/* * Copyright (c) 2000 Fabrice Bellard * Copyright (c) 2002 Francois Revol * Copyright (c) 2006 Baptiste Coudurier * * first version by Francois Revol <revol@free.fr> * * 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 */ /** * @file * GIF encoder * @see http://www.w3.org/Graphics/GIF/spec-gif89a.txt */ #define BITSTREAM_WRITER_LE #include "libavutil/opt.h" #include "libavutil/imgutils.h" #include "avcodec.h" #include "bytestream.h" #include "internal.h" #include "lzw.h" #include "gif.h" #include "put_bits.h" typedef struct GIFContext { const AVClass *class; LZWState *lzw; uint8_t *buf; int buf_size; AVFrame *last_frame; int flags; uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8 int palette_loaded; int transparent_index; uint8_t *pal_exdata; uint8_t *tmpl; ///< temporary line buffer } GIFContext; enum { GF_OFFSETTING = 1<<0, GF_TRANSDIFF = 1<<1, }; static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h) { int histogram[AVPALETTE_COUNT] = {0}; int x, y, i; for (y = 0; y < h; y++) { for (x = 0; x < w; x++) histogram[buf[x]]++; buf += linesize; } for (i = 0; i < FF_ARRAY_ELEMS(histogram); i++) if (!histogram[i]) return i; return -1; } static int gif_image_write_image(AVCodecContext *avctx, uint8_t **bytestream, uint8_t *end, const uint32_t *palette, const uint8_t *buf, const int linesize, AVPacket *pkt) { GIFContext *s = avctx->priv_data; int len = 0, height = avctx->height, width = avctx->width, x, y; int x_start = 0, y_start = 0, trans = s->transparent_index; int honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette; const uint8_t *ptr; /* Crop image */ if ((s->flags & GF_OFFSETTING) && s->last_frame && !palette) { const uint8_t *ref = s->last_frame->data[0]; const int ref_linesize = s->last_frame->linesize[0]; int x_end = avctx->width - 1, y_end = avctx->height - 1; /* skip common lines */ while (y_start < y_end) { if (memcmp(ref + y_start*ref_linesize, buf + y_start*linesize, width)) break; y_start++; } while (y_end > y_start) { if (memcmp(ref + y_end*ref_linesize, buf + y_end*linesize, width)) break; y_end--; } height = y_end + 1 - y_start; /* skip common columns */ while (x_start < x_end) { int same_column = 1; for (y = y_start; y <= y_end; y++) { if (ref[y*ref_linesize + x_start] != buf[y*linesize + x_start]) { same_column = 0; break; } } if (!same_column) break; x_start++; } while (x_end > x_start) { int same_column = 1; for (y = y_start; y <= y_end; y++) { if (ref[y*ref_linesize + x_end] != buf[y*linesize + x_end]) { same_column = 0; break; } } if (!same_column) break; x_end--; } width = x_end + 1 - x_start; av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n", width, height, x_start, y_start, avctx->width, avctx->height); } /* image block */ bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR); bytestream_put_le16(bytestream, x_start); bytestream_put_le16(bytestream, y_start); bytestream_put_le16(bytestream, width); bytestream_put_le16(bytestream, height); if (!palette) { bytestream_put_byte(bytestream, 0x00); /* flags */ } else { unsigned i; bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */ for (i = 0; i < AVPALETTE_COUNT; i++) { const uint32_t v = palette[i]; bytestream_put_be24(bytestream, v); } } if (honor_transparency && trans < 0) { trans = pick_palette_entry(buf + y_start*linesize + x_start, linesize, width, height); if (trans < 0) { // TODO, patch welcome av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n"); } else { uint8_t *pal_exdata = s->pal_exdata; if (!pal_exdata) pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE); if (!pal_exdata) return AVERROR(ENOMEM); memcpy(pal_exdata, s->palette, AVPALETTE_SIZE); pal_exdata[trans*4 + 3*!HAVE_BIGENDIAN] = 0x00; } } if (trans < 0) honor_transparency = 0; bytestream_put_byte(bytestream, 0x08); ff_lzw_encode_init(s->lzw, s->buf, s->buf_size, 12, FF_LZW_GIF, put_bits); ptr = buf + y_start*linesize + x_start; if (honor_transparency) { const int ref_linesize = s->last_frame->linesize[0]; const uint8_t *ref = s->last_frame->data[0] + y_start*ref_linesize + x_start; for (y = 0; y < height; y++) { memcpy(s->tmpl, ptr, width); for (x = 0; x < width; x++) if (ref[x] == ptr[x]) s->tmpl[x] = trans; len += ff_lzw_encode(s->lzw, s->tmpl, width); ptr += linesize; ref += ref_linesize; } } else { for (y = 0; y < height; y++) { len += ff_lzw_encode(s->lzw, ptr, 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 */ 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 AVERROR(EINVAL); } #if FF_API_CODED_FRAME FF_DISABLE_DEPRECATION_WARNINGS avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I; avctx->coded_frame->key_frame = 1; FF_ENABLE_DEPRECATION_WARNINGS #endif s->transparent_index = -1; s->lzw = av_mallocz(ff_lzw_encode_state_size); s->buf_size = avctx->width*avctx->height*2 + 1000; s->buf = av_malloc(s->buf_size); s->tmpl = av_malloc(avctx->width); if (!s->tmpl || !s->buf || !s->lzw) return AVERROR(ENOMEM); if (avpriv_set_systematic_pal2(s->palette, avctx->pix_fmt) < 0) av_assert0(avctx->pix_fmt == AV_PIX_FMT_PAL8); return 0; } /* FIXME: duplicated with lavc */ static int get_palette_transparency_index(const uint32_t *palette) { int transparent_color_index = -1; unsigned i, smallest_alpha = 0xff; if (!palette) return -1; for (i = 0; i < AVPALETTE_COUNT; i++) { const uint32_t v = palette[i]; if (v >> 24 < smallest_alpha) { smallest_alpha = v >> 24; transparent_color_index = i; } } return smallest_alpha < 128 ? transparent_color_index : -1; } static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet) { GIFContext *s = avctx->priv_data; uint8_t *outbuf_ptr, *end; const uint32_t *palette = NULL; int ret; if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0) return ret; outbuf_ptr = pkt->data; end = pkt->data + pkt->size; if (avctx->pix_fmt == AV_PIX_FMT_PAL8) { uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE); if (!pal_exdata) return AVERROR(ENOMEM); memcpy(pal_exdata, pict->data[1], AVPALETTE_SIZE); palette = (uint32_t*)pict->data[1]; s->pal_exdata = pal_exdata; /* The first palette with PAL8 will be used as generic palette by the * muxer so we don't need to write it locally in the packet. We store * it as a reference here in case it changes later. */ if (!s->palette_loaded) { memcpy(s->palette, palette, AVPALETTE_SIZE); s->transparent_index = get_palette_transparency_index(palette); s->palette_loaded = 1; palette = NULL; } else if (!memcmp(s->palette, palette, AVPALETTE_SIZE)) { palette = NULL; } } gif_image_write_image(avctx, &outbuf_ptr, end, palette, pict->data[0], pict->linesize[0], pkt); if (!s->last_frame) { s->last_frame = av_frame_alloc(); if (!s->last_frame) return AVERROR(ENOMEM); } av_frame_unref(s->last_frame); ret = av_frame_ref(s->last_frame, (AVFrame*)pict); if (ret < 0) return ret; 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); s->buf_size = 0; av_frame_free(&s->last_frame); av_freep(&s->tmpl); return 0; } #define OFFSET(x) offsetof(GIFContext, x) #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM static const AVOption gif_options[] = { { "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, "flags" }, { "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" }, { "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "flags" }, { NULL } }; static const AVClass gif_class = { .class_name = "GIF encoder", .item_name = av_default_item_name, .option = gif_options, .version = LIBAVUTIL_VERSION_INT, }; AVCodec ff_gif_encoder = { .name = "gif", .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), .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 }, .priv_class = &gif_class, };