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403 lines
14 KiB
403 lines
14 KiB
/* |
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* Animated GIF encoder |
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* Copyright (c) 2000 Gerard Lantau. |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program 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 |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, 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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|
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/* bitstream minipacket size */ |
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#define GIF_CHUNKS 100 |
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|
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/* slows down the decoding (and some browsers doesn't like it) */ |
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/* #define GIF_ADD_APP_HEADER */ |
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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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|
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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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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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/* The GIF format uses reversed order for bitstreams... */ |
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/* at least they don't use PDP_ENDIAN :) */ |
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/* so we 'extend' PutBitContext. hmmm, OOP :) */ |
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/* seems this thing changed slightly since I wrote it... */ |
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#ifdef ALT_BITSTREAM_WRITER |
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# error no ALT_BITSTREAM_WRITER support for now |
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#endif |
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void init_put_bits_rev(PutBitContext *s, |
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UINT8 *buffer, int buffer_size, |
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void *opaque, |
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void (*write_data)(void *, UINT8 *, int)) |
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{ |
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init_put_bits(s, buffer, buffer_size, opaque, write_data); |
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} |
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void put_bits_rev(PutBitContext *s, int n, unsigned int value) |
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{ |
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unsigned int bit_buf; |
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int bit_cnt; |
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#ifdef STATS |
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st_out_bit_counts[st_current_index] += n; |
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#endif |
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// printf("put_bits=%d %x\n", n, value); |
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assert(n == 32 || value < (1U << n)); |
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bit_buf = s->bit_buf; |
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bit_cnt = 32 - s->bit_left; /* XXX:lazyness... was = s->bit_cnt; */ |
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// printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); |
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/* XXX: optimize */ |
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if (n < (32-bit_cnt)) { |
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bit_buf |= value << (bit_cnt); |
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bit_cnt+=n; |
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} else { |
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bit_buf |= value << (bit_cnt); |
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*s->buf_ptr = bit_buf & 0xff; |
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s->buf_ptr[1] = (bit_buf >> 8) & 0xff; |
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s->buf_ptr[2] = (bit_buf >> 16) & 0xff; |
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s->buf_ptr[3] = (bit_buf >> 24) & 0xff; |
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//printf("bitbuf = %08x\n", bit_buf); |
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s->buf_ptr+=4; |
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if (s->buf_ptr >= s->buf_end) |
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puts("bit buffer overflow !!"); // should never happen ! who got rid of the callback ??? |
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// flush_buffer_rev(s); |
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bit_cnt=bit_cnt + n - 32; |
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if (bit_cnt == 0) { |
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bit_buf = 0; |
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} else { |
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bit_buf = value >> (n - bit_cnt); |
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} |
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} |
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s->bit_buf = bit_buf; |
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s->bit_left = 32 - bit_cnt; |
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} |
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/* return the number of bits output */ |
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INT64 get_bit_count_rev(PutBitContext *s) |
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{ |
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return get_bit_count(s); |
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} |
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void align_put_bits_rev(PutBitContext *s) |
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{ |
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align_put_bits(s); |
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} |
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/* pad the end of the output stream with zeros */ |
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void flush_put_bits_rev(PutBitContext *s) |
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{ |
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while (s->bit_left < 32) { |
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/* XXX: should test end of buffer */ |
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*s->buf_ptr++=s->bit_buf & 0xff; |
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s->bit_buf>>=8; |
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s->bit_left+=8; |
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} |
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// flush_buffer_rev(s); |
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s->bit_left=32; |
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s->bit_buf=0; |
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} |
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/* !RevPutBitContext */ |
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typedef struct { |
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UINT8 buffer[100]; /* data chunks */ |
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INT64 time, file_time; |
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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; |
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ByteIOContext *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 = malloc(sizeof(GIFContext)); |
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if (!gif) |
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return -1; |
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s->priv_data = gif; |
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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 != CODEC_TYPE_AUDIO) |
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video_enc = enc; |
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} |
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if (!video_enc) { |
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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->frame_rate; |
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} |
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/* XXX: is it allowed ? seems to work so far... */ |
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video_enc->pix_fmt = PIX_FMT_RGB24; |
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/* GIF header */ |
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put_tag(pb, "GIF"); |
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put_tag(pb, "89a"); |
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put_le16(pb, width); |
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put_le16(pb, height); |
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put_byte(pb, 0xf7); /* flags: global clut, 256 entries */ |
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put_byte(pb, 0x1f); /* background color index */ |
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put_byte(pb, 0); /* aspect ratio */ |
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/* the global palette */ |
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put_buffer(pb, (unsigned char *)gif_clut, 216*3); |
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for(i=0;i<((256-216)*3);i++) |
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put_byte(pb, 0); |
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/* application extension header */ |
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/* XXX: not really sure what to put in here... */ |
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#ifdef GIF_ADD_APP_HEADER |
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put_byte(pb, 0x21); |
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put_byte(pb, 0xff); |
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put_byte(pb, 0x0b); |
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put_tag(pb, "NETSCAPE2.0"); |
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put_byte(pb, 0x03); |
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put_byte(pb, 0x01); |
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put_byte(pb, 0x00); |
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put_byte(pb, 0x00); |
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#endif |
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put_flush_packet(&s->pb); |
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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(rgb_triplet *clut, UINT8 r, UINT8 g, UINT8 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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/* chunk writer callback */ |
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/* !!! XXX:deprecated |
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static void gif_put_chunk(void *pbctx, UINT8 *buffer, int count) |
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{ |
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ByteIOContext *pb = (ByteIOContext *)pbctx; |
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put_byte(pb, (UINT8)count); |
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put_buffer(pb, buffer, count); |
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} |
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*/ |
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static int gif_write_video(AVFormatContext *s, |
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AVCodecContext *enc, UINT8 *buf, int size) |
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{ |
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ByteIOContext *pb = &s->pb; |
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GIFContext *gif = s->priv_data; |
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int i, left, jiffies; |
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INT64 delay; |
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PutBitContext p; |
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UINT8 buffer[200]; /* 100 * 9 / 8 = 113 */ |
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/* graphic control extension block */ |
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put_byte(pb, 0x21); |
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put_byte(pb, 0xf9); |
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put_byte(pb, 0x04); /* block size */ |
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put_byte(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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delay = gif->file_time - gif->time; |
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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*FRAME_RATE_BASE/enc->frame_rate) - 1; |
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put_le16(pb, jiffies); |
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put_byte(pb, 0x1f); /* transparent color index */ |
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put_byte(pb, 0x00); |
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/* image block */ |
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put_byte(pb, 0x2c); |
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put_le16(pb, 0); |
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put_le16(pb, 0); |
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put_le16(pb, enc->width); |
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put_le16(pb, enc->height); |
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put_byte(pb, 0x00); /* flags */ |
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/* no local clut */ |
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put_byte(pb, 0x08); |
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left=size/3; |
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/* XXX:deprecated */ |
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/*init_put_bits_rev(&p, buffer, sizeof(buf), (void *)pb, gif_put_chunk); *//* mmm found a but in my code: s/sizeof(buf)/150/ */ |
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init_put_bits_rev(&p, buffer, 130, NULL, NULL); |
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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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while(left>0) { |
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put_bits_rev(&p, 9, 0x0100); /* clear code */ |
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for(i=0;i<GIF_CHUNKS;i++) { |
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put_bits_rev(&p, 9, gif_clut_index(NULL, *buf, buf[1], buf[2])); |
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buf+=3; |
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} |
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if(left<=GIF_CHUNKS) { |
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put_bits_rev(&p, 9, 0x101); /* end of stream */ |
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flush_put_bits_rev(&p); |
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} |
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if(pbBufPtr(&p) - p.buf > 0) { |
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put_byte(pb, pbBufPtr(&p) - p.buf); /* byte count of the packet */ |
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put_buffer(pb, p.buf, pbBufPtr(&p) - p.buf); /* the actual buffer */ |
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p.data_out_size += pbBufPtr(&p) - p.buf; |
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p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */ |
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} |
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if(left<=GIF_CHUNKS) { |
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put_byte(pb, 0x00); /* end of image block */ |
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} |
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left-=GIF_CHUNKS; |
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} |
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put_flush_packet(&s->pb); |
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return 0; |
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} |
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static int gif_write_packet(AVFormatContext *s, int stream_index, |
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UINT8 *buf, int size, int force_pts) |
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{ |
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AVCodecContext *codec = &s->streams[stream_index]->codec; |
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if (codec->codec_type == CODEC_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, buf, size); |
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} |
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static int gif_write_trailer(AVFormatContext *s) |
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{ |
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GIFContext *gif = s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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put_byte(pb, 0x3b); |
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put_flush_packet(&s->pb); |
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free(gif); |
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return 0; |
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} |
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AVFormat gif_format = { |
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"gif", |
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"GIF Animation", |
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"image/gif", |
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"gif", |
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CODEC_ID_NONE, |
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CODEC_ID_RAWVIDEO, |
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gif_write_header, |
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gif_write_packet, |
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gif_write_trailer, |
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NULL, /* read_header */ |
|
NULL, /* read_packet */ |
|
NULL, /* read_close */ |
|
};
|
|
|