diff options
Diffstat (limited to 'libavcodec/gifdec.c')
| -rw-r--r-- | libavcodec/gifdec.c | 391 |
1 files changed, 305 insertions, 86 deletions
diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c index 4bb77895ad..3e3c9a5394 100644 --- a/libavcodec/gifdec.c +++ b/libavcodec/gifdec.c @@ -2,50 +2,67 @@ * 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 */ //#define DEBUG #include "libavutil/imgutils.h" +#include "libavutil/opt.h" #include "avcodec.h" #include "bytestream.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 picture; 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 */ const uint8_t *bytestream; @@ -53,20 +70,78 @@ typedef struct GifState { 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 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(const uint8_t **buf, uint32_t *pal, int nb) +{ + const uint8_t *pal_end = *buf + nb * 3; + + for (; *buf < pal_end; *buf += 3, pal++) + *pal = (0xffu << 24) | AV_RB24(*buf); +} + +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 + (t + 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_pr, + *src_py = src + y_start, + *dst_py = dst + y_start; + const uint32_t *src_pb = src_py + (t + 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; + src_pr = src_px + w; + + for (; src_px < src_pr; src_px++, dst_px++) + *dst_px = *src_px; + } +} static int gif_read_image(GifState *s) { 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; + 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 (s->bytestream_end < s->bytestream + 9) + return AVERROR_INVALIDDATA; left = bytestream_get_le16(&s->bytestream); top = bytestream_get_le16(&s->bytestream); @@ -77,14 +152,34 @@ static int gif_read_image(GifState *s) 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) { - bytestream_get_buffer(&s->bytestream, s->local_palette, 3 * (1 << bits_per_pixel)); - palette = s->local_palette; + pal_size = 1 << bits_per_pixel; + + if (s->bytestream_end < s->bytestream + pal_size * 3) + return AVERROR_INVALIDDATA; + + gif_read_palette(&s->bytestream, 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_FATAL, "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(&s->picture, s->bg_color); + } else { + /* otherwise fill with transparent color. + * this is necessary since by default picture filled with 0x80808080. */ + gif_fill(&s->picture, s->trans_color); + } } /* verify that all the image is inside the screen dimensions */ @@ -92,32 +187,64 @@ static int gif_read_image(GifState *s) top + height > s->screen_height) return AVERROR(EINVAL); - /* 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; + /* process disposal method */ + if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) { + gif_fill_rect(&s->picture, 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 *)s->picture.data[0], + s->picture.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 = width; s->gce_h = height; + + if (s->gce_disposal == GCE_DISPOSAL_BACKGROUND) { + if (s->background_color_index == s->transparent_color_index) + 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, s->picture.linesize[0] * s->picture.height); + if (!s->stored_img) + return AVERROR(ENOMEM); + + gif_copy_img_rect((uint32_t *)s->picture.data[0], s->stored_img, + s->picture.linesize[0] / sizeof(uint32_t), left, top, width, 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 (s->bytestream_end < s->bytestream + 2) + return AVERROR_INVALIDDATA; /* now get the image data */ code_size = bytestream_get_byte(&s->bytestream); - ff_lzw_decode_init(s->lzw, code_size, s->bytestream, - s->bytestream_end - s->bytestream, FF_LZW_GIF); + if ((ret = ff_lzw_decode_init(s->lzw, code_size, s->bytestream, + s->bytestream_end - s->bytestream, FF_LZW_GIF)) < 0) { + av_log(s->avctx, AV_LOG_ERROR, "LZW init failed\n"); + return ret; + } /* read all the image */ - linesize = s->picture.linesize[0]; - ptr1 = s->picture.data[0] + top * linesize + left; + linesize = s->picture.linesize[0] / sizeof(uint32_t); + ptr1 = (uint32_t *)s->picture.data[0] + top * linesize + left; ptr = ptr1; pass = 0; y1 = 0; for (y = 0; y < height; y++) { - ff_lzw_decode(s->lzw, ptr, width); + if (ff_lzw_decode(s->lzw, s->idx_line, width) == 0) + goto decode_tail; + + pr = ptr + width; + + 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: @@ -149,9 +276,17 @@ static int gif_read_image(GifState *s) ptr += linesize; } } + + decode_tail: /* read the garbage data until end marker is found */ ff_lzw_decode_tail(s->lzw); s->bytestream = ff_lzw_cur_ptr(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; } @@ -159,19 +294,29 @@ static int gif_read_extension(GifState *s) { int ext_code, ext_len, i, gce_flags, gce_transparent_index; - /* extension */ + /* There must be at least 2 bytes: + * 1 for extension label and 1 for extension length. */ + if (s->bytestream_end < s->bytestream + 2) + return AVERROR_INVALIDDATA; + ext_code = bytestream_get_byte(&s->bytestream); ext_len = bytestream_get_byte(&s->bytestream); - 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; + + /* We need at least 5 bytes more: 4 is for extension body + * and 1 for next block size. */ + if (s->bytestream_end < s->bytestream + 5) + return AVERROR_INVALIDDATA; + s->transparent_color_index = -1; gce_flags = bytestream_get_byte(&s->bytestream); - s->gce_delay = bytestream_get_le16(&s->bytestream); + bytestream_get_le16(&s->bytestream); // delay during which the frame is shown gce_transparent_index = bytestream_get_byte(&s->bytestream); if (gce_flags & 0x01) s->transparent_color_index = gce_transparent_index; @@ -179,10 +324,15 @@ static int gif_read_extension(GifState *s) 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); + 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 = bytestream_get_byte(&s->bytestream); break; } @@ -190,11 +340,15 @@ static int gif_read_extension(GifState *s) /* NOTE: many extension blocks can come after */ discard_ext: while (ext_len != 0) { + /* There must be at least ext_len bytes and 1 for next block size byte. */ + if (s->bytestream_end < s->bytestream + ext_len + 1) + return AVERROR_INVALIDDATA; + for (i = 0; i < ext_len; i++) bytestream_get_byte(&s->bytestream); ext_len = bytestream_get_byte(&s->bytestream); - av_dlog(s->avctx, "gif: ext_len1=%d\n", ext_len); + av_dlog(s->avctx, "ext_len1=%d\n", ext_len); } return 0; } @@ -203,16 +357,16 @@ static int gif_read_header1(GifState *s) { uint8_t sig[6]; int v, n; - int has_global_palette; + int background_color_index; if (s->bytestream_end < s->bytestream + 13) - return -1; + return AVERROR_INVALIDDATA; /* read gif signature */ bytestream_get_buffer(&s->bytestream, sig, 6); if (memcmp(sig, gif87a_sig, 6) != 0 && memcmp(sig, gif89a_sig, 6) != 0) - return -1; + return AVERROR_INVALIDDATA; /* read screen header */ s->transparent_color_index = -1; @@ -220,52 +374,69 @@ static int gif_read_header1(GifState *s) s->screen_height = bytestream_get_le16(&s->bytestream); if( (unsigned)s->screen_width > 32767 || (unsigned)s->screen_height > 32767){ - av_log(NULL, AV_LOG_ERROR, "picture size too large\n"); - return -1; + av_log(s->avctx, AV_LOG_ERROR, "picture size too large\n"); + return AVERROR_INVALIDDATA; } + av_fast_malloc(&s->idx_line, &s->idx_line_size, s->screen_width); + if (!s->idx_line) + return AVERROR(ENOMEM); + v = bytestream_get_byte(&s->bytestream); 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 = bytestream_get_byte(&s->bytestream); - bytestream_get_byte(&s->bytestream); /* ignored */ + background_color_index = bytestream_get_byte(&s->bytestream); + n = bytestream_get_byte(&s->bytestream); + 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 (s->bytestream_end < s->bytestream + n * 3) - return -1; - bytestream_get_buffer(&s->bytestream, s->global_palette, n * 3); - } + return AVERROR_INVALIDDATA; + + gif_read_palette(&s->bytestream, s->global_palette, n); + s->bg_color = s->global_palette[s->background_color_index]; + } else + s->background_color_index = -1; + return 0; } -static int gif_parse_next_image(GifState *s) +static int gif_parse_next_image(GifState *s, int *got_picture) { + int ret; + *got_picture = sizeof(AVPicture); while (s->bytestream < s->bytestream_end) { int code = bytestream_get_byte(&s->bytestream); - av_dlog(s->avctx, "gif: code=%02x '%c'\n", code, code); + av_dlog(s->avctx, "code=%02x '%c'\n", code, code); switch (code) { - case ',': + case GIF_IMAGE_SEPARATOR: return gif_read_image(s); - case '!': - if (gif_read_extension(s) < 0) - return -1; + case GIF_EXTENSION_INTRODUCER: + if ((ret = gif_read_extension(s)) < 0) + return ret; break; - case ';': + case GIF_TRAILER: /* end of image */ + *got_picture = 0; + return 0; default: - /* error or erroneous EOF */ - return -1; + /* erroneous block label */ + return AVERROR_INVALIDDATA; } } - return -1; + return AVERROR_EOF; } static av_cold int gif_decode_init(AVCodecContext *avctx) @@ -274,6 +445,7 @@ static av_cold int gif_decode_init(AVCodecContext *avctx) s->avctx = avctx; + avctx->pix_fmt = AV_PIX_FMT_RGB32; avcodec_get_frame_defaults(&s->picture); avctx->coded_frame= &s->picture; s->picture.data[0] = NULL; @@ -281,7 +453,7 @@ static av_cold int gif_decode_init(AVCodecContext *avctx) return 0; } -static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) +static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_picture, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; @@ -289,29 +461,55 @@ static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, A AVFrame *picture = data; int ret; + s->picture.pts = avpkt->pts; + s->picture.pkt_pts = avpkt->pts; + s->picture.pkt_dts = avpkt->dts; + s->picture.pkt_duration = avpkt->duration; + s->bytestream = buf; s->bytestream_end = buf + buf_size; - if (gif_read_header1(s) < 0) - return -1; - avctx->pix_fmt = AV_PIX_FMT_PAL8; - if (av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) - return -1; - avcodec_set_dimensions(avctx, s->screen_width, s->screen_height); + if (buf_size >= 6) { + s->keyframe = memcmp(s->bytestream, gif87a_sig, 6) == 0 || + memcmp(s->bytestream, gif89a_sig, 6) == 0; + } else { + s->keyframe = 0; + } - if (s->picture.data[0]) - avctx->release_buffer(avctx, &s->picture); - if (avctx->get_buffer(avctx, &s->picture) < 0) { - av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); - return -1; + if (s->keyframe) { + if ((ret = gif_read_header1(s)) < 0) + return ret; + + if ((ret = av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) < 0) + return ret; + avcodec_set_dimensions(avctx, s->screen_width, s->screen_height); + + if (s->picture.data[0]) + avctx->release_buffer(avctx, &s->picture); + + if ((ret = avctx->get_buffer(avctx, &s->picture)) < 0) { + av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); + return ret; + } + + s->picture.pict_type = AV_PICTURE_TYPE_I; + s->picture.key_frame = 1; + } else { + if ((ret = avctx->reget_buffer(avctx, &s->picture)) < 0) { + av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); + return ret; + } + + s->picture.pict_type = AV_PICTURE_TYPE_P; + s->picture.key_frame = 0; } - s->image_palette = (uint32_t *)s->picture.data[1]; - ret = gif_parse_next_image(s); + + ret = gif_parse_next_image(s, got_picture); if (ret < 0) return ret; + else if (*got_picture) + *picture = s->picture; - *picture = s->picture; - *data_size = sizeof(AVPicture); return s->bytestream - buf; } @@ -322,9 +520,29 @@ static av_cold int gif_decode_close(AVCodecContext *avctx) ff_lzw_decode_close(&s->lzw); if(s->picture.data[0]) avctx->release_buffer(avctx, &s->picture); + + 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", .type = AVMEDIA_TYPE_VIDEO, @@ -335,4 +553,5 @@ AVCodec ff_gif_decoder = { .decode = gif_decode_frame, .capabilities = CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), + .priv_class = &decoder_class, }; |