_fmt != PIX_FMT_RGB24) { |
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av_log(s, AV_LOG_ERROR, |
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"ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.\n"); |
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return AVERROR(EIO); |
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} |
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gif_image_write_header(pb, width, height, gif->loop, NULL); |
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avio_flush(s->pb); |
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return 0; |
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} |
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static int gif_write_video(AVFormatContext *s, AVCodecContext *enc, |
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const uint8_t *buf, int size) |
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{ |
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AVIOContext *pb = s->pb; |
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int jiffies; |
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/* graphic control extension block */ |
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avio_w8(pb, 0x21); |
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avio_w8(pb, 0xf9); |
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avio_w8(pb, 0x04); /* block size */ |
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avio_w8(pb, 0x04); /* flags */ |
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/* 1 jiffy is 1/70 s */ |
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/* the delay_time field indicates the number of jiffies - 1 */ |
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/* XXX: should use delay, in order to be more accurate */ |
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/* instead of using the same rounded value each time */ |
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/* XXX: don't even remember if I really use it for now */ |
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jiffies = (70 * enc->time_base.num / enc->time_base.den) - 1; |
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avio_wl16(pb, jiffies); |
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avio_w8(pb, 0x1f); /* transparent color index */ |
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avio_w8(pb, 0x00); |
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gif_image_write_image(pb, 0, 0, enc->width, enc->height, |
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buf, enc->width * 3, PIX_FMT_RGB24); |
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avio_flush(s->pb); |
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return 0; |
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} |
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static int gif_write_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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AVCodecContext *codec = s->streams[pkt->stream_index]->codec; |
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if (codec->codec_type == AVMEDIA_TYPE_AUDIO) |
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return 0; /* just ignore audio */ |
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else |
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return gif_write_video(s, codec, pkt->data, pkt->size); |
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} |
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static int gif_write_trailer(AVFormatContext *s) |
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{ |
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AVIOContext *pb = s->pb; |
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avio_w8(pb, 0x3b); |
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avio_flush(s->pb); |
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return 0; |
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} |
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#define OFFSET(x) offsetof(GIFContext, x) |
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#define ENC AV_OPT_FLAG_ENCODING_PARAM |
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static const AVOption options[] = { |
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{ "loop", "Number of times to loop the output.", OFFSET(loop), |
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AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 65535, ENC }, |
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{ NULL }, |
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}; |
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static const AVClass gif_muxer_class = { |
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.class_name = "GIF muxer", |
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.item_name = av_default_item_name, |
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.version = LIBAVUTIL_VERSION_INT, |
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.option = options, |
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}; |
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AVOutputFormat ff_gif_muxer = { |
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.name = "gif", |
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.long_name = NULL_IF_CONFIG_SMALL("GIF Animation"), |
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.mime_type = "image/gif", |
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.extensions = "gif", |
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.priv_data_size = sizeof(GIFContext), |
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.audio_codec = AV_CODEC_ID_NONE, |
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.video_codec = AV_CODEC_ID_RAWVIDEO, |
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.write_header = gif_write_header, |
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.write_packet = gif_write_packet, |
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.write_trailer = gif_write_trailer, |
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.priv_class = &gif_muxer_class, |
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};
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