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-rw-r--r--ffmpeg/libavcodec/gif.c205
1 files changed, 205 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/gif.c b/ffmpeg/libavcodec/gif.c
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+++ b/ffmpeg/libavcodec/gif.c
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+/*
+ * 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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