| 1 | /* |
| 2 | * Copyright (c) 2000 Fabrice Bellard |
| 3 | * Copyright (c) 2002 Francois Revol |
| 4 | * Copyright (c) 2006 Baptiste Coudurier |
| 5 | * |
| 6 | * first version by Francois Revol <revol@free.fr> |
| 7 | * |
| 8 | * This file is part of FFmpeg. |
| 9 | * |
| 10 | * FFmpeg is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU Lesser General Public |
| 12 | * License as published by the Free Software Foundation; either |
| 13 | * version 2.1 of the License, or (at your option) any later version. |
| 14 | * |
| 15 | * FFmpeg is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 18 | * Lesser General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Lesser General Public |
| 21 | * License along with FFmpeg; if not, write to the Free Software |
| 22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 23 | */ |
| 24 | |
| 25 | /** |
| 26 | * @file |
| 27 | * GIF encoder |
| 28 | * @see http://www.w3.org/Graphics/GIF/spec-gif89a.txt |
| 29 | */ |
| 30 | |
| 31 | #define BITSTREAM_WRITER_LE |
| 32 | #include "libavutil/opt.h" |
| 33 | #include "libavutil/imgutils.h" |
| 34 | #include "avcodec.h" |
| 35 | #include "bytestream.h" |
| 36 | #include "internal.h" |
| 37 | #include "lzw.h" |
| 38 | #include "gif.h" |
| 39 | |
| 40 | #include "put_bits.h" |
| 41 | |
| 42 | typedef struct { |
| 43 | const AVClass *class; |
| 44 | LZWState *lzw; |
| 45 | uint8_t *buf; |
| 46 | AVFrame *last_frame; |
| 47 | int flags; |
| 48 | uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8 |
| 49 | uint8_t *tmpl; ///< temporary line buffer |
| 50 | } GIFContext; |
| 51 | |
| 52 | enum { |
| 53 | GF_OFFSETTING = 1<<0, |
| 54 | GF_TRANSDIFF = 1<<1, |
| 55 | }; |
| 56 | |
| 57 | static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h) |
| 58 | { |
| 59 | int histogram[AVPALETTE_COUNT] = {0}; |
| 60 | int x, y, i; |
| 61 | |
| 62 | for (y = 0; y < h; y++) { |
| 63 | for (x = 0; x < w; x++) |
| 64 | histogram[buf[x]]++; |
| 65 | buf += linesize; |
| 66 | } |
| 67 | for (i = 0; i < FF_ARRAY_ELEMS(histogram); i++) |
| 68 | if (!histogram[i]) |
| 69 | return i; |
| 70 | return -1; |
| 71 | } |
| 72 | |
| 73 | static int gif_image_write_image(AVCodecContext *avctx, |
| 74 | uint8_t **bytestream, uint8_t *end, |
| 75 | const uint32_t *palette, |
| 76 | const uint8_t *buf, const int linesize, |
| 77 | AVPacket *pkt) |
| 78 | { |
| 79 | GIFContext *s = avctx->priv_data; |
| 80 | int len = 0, height = avctx->height, width = avctx->width, x, y; |
| 81 | int x_start = 0, y_start = 0, trans = -1; |
| 82 | const uint8_t *ptr; |
| 83 | |
| 84 | /* Crop image */ |
| 85 | // TODO support with palette change |
| 86 | if ((s->flags & GF_OFFSETTING) && s->last_frame && !palette) { |
| 87 | const uint8_t *ref = s->last_frame->data[0]; |
| 88 | const int ref_linesize = s->last_frame->linesize[0]; |
| 89 | int x_end = avctx->width - 1, |
| 90 | y_end = avctx->height - 1; |
| 91 | |
| 92 | /* skip common lines */ |
| 93 | while (y_start < y_end) { |
| 94 | if (memcmp(ref + y_start*ref_linesize, buf + y_start*linesize, width)) |
| 95 | break; |
| 96 | y_start++; |
| 97 | } |
| 98 | while (y_end > y_start) { |
| 99 | if (memcmp(ref + y_end*ref_linesize, buf + y_end*linesize, width)) |
| 100 | break; |
| 101 | y_end--; |
| 102 | } |
| 103 | height = y_end + 1 - y_start; |
| 104 | |
| 105 | /* skip common columns */ |
| 106 | while (x_start < x_end) { |
| 107 | int same_column = 1; |
| 108 | for (y = y_start; y < y_end; y++) { |
| 109 | if (ref[y*ref_linesize + x_start] != buf[y*linesize + x_start]) { |
| 110 | same_column = 0; |
| 111 | break; |
| 112 | } |
| 113 | } |
| 114 | if (!same_column) |
| 115 | break; |
| 116 | x_start++; |
| 117 | } |
| 118 | while (x_end > x_start) { |
| 119 | int same_column = 1; |
| 120 | for (y = y_start; y < y_end; y++) { |
| 121 | if (ref[y*ref_linesize + x_end] != buf[y*linesize + x_end]) { |
| 122 | same_column = 0; |
| 123 | break; |
| 124 | } |
| 125 | } |
| 126 | if (!same_column) |
| 127 | break; |
| 128 | x_end--; |
| 129 | } |
| 130 | width = x_end + 1 - x_start; |
| 131 | |
| 132 | av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n", |
| 133 | width, height, x_start, y_start, avctx->width, avctx->height); |
| 134 | } |
| 135 | |
| 136 | /* image block */ |
| 137 | bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR); |
| 138 | bytestream_put_le16(bytestream, x_start); |
| 139 | bytestream_put_le16(bytestream, y_start); |
| 140 | bytestream_put_le16(bytestream, width); |
| 141 | bytestream_put_le16(bytestream, height); |
| 142 | |
| 143 | if (!palette) { |
| 144 | bytestream_put_byte(bytestream, 0x00); /* flags */ |
| 145 | } else { |
| 146 | unsigned i; |
| 147 | bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */ |
| 148 | for (i = 0; i < AVPALETTE_COUNT; i++) { |
| 149 | const uint32_t v = palette[i]; |
| 150 | bytestream_put_be24(bytestream, v); |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | /* TODO: support with palette change (pal8) */ |
| 155 | if ((s->flags & GF_TRANSDIFF) && s->last_frame && !palette) { |
| 156 | trans = pick_palette_entry(buf + y_start*linesize + x_start, |
| 157 | linesize, width, height); |
| 158 | if (trans < 0) { // TODO, patch welcome |
| 159 | av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n"); |
| 160 | } else { |
| 161 | uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE); |
| 162 | if (!pal_exdata) |
| 163 | return AVERROR(ENOMEM); |
| 164 | memcpy(pal_exdata, s->palette, AVPALETTE_SIZE); |
| 165 | pal_exdata[trans*4 + 3*!HAVE_BIGENDIAN] = 0x00; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | bytestream_put_byte(bytestream, 0x08); |
| 170 | |
| 171 | ff_lzw_encode_init(s->lzw, s->buf, 2 * width * height, |
| 172 | 12, FF_LZW_GIF, put_bits); |
| 173 | |
| 174 | ptr = buf + y_start*linesize + x_start; |
| 175 | if (trans >= 0) { |
| 176 | const int ref_linesize = s->last_frame->linesize[0]; |
| 177 | const uint8_t *ref = s->last_frame->data[0] + y_start*ref_linesize + x_start; |
| 178 | |
| 179 | for (y = 0; y < height; y++) { |
| 180 | memcpy(s->tmpl, ptr, width); |
| 181 | for (x = 0; x < width; x++) |
| 182 | if (ref[x] == ptr[x]) |
| 183 | s->tmpl[x] = trans; |
| 184 | len += ff_lzw_encode(s->lzw, s->tmpl, width); |
| 185 | ptr += linesize; |
| 186 | ref += ref_linesize; |
| 187 | } |
| 188 | } else { |
| 189 | for (y = 0; y < height; y++) { |
| 190 | len += ff_lzw_encode(s->lzw, ptr, width); |
| 191 | ptr += linesize; |
| 192 | } |
| 193 | } |
| 194 | len += ff_lzw_encode_flush(s->lzw, flush_put_bits); |
| 195 | |
| 196 | ptr = s->buf; |
| 197 | while (len > 0) { |
| 198 | int size = FFMIN(255, len); |
| 199 | bytestream_put_byte(bytestream, size); |
| 200 | if (end - *bytestream < size) |
| 201 | return -1; |
| 202 | bytestream_put_buffer(bytestream, ptr, size); |
| 203 | ptr += size; |
| 204 | len -= size; |
| 205 | } |
| 206 | bytestream_put_byte(bytestream, 0x00); /* end of image block */ |
| 207 | return 0; |
| 208 | } |
| 209 | |
| 210 | static av_cold int gif_encode_init(AVCodecContext *avctx) |
| 211 | { |
| 212 | GIFContext *s = avctx->priv_data; |
| 213 | |
| 214 | if (avctx->width > 65535 || avctx->height > 65535) { |
| 215 | av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n"); |
| 216 | return AVERROR(EINVAL); |
| 217 | } |
| 218 | |
| 219 | avctx->coded_frame = av_frame_alloc(); |
| 220 | if (!avctx->coded_frame) |
| 221 | return AVERROR(ENOMEM); |
| 222 | |
| 223 | avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I; |
| 224 | avctx->coded_frame->key_frame = 1; |
| 225 | |
| 226 | s->lzw = av_mallocz(ff_lzw_encode_state_size); |
| 227 | s->buf = av_malloc(avctx->width*avctx->height*2); |
| 228 | s->tmpl = av_malloc(avctx->width); |
| 229 | if (!s->tmpl || !s->buf || !s->lzw) |
| 230 | return AVERROR(ENOMEM); |
| 231 | |
| 232 | if (avpriv_set_systematic_pal2(s->palette, avctx->pix_fmt) < 0) |
| 233 | av_assert0(avctx->pix_fmt == AV_PIX_FMT_PAL8); |
| 234 | |
| 235 | return 0; |
| 236 | } |
| 237 | |
| 238 | static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, |
| 239 | const AVFrame *pict, int *got_packet) |
| 240 | { |
| 241 | GIFContext *s = avctx->priv_data; |
| 242 | uint8_t *outbuf_ptr, *end; |
| 243 | const uint32_t *palette = NULL; |
| 244 | int ret; |
| 245 | |
| 246 | if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0) |
| 247 | return ret; |
| 248 | outbuf_ptr = pkt->data; |
| 249 | end = pkt->data + pkt->size; |
| 250 | |
| 251 | if (avctx->pix_fmt == AV_PIX_FMT_PAL8) { |
| 252 | uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE); |
| 253 | if (!pal_exdata) |
| 254 | return AVERROR(ENOMEM); |
| 255 | memcpy(pal_exdata, pict->data[1], AVPALETTE_SIZE); |
| 256 | palette = (uint32_t*)pict->data[1]; |
| 257 | } |
| 258 | |
| 259 | gif_image_write_image(avctx, &outbuf_ptr, end, palette, |
| 260 | pict->data[0], pict->linesize[0], pkt); |
| 261 | if (!s->last_frame) { |
| 262 | s->last_frame = av_frame_alloc(); |
| 263 | if (!s->last_frame) |
| 264 | return AVERROR(ENOMEM); |
| 265 | } |
| 266 | av_frame_unref(s->last_frame); |
| 267 | ret = av_frame_ref(s->last_frame, (AVFrame*)pict); |
| 268 | if (ret < 0) |
| 269 | return ret; |
| 270 | |
| 271 | pkt->size = outbuf_ptr - pkt->data; |
| 272 | pkt->flags |= AV_PKT_FLAG_KEY; |
| 273 | *got_packet = 1; |
| 274 | |
| 275 | return 0; |
| 276 | } |
| 277 | |
| 278 | static int gif_encode_close(AVCodecContext *avctx) |
| 279 | { |
| 280 | GIFContext *s = avctx->priv_data; |
| 281 | |
| 282 | av_frame_free(&avctx->coded_frame); |
| 283 | |
| 284 | av_freep(&s->lzw); |
| 285 | av_freep(&s->buf); |
| 286 | av_frame_free(&s->last_frame); |
| 287 | av_freep(&s->tmpl); |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | #define OFFSET(x) offsetof(GIFContext, x) |
| 292 | #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM |
| 293 | static const AVOption gif_options[] = { |
| 294 | { "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, "flags" }, |
| 295 | { "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" }, |
| 296 | { "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "flags" }, |
| 297 | { NULL } |
| 298 | }; |
| 299 | |
| 300 | static const AVClass gif_class = { |
| 301 | .class_name = "GIF encoder", |
| 302 | .item_name = av_default_item_name, |
| 303 | .option = gif_options, |
| 304 | .version = LIBAVUTIL_VERSION_INT, |
| 305 | }; |
| 306 | |
| 307 | AVCodec ff_gif_encoder = { |
| 308 | .name = "gif", |
| 309 | .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), |
| 310 | .type = AVMEDIA_TYPE_VIDEO, |
| 311 | .id = AV_CODEC_ID_GIF, |
| 312 | .priv_data_size = sizeof(GIFContext), |
| 313 | .init = gif_encode_init, |
| 314 | .encode2 = gif_encode_frame, |
| 315 | .close = gif_encode_close, |
| 316 | .pix_fmts = (const enum AVPixelFormat[]){ |
| 317 | AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE, |
| 318 | AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE |
| 319 | }, |
| 320 | .priv_class = &gif_class, |
| 321 | }; |