diff options
| author | Tim Redfern <tim@eclectronics.org> | 2013-09-05 17:57:22 +0100 |
|---|---|---|
| committer | Tim Redfern <tim@eclectronics.org> | 2013-09-05 17:57:22 +0100 |
| commit | 8992cb1d0d07edc33d274f6d7924ecdf6f83d994 (patch) | |
| tree | 3a2c86846b7eec8137c1507e623fc7018f13d453 /ffmpeg/libavcodec/gif.c | |
| parent | 741fb4b9e135cfb161a749db88713229038577bb (diff) | |
making act segmenter
Diffstat (limited to 'ffmpeg/libavcodec/gif.c')
| -rw-r--r-- | ffmpeg/libavcodec/gif.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/gif.c b/ffmpeg/libavcodec/gif.c new file mode 100644 index 0000000..de3e576 --- /dev/null +++ b/ffmpeg/libavcodec/gif.c @@ -0,0 +1,205 @@ +/* + * GIF encoder. + * Copyright (c) 2000 Fabrice Bellard + * Copyright (c) 2002 Francois Revol + * Copyright (c) 2006 Baptiste Coudurier + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* + * First version by Francois Revol revol@free.fr + * + * Features and limitations: + * - uses only a global standard palette + * - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS). + * + * Reference documents: + * http://www.goice.co.jp/member/mo/formats/gif.html + * http://astronomy.swin.edu.au/pbourke/dataformats/gif/ + * http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt + */ + +#include "avcodec.h" +#include "bytestream.h" +#include "internal.h" +#include "lzw.h" + +/* The GIF format uses reversed order for bitstreams... */ +/* at least they don't use PDP_ENDIAN :) */ +#define BITSTREAM_WRITER_LE + +#include "put_bits.h" + +typedef struct { + AVFrame picture; + LZWState *lzw; + uint8_t *buf; +} GIFContext; + +/* GIF header */ +static int gif_image_write_header(AVCodecContext *avctx, + uint8_t **bytestream, uint32_t *palette) +{ + int i; + unsigned int v, smallest_alpha = 0xFF, alpha_component = 0; + + bytestream_put_buffer(bytestream, "GIF", 3); + bytestream_put_buffer(bytestream, "89a", 3); + bytestream_put_le16(bytestream, avctx->width); + bytestream_put_le16(bytestream, avctx->height); + + bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */ + bytestream_put_byte(bytestream, 0x1f); /* background color index */ + bytestream_put_byte(bytestream, 0); /* aspect ratio */ + + /* the global palette */ + 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; +} + +static int gif_image_write_image(AVCodecContext *avctx, + uint8_t **bytestream, uint8_t *end, + const uint8_t *buf, int linesize) +{ + GIFContext *s = avctx->priv_data; + int len = 0, height; + const uint8_t *ptr; + /* image block */ + + bytestream_put_byte(bytestream, 0x2c); + bytestream_put_le16(bytestream, 0); + bytestream_put_le16(bytestream, 0); + bytestream_put_le16(bytestream, avctx->width); + bytestream_put_le16(bytestream, avctx->height); + bytestream_put_byte(bytestream, 0x00); /* flags */ + /* no local clut */ + + bytestream_put_byte(bytestream, 0x08); + + ff_lzw_encode_init(s->lzw, s->buf, avctx->width*avctx->height, + 12, FF_LZW_GIF, put_bits); + + ptr = buf; + for (height = avctx->height; height--;) { + len += ff_lzw_encode(s->lzw, ptr, avctx->width); + ptr += linesize; + } + len += ff_lzw_encode_flush(s->lzw, flush_put_bits); + + ptr = s->buf; + while (len > 0) { + int size = FFMIN(255, len); + bytestream_put_byte(bytestream, size); + if (end - *bytestream < size) + return -1; + bytestream_put_buffer(bytestream, ptr, size); + ptr += size; + len -= size; + } + bytestream_put_byte(bytestream, 0x00); /* end of image block */ + bytestream_put_byte(bytestream, 0x3b); + return 0; +} + +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) + return AVERROR(ENOMEM); + s->buf = av_malloc(avctx->width*avctx->height*2); + if (!s->buf) + return AVERROR(ENOMEM); + return 0; +} + +/* better than nothing gif encoder */ +static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, + const AVFrame *pict, int *got_packet) +{ + GIFContext *s = avctx->priv_data; + AVFrame *const p = &s->picture; + uint8_t *outbuf_ptr, *end; + int ret; + + 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; + + *p = *pict; + p->pict_type = AV_PICTURE_TYPE_I; + p->key_frame = 1; + gif_image_write_header(avctx, &outbuf_ptr, (uint32_t *)pict->data[1]); + gif_image_write_image(avctx, &outbuf_ptr, end, pict->data[0], pict->linesize[0]); + + pkt->size = outbuf_ptr - pkt->data; + pkt->flags |= AV_PKT_FLAG_KEY; + *got_packet = 1; + + return 0; +} + +static int gif_encode_close(AVCodecContext *avctx) +{ + GIFContext *s = avctx->priv_data; + + av_freep(&s->lzw); + av_freep(&s->buf); + return 0; +} + +AVCodec ff_gif_encoder = { + .name = "gif", + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_GIF, + .priv_data_size = sizeof(GIFContext), + .init = gif_encode_init, + .encode2 = gif_encode_frame, + .close = gif_encode_close, + .pix_fmts = (const enum AVPixelFormat[]){ + AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE, + AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE + }, + .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), +}; 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