diff options
Diffstat (limited to 'libavcodec/gifdec.c')
-rw-r--r-- | libavcodec/gifdec.c | 457 |
1 files changed, 344 insertions, 113 deletions
diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c index df5ab78..9ba436e 100644 --- a/libavcodec/gifdec.c +++ b/libavcodec/gifdec.c @@ -2,122 +2,268 @@ * GIF decoder * Copyright (c) 2003 Fabrice Bellard * Copyright (c) 2006 Baptiste Coudurier + * Copyright (c) 2012 Vitaliy E Sugrobov * - * 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 */ #include "libavutil/imgutils.h" +#include "libavutil/opt.h" #include "avcodec.h" #include "bytestream.h" #include "internal.h" #include "lzw.h" +#include "gif.h" -#define GCE_DISPOSAL_NONE 0 -#define GCE_DISPOSAL_INPLACE 1 -#define GCE_DISPOSAL_BACKGROUND 2 -#define GCE_DISPOSAL_RESTORE 3 +/* This value is intentionally set to "transparent white" color. + * It is much better to have white background instead of black + * when gif image converted to format which not support transparency. + */ +#define GIF_TRANSPARENT_COLOR 0x00ffffff typedef struct GifState { + const AVClass *class; + AVFrame *frame; int screen_width; int screen_height; + int has_global_palette; int bits_per_pixel; + uint32_t bg_color; int background_color_index; int transparent_color_index; int color_resolution; - uint32_t *image_palette; + /* intermediate buffer for storing color indices + * obtained from lzw-encoded data stream */ + uint8_t *idx_line; + int idx_line_size; /* after the frame is displayed, the disposal method is used */ + int gce_prev_disposal; int gce_disposal; - /* delay during which the frame is shown */ - int gce_delay; + /* rectangle describing area that must be disposed */ + int gce_l, gce_t, gce_w, gce_h; + /* depending on disposal method we store either part of the image + * drawn on the canvas or background color that + * should be used upon disposal */ + uint32_t * stored_img; + int stored_img_size; + int stored_bg_color; - /* LZW compatible decoder */ GetByteContext gb; LZWState *lzw; /* aux buffers */ - uint8_t global_palette[256 * 3]; - uint8_t local_palette[256 * 3]; + uint32_t global_palette[256]; + uint32_t local_palette[256]; - AVCodecContext* avctx; + AVCodecContext *avctx; + int keyframe; + int keyframe_ok; + int trans_color; /**< color value that is used instead of transparent color */ } GifState; -static const uint8_t gif87a_sig[6] = "GIF87a"; -static const uint8_t gif89a_sig[6] = "GIF89a"; +static void gif_read_palette(GifState *s, uint32_t *pal, int nb) +{ + int i; + + for (i = 0; i < nb; i++, pal++) + *pal = (0xffu << 24) | bytestream2_get_be24u(&s->gb); +} + +static void gif_fill(AVFrame *picture, uint32_t color) +{ + uint32_t *p = (uint32_t *)picture->data[0]; + uint32_t *p_end = p + (picture->linesize[0] / sizeof(uint32_t)) * picture->height; + + for (; p < p_end; p++) + *p = color; +} + +static void gif_fill_rect(AVFrame *picture, uint32_t color, int l, int t, int w, int h) +{ + const int linesize = picture->linesize[0] / sizeof(uint32_t); + const uint32_t *py = (uint32_t *)picture->data[0] + t * linesize; + const uint32_t *pr, *pb = py + h * linesize; + uint32_t *px; + + for (; py < pb; py += linesize) { + px = (uint32_t *)py + l; + pr = px + w; + + for (; px < pr; px++) + *px = color; + } +} + +static void gif_copy_img_rect(const uint32_t *src, uint32_t *dst, + int linesize, int l, int t, int w, int h) +{ + const int y_start = t * linesize; + const uint32_t *src_px, + *src_py = src + y_start, + *dst_py = dst + y_start; + const uint32_t *src_pb = src_py + h * linesize; + uint32_t *dst_px; + + for (; src_py < src_pb; src_py += linesize, dst_py += linesize) { + src_px = src_py + l; + dst_px = (uint32_t *)dst_py + l; + + memcpy(dst_px, src_px, w * sizeof(uint32_t)); + } +} static int gif_read_image(GifState *s, AVFrame *frame) { - int left, top, width, height, bits_per_pixel, code_size, flags; - int is_interleaved, has_local_palette, y, pass, y1, linesize, n, i; - uint8_t *ptr, *spal, *palette, *ptr1; - - left = bytestream2_get_le16(&s->gb); - top = bytestream2_get_le16(&s->gb); - width = bytestream2_get_le16(&s->gb); - height = bytestream2_get_le16(&s->gb); - flags = bytestream2_get_byte(&s->gb); + int left, top, width, height, bits_per_pixel, code_size, flags, pw; + int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size; + uint32_t *ptr, *pal, *px, *pr, *ptr1; + int ret; + uint8_t *idx; + + /* At least 9 bytes of Image Descriptor. */ + if (bytestream2_get_bytes_left(&s->gb) < 9) + return AVERROR_INVALIDDATA; + + left = bytestream2_get_le16u(&s->gb); + top = bytestream2_get_le16u(&s->gb); + width = bytestream2_get_le16u(&s->gb); + height = bytestream2_get_le16u(&s->gb); + flags = bytestream2_get_byteu(&s->gb); is_interleaved = flags & 0x40; has_local_palette = flags & 0x80; bits_per_pixel = (flags & 0x07) + 1; - av_dlog(s->avctx, "gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height); + av_dlog(s->avctx, "image x=%d y=%d w=%d h=%d\n", left, top, width, height); if (has_local_palette) { - bytestream2_get_buffer(&s->gb, s->local_palette, 3 * (1 << bits_per_pixel)); - palette = s->local_palette; + pal_size = 1 << bits_per_pixel; + + if (bytestream2_get_bytes_left(&s->gb) < pal_size * 3) + return AVERROR_INVALIDDATA; + + gif_read_palette(s, s->local_palette, pal_size); + pal = s->local_palette; } else { - palette = s->global_palette; - bits_per_pixel = s->bits_per_pixel; + if (!s->has_global_palette) { + av_log(s->avctx, AV_LOG_ERROR, "picture doesn't have either global or local palette.\n"); + return AVERROR_INVALIDDATA; + } + + pal = s->global_palette; + } + + if (s->keyframe) { + if (s->transparent_color_index == -1 && s->has_global_palette) { + /* transparency wasn't set before the first frame, fill with background color */ + gif_fill(frame, s->bg_color); + } else { + /* otherwise fill with transparent color. + * this is necessary since by default picture filled with 0x80808080. */ + gif_fill(frame, s->trans_color); + } } /* verify that all the image is inside the screen dimensions */ - if (left + width > s->screen_width || - top + height > s->screen_height || - !width || !height) { - av_log(s->avctx, AV_LOG_ERROR, "Invalid image dimensions.\n"); + if (!width || width > s->screen_width || left >= s->screen_width) { + av_log(s->avctx, AV_LOG_ERROR, "Invalid image width.\n"); return AVERROR_INVALIDDATA; } + if (!height || height > s->screen_height || top >= s->screen_height) { + av_log(s->avctx, AV_LOG_ERROR, "Invalid image height.\n"); + return AVERROR_INVALIDDATA; + } + if (left + width > s->screen_width) { + /* width must be kept around to avoid lzw vs line desync */ + pw = s->screen_width - left; + av_log(s->avctx, AV_LOG_WARNING, "Image too wide by %d, truncating.\n", + left + width - s->screen_width); + } else { + pw = width; + } + if (top + height > s->screen_height) { + /* we don't care about the extra invisible lines */ + av_log(s->avctx, AV_LOG_WARNING, "Image too high by %d, truncating.\n", + top + height - s->screen_height); + height = s->screen_height - top; + } + + /* process disposal method */ + if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) { + gif_fill_rect(frame, s->stored_bg_color, s->gce_l, s->gce_t, s->gce_w, s->gce_h); + } else if (s->gce_prev_disposal == GCE_DISPOSAL_RESTORE) { + gif_copy_img_rect(s->stored_img, (uint32_t *)frame->data[0], + frame->linesize[0] / sizeof(uint32_t), s->gce_l, s->gce_t, s->gce_w, s->gce_h); + } + + s->gce_prev_disposal = s->gce_disposal; + + if (s->gce_disposal != GCE_DISPOSAL_NONE) { + s->gce_l = left; s->gce_t = top; + s->gce_w = pw; s->gce_h = height; - /* build the palette */ - n = (1 << bits_per_pixel); - spal = palette; - for(i = 0; i < n; i++) { - s->image_palette[i] = (0xffu << 24) | AV_RB24(spal); - spal += 3; + if (s->gce_disposal == GCE_DISPOSAL_BACKGROUND) { + if (s->transparent_color_index >= 0) + s->stored_bg_color = s->trans_color; + else + s->stored_bg_color = s->bg_color; + } else if (s->gce_disposal == GCE_DISPOSAL_RESTORE) { + av_fast_malloc(&s->stored_img, &s->stored_img_size, frame->linesize[0] * frame->height); + if (!s->stored_img) + return AVERROR(ENOMEM); + + gif_copy_img_rect((uint32_t *)frame->data[0], s->stored_img, + frame->linesize[0] / sizeof(uint32_t), left, top, pw, height); + } } - for(; i < 256; i++) - s->image_palette[i] = (0xffu << 24); - /* handle transparency */ - if (s->transparent_color_index >= 0) - s->image_palette[s->transparent_color_index] = 0; + + /* Expect at least 2 bytes: 1 for lzw code size and 1 for block size. */ + if (bytestream2_get_bytes_left(&s->gb) < 2) + return AVERROR_INVALIDDATA; /* now get the image data */ - code_size = bytestream2_get_byte(&s->gb); - ff_lzw_decode_init(s->lzw, code_size, s->gb.buffer, - bytestream2_get_bytes_left(&s->gb), FF_LZW_GIF); + code_size = bytestream2_get_byteu(&s->gb); + if ((ret = ff_lzw_decode_init(s->lzw, code_size, s->gb.buffer, + bytestream2_get_bytes_left(&s->gb), FF_LZW_GIF)) < 0) { + av_log(s->avctx, AV_LOG_ERROR, "LZW init failed\n"); + return ret; + } /* read all the image */ - linesize = frame->linesize[0]; - ptr1 = frame->data[0] + top * linesize + left; + linesize = frame->linesize[0] / sizeof(uint32_t); + ptr1 = (uint32_t *)frame->data[0] + top * linesize + left; ptr = ptr1; pass = 0; y1 = 0; for (y = 0; y < height; y++) { - ff_lzw_decode(s->lzw, ptr, width); + int count = ff_lzw_decode(s->lzw, s->idx_line, width); + if (count != width) { + if (count) + av_log(s->avctx, AV_LOG_ERROR, "LZW decode failed\n"); + goto decode_tail; + } + + pr = ptr + pw; + + for (px = ptr, idx = s->idx_line; px < pr; px++, idx++) { + if (*idx != s->transparent_color_index) + *px = pal[*idx]; + } + if (is_interleaved) { switch(pass) { default: @@ -144,53 +290,76 @@ static int gif_read_image(GifState *s, AVFrame *frame) ptr += linesize; } } + + decode_tail: /* read the garbage data until end marker is found */ ff_lzw_decode_tail(s->lzw); - bytestream2_skip(&s->gb, ff_lzw_size_read(s->lzw)); + /* Graphic Control Extension's scope is single frame. + * Remove its influence. */ + s->transparent_color_index = -1; + s->gce_disposal = GCE_DISPOSAL_NONE; + return 0; } static int gif_read_extension(GifState *s) { - int ext_code, ext_len, i, gce_flags, gce_transparent_index; + int ext_code, ext_len, gce_flags, gce_transparent_index; + + /* There must be at least 2 bytes: + * 1 for extension label and 1 for extension length. */ + if (bytestream2_get_bytes_left(&s->gb) < 2) + return AVERROR_INVALIDDATA; - /* extension */ - ext_code = bytestream2_get_byte(&s->gb); - ext_len = bytestream2_get_byte(&s->gb); + ext_code = bytestream2_get_byteu(&s->gb); + ext_len = bytestream2_get_byteu(&s->gb); - av_dlog(s->avctx, "gif: ext_code=0x%x len=%d\n", ext_code, ext_len); + av_dlog(s->avctx, "ext_code=0x%x len=%d\n", ext_code, ext_len); switch(ext_code) { - case 0xf9: + case GIF_GCE_EXT_LABEL: if (ext_len != 4) goto discard_ext; - s->transparent_color_index = -1; - gce_flags = bytestream2_get_byte(&s->gb); - s->gce_delay = bytestream2_get_le16(&s->gb); - gce_transparent_index = bytestream2_get_byte(&s->gb); + + /* We need at least 5 bytes more: 4 is for extension body + * and 1 for next block size. */ + if (bytestream2_get_bytes_left(&s->gb) < 5) + return AVERROR_INVALIDDATA; + + gce_flags = bytestream2_get_byteu(&s->gb); + bytestream2_skipu(&s->gb, 2); // delay during which the frame is shown + gce_transparent_index = bytestream2_get_byteu(&s->gb); if (gce_flags & 0x01) s->transparent_color_index = gce_transparent_index; else s->transparent_color_index = -1; s->gce_disposal = (gce_flags >> 2) & 0x7; - av_dlog(s->avctx, "gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n", - gce_flags, s->gce_delay, + av_dlog(s->avctx, "gce_flags=%x tcolor=%d disposal=%d\n", + gce_flags, s->transparent_color_index, s->gce_disposal); - ext_len = bytestream2_get_byte(&s->gb); + if (s->gce_disposal > 3) { + s->gce_disposal = GCE_DISPOSAL_NONE; + av_dlog(s->avctx, "invalid value in gce_disposal (%d). Using default value of 0.\n", ext_len); + } + + ext_len = bytestream2_get_byteu(&s->gb); break; } /* NOTE: many extension blocks can come after */ discard_ext: - while (ext_len != 0) { - for (i = 0; i < ext_len; i++) - bytestream2_get_byte(&s->gb); - ext_len = bytestream2_get_byte(&s->gb); + while (ext_len) { + /* There must be at least ext_len bytes and 1 for next block size byte. */ + if (bytestream2_get_bytes_left(&s->gb) < ext_len + 1) + return AVERROR_INVALIDDATA; + + bytestream2_skipu(&s->gb, ext_len); + ext_len = bytestream2_get_byteu(&s->gb); - av_dlog(s->avctx, "gif: ext_len1=%d\n", ext_len); + av_dlog(s->avctx, "ext_len1=%d\n", ext_len); } return 0; } @@ -199,44 +368,48 @@ static int gif_read_header1(GifState *s) { uint8_t sig[6]; int v, n; - int has_global_palette; + int background_color_index; if (bytestream2_get_bytes_left(&s->gb) < 13) return AVERROR_INVALIDDATA; /* read gif signature */ - bytestream2_get_buffer(&s->gb, sig, 6); - if (memcmp(sig, gif87a_sig, 6) != 0 && - memcmp(sig, gif89a_sig, 6) != 0) + bytestream2_get_bufferu(&s->gb, sig, 6); + if (memcmp(sig, gif87a_sig, 6) && + memcmp(sig, gif89a_sig, 6)) return AVERROR_INVALIDDATA; /* read screen header */ s->transparent_color_index = -1; - s->screen_width = bytestream2_get_le16(&s->gb); - s->screen_height = bytestream2_get_le16(&s->gb); - if( (unsigned)s->screen_width > 32767 - || (unsigned)s->screen_height > 32767){ - av_log(NULL, AV_LOG_ERROR, "picture size too large\n"); - return AVERROR_INVALIDDATA; - } + s->screen_width = bytestream2_get_le16u(&s->gb); + s->screen_height = bytestream2_get_le16u(&s->gb); - v = bytestream2_get_byte(&s->gb); + v = bytestream2_get_byteu(&s->gb); s->color_resolution = ((v & 0x70) >> 4) + 1; - has_global_palette = (v & 0x80); + s->has_global_palette = (v & 0x80); s->bits_per_pixel = (v & 0x07) + 1; - s->background_color_index = bytestream2_get_byte(&s->gb); - bytestream2_get_byte(&s->gb); /* ignored */ + background_color_index = bytestream2_get_byteu(&s->gb); + n = bytestream2_get_byteu(&s->gb); + if (n) { + s->avctx->sample_aspect_ratio.num = n + 15; + s->avctx->sample_aspect_ratio.den = 64; + } - av_dlog(s->avctx, "gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n", + av_dlog(s->avctx, "screen_w=%d screen_h=%d bpp=%d global_palette=%d\n", s->screen_width, s->screen_height, s->bits_per_pixel, - has_global_palette); + s->has_global_palette); - if (has_global_palette) { + if (s->has_global_palette) { + s->background_color_index = background_color_index; n = 1 << s->bits_per_pixel; if (bytestream2_get_bytes_left(&s->gb) < n * 3) return AVERROR_INVALIDDATA; - bytestream2_get_buffer(&s->gb, s->global_palette, n * 3); - } + + gif_read_palette(s, s->global_palette, n); + s->bg_color = s->global_palette[s->background_color_index]; + } else + s->background_color_index = -1; + return 0; } @@ -246,23 +419,24 @@ static int gif_parse_next_image(GifState *s, AVFrame *frame) int code = bytestream2_get_byte(&s->gb); int ret; - av_dlog(s->avctx, "gif: code=%02x '%c'\n", code, code); + av_log(s->avctx, AV_LOG_DEBUG, "code=%02x '%c'\n", code, code); switch (code) { - case ',': + case GIF_IMAGE_SEPARATOR: return gif_read_image(s, frame); - case '!': + case GIF_EXTENSION_INTRODUCER: if ((ret = gif_read_extension(s)) < 0) return ret; break; - case ';': + case GIF_TRAILER: /* end of image */ + return AVERROR_EOF; default: - /* error or erroneous EOF */ + /* erroneous block label */ return AVERROR_INVALIDDATA; } } - return AVERROR_INVALIDDATA; + return AVERROR_EOF; } static av_cold int gif_decode_init(AVCodecContext *avctx) @@ -271,38 +445,74 @@ static av_cold int gif_decode_init(AVCodecContext *avctx) s->avctx = avctx; + avctx->pix_fmt = AV_PIX_FMT_RGB32; + s->frame = av_frame_alloc(); + if (!s->frame) + return AVERROR(ENOMEM); ff_lzw_decode_open(&s->lzw); return 0; } -static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, - AVPacket *avpkt) +static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { - const uint8_t *buf = avpkt->data; - int buf_size = avpkt->size; GifState *s = avctx->priv_data; - AVFrame *picture = data; int ret; - bytestream2_init(&s->gb, buf, buf_size); - if ((ret = gif_read_header1(s)) < 0) - return ret; + bytestream2_init(&s->gb, avpkt->data, avpkt->size); - avctx->pix_fmt = AV_PIX_FMT_PAL8; + s->frame->pts = avpkt->pts; + s->frame->pkt_pts = avpkt->pts; + s->frame->pkt_dts = avpkt->dts; + av_frame_set_pkt_duration(s->frame, avpkt->duration); - if ((ret = ff_set_dimensions(avctx, s->screen_width, s->screen_height)) < 0) - return ret; + if (avpkt->size >= 6) { + s->keyframe = memcmp(avpkt->data, gif87a_sig, 6) == 0 || + memcmp(avpkt->data, gif89a_sig, 6) == 0; + } else { + s->keyframe = 0; + } - if ((ret = ff_get_buffer(avctx, picture, 0)) < 0) { - av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); - return ret; + if (s->keyframe) { + s->keyframe_ok = 0; + s->gce_prev_disposal = GCE_DISPOSAL_NONE; + if ((ret = gif_read_header1(s)) < 0) + return ret; + + if ((ret = ff_set_dimensions(avctx, s->screen_width, s->screen_height)) < 0) + return ret; + + av_frame_unref(s->frame); + if ((ret = ff_get_buffer(avctx, s->frame, 0)) < 0) + return ret; + + av_fast_malloc(&s->idx_line, &s->idx_line_size, s->screen_width); + if (!s->idx_line) + return AVERROR(ENOMEM); + + s->frame->pict_type = AV_PICTURE_TYPE_I; + s->frame->key_frame = 1; + s->keyframe_ok = 1; + } else { + if (!s->keyframe_ok) { + av_log(avctx, AV_LOG_ERROR, "cannot decode frame without keyframe\n"); + return AVERROR_INVALIDDATA; + } + + if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) + return ret; + + s->frame->pict_type = AV_PICTURE_TYPE_P; + s->frame->key_frame = 0; } - s->image_palette = (uint32_t *)picture->data[1]; - ret = gif_parse_next_image(s, picture); + + ret = gif_parse_next_image(s, s->frame); if (ret < 0) return ret; + if ((ret = av_frame_ref(data, s->frame)) < 0) + return ret; *got_frame = 1; + return bytestream2_tell(&s->gb); } @@ -311,9 +521,29 @@ static av_cold int gif_decode_close(AVCodecContext *avctx) GifState *s = avctx->priv_data; ff_lzw_decode_close(&s->lzw); + av_frame_free(&s->frame); + av_freep(&s->idx_line); + av_freep(&s->stored_img); + return 0; } +static const AVOption options[] = { + { "trans_color", "color value (ARGB) that is used instead of transparent color", + offsetof(GifState, trans_color), AV_OPT_TYPE_INT, + {.i64 = GIF_TRANSPARENT_COLOR}, 0, 0xffffffff, + AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_VIDEO_PARAM }, + { NULL }, +}; + +static const AVClass decoder_class = { + .class_name = "gif decoder", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, + .category = AV_CLASS_CATEGORY_DECODER, +}; + AVCodec ff_gif_decoder = { .name = "gif", .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), @@ -324,4 +554,5 @@ AVCodec ff_gif_decoder = { .close = gif_decode_close, .decode = gif_decode_frame, .capabilities = CODEC_CAP_DR1, + .priv_class = &decoder_class, }; |