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288 lines
13 KiB
288 lines
13 KiB
/* |
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* GIF encoder. |
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* Copyright (c) 2000 Fabrice Bellard |
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* Copyright (c) 2002 Francois Revol |
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* Copyright (c) 2006 Baptiste Coudurier |
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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 "avcodec.h" |
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#include "bytestream.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 "bitstream.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: this was probably due to missing 'Data Sub-block Terminator' (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 for g in 00 33 66 99 cc ff; do echo -n " "; for b in 00 33 66 99 cc ff; do |
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* echo -n "{ 0x$r, 0x$g, 0x$b }, "; done; echo ""; done; 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(uint8_t **bytestream, |
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int width, int height, int loop_count, |
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uint32_t *palette) |
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{ |
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int i; |
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unsigned int v; |
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bytestream_put_buffer(bytestream, "GIF", 3); |
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bytestream_put_buffer(bytestream, "89a", 3); |
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bytestream_put_le16(bytestream, width); |
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bytestream_put_le16(bytestream, height); |
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bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */ |
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bytestream_put_byte(bytestream, 0x1f); /* background color index */ |
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bytestream_put_byte(bytestream, 0); /* aspect ratio */ |
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/* the global palette */ |
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if (!palette) { |
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bytestream_put_buffer(bytestream, (const unsigned char *)gif_clut, 216*3); |
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for(i=0;i<((256-216)*3);i++) |
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bytestream_put_byte(bytestream, 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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bytestream_put_be24(bytestream, v); |
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} |
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} |
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/* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated gif |
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see http://members.aol.com/royalef/gifabout.htm#net-extension |
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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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bytestream_put_byte(bytestream, 0x21); |
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bytestream_put_byte(bytestream, 0xff); |
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bytestream_put_byte(bytestream, 0x0b); |
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bytestream_put_buffer(bytestream, "NETSCAPE2.0", 11); // bytes 4 to 14 |
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bytestream_put_byte(bytestream, 0x03); // byte 15 |
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bytestream_put_byte(bytestream, 0x01); // byte 16 |
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bytestream_put_le16(bytestream, (uint16_t)loop_count); |
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bytestream_put_byte(bytestream, 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(uint8_t **bytestream, |
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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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bytestream_put_byte(bytestream, 0x2c); |
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bytestream_put_le16(bytestream, x1); |
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bytestream_put_le16(bytestream, y1); |
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bytestream_put_le16(bytestream, width); |
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bytestream_put_le16(bytestream, height); |
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bytestream_put_byte(bytestream, 0x00); /* flags */ |
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/* no local clut */ |
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bytestream_put_byte(bytestream, 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 byte before |
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* 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(pbBufPtr(&p) - p.buf > 0) { |
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bytestream_put_byte(bytestream, pbBufPtr(&p) - p.buf); /* byte count of the packet */ |
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bytestream_put_buffer(bytestream, p.buf, pbBufPtr(&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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bytestream_put_byte(bytestream, 0x00); /* end of image block */ |
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bytestream_put_byte(bytestream, 0x3b); |
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return 0; |
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} |
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typedef struct { |
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int64_t time, file_time; |
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uint8_t buffer[100]; /* data chunks */ |
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AVFrame picture; |
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} GIFContext; |
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static av_cold int gif_encode_init(AVCodecContext *avctx) |
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{ |
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GIFContext *s = avctx->priv_data; |
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avctx->coded_frame = &s->picture; |
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return 0; |
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} |
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/* better than nothing gif encoder */ |
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static int gif_encode_frame(AVCodecContext *avctx, unsigned char *outbuf, int buf_size, void *data) |
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{ |
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GIFContext *s = avctx->priv_data; |
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AVFrame *pict = data; |
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AVFrame *const p = (AVFrame *)&s->picture; |
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uint8_t *outbuf_ptr = outbuf; |
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*p = *pict; |
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p->pict_type = FF_I_TYPE; |
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p->key_frame = 1; |
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gif_image_write_header(&outbuf_ptr, avctx->width, avctx->height, -1, (uint32_t *)pict->data[1]); |
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gif_image_write_image(&outbuf_ptr, 0, 0, avctx->width, avctx->height, pict->data[0], pict->linesize[0], PIX_FMT_PAL8); |
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return outbuf_ptr - outbuf; |
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} |
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AVCodec gif_encoder = { |
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"gif", |
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CODEC_TYPE_VIDEO, |
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CODEC_ID_GIF, |
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sizeof(GIFContext), |
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gif_encode_init, |
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gif_encode_frame, |
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NULL, //encode_end, |
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.pix_fmts= (enum PixelFormat[]){PIX_FMT_PAL8, PIX_FMT_NONE}, |
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.long_name= NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), |
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};
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