From 8f66d46ce5f41be8084ad14061cec8f8e769d711 Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Sat, 8 Dec 2018 12:31:19 +0100 Subject: [PATCH] avcodec: add gif parser --- Changelog | 1 + libavcodec/Makefile | 1 + libavcodec/gif_parser.c | 188 ++++++++++++++++++++++++++++++++++++++++ libavcodec/parsers.c | 1 + libavcodec/version.h | 4 +- 5 files changed, 193 insertions(+), 2 deletions(-) create mode 100644 libavcodec/gif_parser.c diff --git a/Changelog b/Changelog index 1f53ff46da..c90f119dc3 100644 --- a/Changelog +++ b/Changelog @@ -10,6 +10,7 @@ version : - truehd_core bitstream filter - dhav demuxer - PCM-DVD encoder +- GIF parser version 4.1: diff --git a/libavcodec/Makefile b/libavcodec/Makefile index 5feadac729..d53b8ff330 100644 --- a/libavcodec/Makefile +++ b/libavcodec/Makefile @@ -1026,6 +1026,7 @@ OBJS-$(CONFIG_DVDSUB_PARSER) += dvdsub_parser.o OBJS-$(CONFIG_FLAC_PARSER) += flac_parser.o flacdata.o flac.o \ vorbis_data.o OBJS-$(CONFIG_G729_PARSER) += g729_parser.o +OBJS-$(CONFIG_GIF_PARSER) += gif_parser.o OBJS-$(CONFIG_GSM_PARSER) += gsm_parser.o OBJS-$(CONFIG_H261_PARSER) += h261_parser.o OBJS-$(CONFIG_H263_PARSER) += h263_parser.o diff --git a/libavcodec/gif_parser.c b/libavcodec/gif_parser.c new file mode 100644 index 0000000000..e88338fd47 --- /dev/null +++ b/libavcodec/gif_parser.c @@ -0,0 +1,188 @@ +/* + * GIF parser + * Copyright (c) 2018 Paul B Mahol + * + * 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 parser + */ + +#include "libavutil/avassert.h" +#include "libavutil/bswap.h" +#include "libavutil/common.h" + +#include "gif.h" +#include "parser.h" + +typedef enum GIFParseStates { + GIF_HEADER = 1, + GIF_EXTENSION, + GIF_EXTENSION_BLOCK, + GIF_IMAGE, + GIF_IMAGE_BLOCK, +} gif_states; + +typedef struct GIFParseContext { + ParseContext pc; + unsigned found_sig; + int found_start; + int found_end; + int index; + int state; + int gct_flag; + int gct_size; + int block_size; + int etype; + int delay; +} GIFParseContext; + +static int gif_find_frame_end(GIFParseContext *g, const uint8_t *buf, + int buf_size, void *logctx) +{ + int index, next = END_NOT_FOUND; + + for (index = 0; index < buf_size; index++) { + if (!g->state) { + if (!memcmp(buf + index, gif87a_sig, 6) || + !memcmp(buf + index, gif89a_sig, 6)) { + g->state = GIF_HEADER; + g->found_sig++; + } else if (buf[index] == GIF_EXTENSION_INTRODUCER) { + g->state = GIF_EXTENSION; + g->found_start = 1; + } else if (buf[index] == GIF_IMAGE_SEPARATOR) { + g->state = GIF_IMAGE; + } else if (buf[index] == GIF_TRAILER) { + g->state = 0; + g->found_end = 1; + g->found_sig = 0; + } else { + g->found_sig = 0; + } + } + + if (g->state == GIF_HEADER) { + if (g->index == 10) { + g->gct_flag = !!(buf[index] & 0x80); + g->gct_size = 3 * (1 << ((buf[index] & 0x07) + 1)); + } + if (g->index >= 12 + g->gct_flag * g->gct_size) { + g->state = 0; + g->index = 0; + g->gct_flag = 0; + g->gct_size = 0; + continue; + } + g->index++; + } else if (g->state == GIF_EXTENSION) { + if (g->found_start && g->found_end && g->found_sig) { + next = index; + g->found_start = 0; + g->found_end = 0; + g->index = 0; + g->gct_flag = 0; + g->gct_size = 0; + g->state = 0; + break; + } + if (g->index == 1) { + g->etype = buf[index]; + } + if (g->index >= 2) { + g->block_size = buf[index]; + g->index = 0; + g->state = GIF_EXTENSION_BLOCK; + continue; + } + g->index++; + } else if (g->state == GIF_IMAGE_BLOCK) { + if (!g->index) + g->block_size = buf[index]; + if (g->index >= g->block_size) { + g->index = 0; + if (!g->block_size) { + g->state = 0; + g->found_end = 1; + } + continue; + } + g->index++; + } else if (g->state == GIF_EXTENSION_BLOCK) { + if (g->etype == GIF_GCE_EXT_LABEL) { + if (g->index == 0) + g->delay = 0; + if (g->index >= 1 && g->index <= 2) { + g->delay |= buf[index] << (8 * (g->index - 1)); + } + } + if (g->index >= g->block_size) { + g->block_size = buf[index]; + g->index = 0; + if (!g->block_size) + g->state = 0; + continue; + } + g->index++; + } else if (g->state == GIF_IMAGE) { + if (g->index == 8) { + g->gct_flag = !!(buf[index] & 0x80); + g->gct_size = 3 * (1 << ((buf[index] & 0x07) + 1)); + } + if (g->index >= 10 + g->gct_flag * g->gct_size) { + g->state = GIF_IMAGE_BLOCK; + g->index = 0; + g->gct_flag = 0; + g->gct_size = 0; + continue; + } + g->index++; + } + } + + return next; +} + +static int gif_parse(AVCodecParserContext *s, AVCodecContext *avctx, + const uint8_t **poutbuf, int *poutbuf_size, + const uint8_t *buf, int buf_size) +{ + GIFParseContext *g = s->priv_data; + int next; + + next = gif_find_frame_end(g, buf, buf_size, avctx); + if (ff_combine_frame(&g->pc, next, &buf, &buf_size) < 0) { + *poutbuf = NULL; + *poutbuf_size = 0; + return buf_size; + } + + s->duration = g->delay; + + *poutbuf = buf; + *poutbuf_size = buf_size; + return next; +} + +AVCodecParser ff_gif_parser = { + .codec_ids = { AV_CODEC_ID_GIF }, + .priv_data_size = sizeof(GIFParseContext), + .parser_parse = gif_parse, + .parser_close = ff_parse_close, +}; diff --git a/libavcodec/parsers.c b/libavcodec/parsers.c index f01cad4c84..eca95787ae 100644 --- a/libavcodec/parsers.c +++ b/libavcodec/parsers.c @@ -41,6 +41,7 @@ extern AVCodecParser ff_dvdsub_parser; extern AVCodecParser ff_dvd_nav_parser; extern AVCodecParser ff_flac_parser; extern AVCodecParser ff_g729_parser; +extern AVCodecParser ff_gif_parser; extern AVCodecParser ff_gsm_parser; extern AVCodecParser ff_h261_parser; extern AVCodecParser ff_h263_parser; diff --git a/libavcodec/version.h b/libavcodec/version.h index 20f9f38fcd..5677a7feba 100644 --- a/libavcodec/version.h +++ b/libavcodec/version.h @@ -28,8 +28,8 @@ #include "libavutil/version.h" #define LIBAVCODEC_VERSION_MAJOR 58 -#define LIBAVCODEC_VERSION_MINOR 41 -#define LIBAVCODEC_VERSION_MICRO 103 +#define LIBAVCODEC_VERSION_MINOR 42 +#define LIBAVCODEC_VERSION_MICRO 100 #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \ LIBAVCODEC_VERSION_MINOR, \