diff options
Diffstat (limited to 'libavcodec/gif.c')
-rw-r--r-- | libavcodec/gif.c | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/libavcodec/gif.c b/libavcodec/gif.c index af57fff..de3e576 100644 --- a/libavcodec/gif.c +++ b/libavcodec/gif.c @@ -4,20 +4,20 @@ * Copyright (c) 2002 Francois Revol * Copyright (c) 2006 Baptiste Coudurier * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * 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. * - * Libav is distributed in the hope that it will be useful, + * 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 Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -25,8 +25,6 @@ * 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). * @@ -34,11 +32,6 @@ * 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 "avcodec.h" @@ -63,7 +56,7 @@ static int gif_image_write_header(AVCodecContext *avctx, uint8_t **bytestream, uint32_t *palette) { int i; - unsigned int v; + unsigned int v, smallest_alpha = 0xFF, alpha_component = 0; bytestream_put_buffer(bytestream, "GIF", 3); bytestream_put_buffer(bytestream, "89a", 3); @@ -78,6 +71,20 @@ static int gif_image_write_header(AVCodecContext *avctx, for(i=0;i<256;i++) { v = palette[i]; bytestream_put_be24(bytestream, v); + if (v >> 24 < smallest_alpha) { + smallest_alpha = v >> 24; + alpha_component = i; + } + } + + if (smallest_alpha < 128) { + bytestream_put_byte(bytestream, 0x21); /* Extension Introducer */ + bytestream_put_byte(bytestream, 0xf9); /* Graphic Control Label */ + bytestream_put_byte(bytestream, 0x04); /* block length */ + bytestream_put_byte(bytestream, 0x01); /* Transparent Color Flag */ + bytestream_put_le16(bytestream, 0x00); /* no delay */ + bytestream_put_byte(bytestream, alpha_component); + bytestream_put_byte(bytestream, 0x00); } return 0; @@ -131,6 +138,11 @@ static av_cold int gif_encode_init(AVCodecContext *avctx) { GIFContext *s = avctx->priv_data; + if (avctx->width > 65535 || avctx->height > 65535) { + av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n"); + return -1; + } + avctx->coded_frame = &s->picture; s->lzw = av_mallocz(ff_lzw_encode_state_size); if (!s->lzw) @@ -150,10 +162,8 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, uint8_t *outbuf_ptr, *end; int ret; - if ((ret = ff_alloc_packet(pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0) { - av_log(avctx, AV_LOG_ERROR, "Error getting output packet.\n"); + if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0) return ret; - } outbuf_ptr = pkt->data; end = pkt->data + pkt->size; |