diff options
| -rw-r--r-- | doc/general.texi | 2 | ||||
| -rw-r--r-- | libavformat/Makefile | 1 | ||||
| -rw-r--r-- | libavformat/allformats.c | 2 | ||||
| -rwxr-xr-x | libavformat/gifdec.c | 292 | ||||
| -rw-r--r-- | libavformat/version.h | 2 |
5 files changed, 296 insertions, 3 deletions
diff --git a/doc/general.texi b/doc/general.texi index 762b94eff9..9a5dfcdf33 100644 --- a/doc/general.texi +++ b/doc/general.texi @@ -215,7 +215,7 @@ library: @item G.723.1 @tab X @tab X @item G.729 BIT @tab X @tab X @item G.729 raw @tab @tab X -@item GIF Animation @tab X @tab +@item GIF Animation @tab X @tab X @item GXF @tab X @tab X @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers. diff --git a/libavformat/Makefile b/libavformat/Makefile index 3aa3f4f10b..bc4e076823 100644 --- a/libavformat/Makefile +++ b/libavformat/Makefile @@ -113,6 +113,7 @@ OBJS-$(CONFIG_FOURXM_DEMUXER) += 4xm.o OBJS-$(CONFIG_FRAMECRC_MUXER) += framecrcenc.o framehash.o OBJS-$(CONFIG_FRAMEMD5_MUXER) += md5enc.o framehash.o OBJS-$(CONFIG_GIF_MUXER) += gif.o +OBJS-$(CONFIG_GIF_DEMUXER) += gifdec.o OBJS-$(CONFIG_GSM_DEMUXER) += gsmdec.o OBJS-$(CONFIG_GXF_DEMUXER) += gxf.o OBJS-$(CONFIG_GXF_MUXER) += gxfenc.o audiointerleave.o diff --git a/libavformat/allformats.c b/libavformat/allformats.c index e183d4013c..2c32cc28fd 100644 --- a/libavformat/allformats.c +++ b/libavformat/allformats.c @@ -111,7 +111,7 @@ void av_register_all(void) REGISTER_MUXDEMUX (G722, g722); REGISTER_MUXDEMUX (G723_1, g723_1); REGISTER_DEMUXER (G729, g729); - REGISTER_MUXER (GIF, gif); + REGISTER_MUXDEMUX (GIF, gif); REGISTER_DEMUXER (GSM, gsm); REGISTER_MUXDEMUX (GXF, gxf); REGISTER_MUXDEMUX (H261, h261); diff --git a/libavformat/gifdec.c b/libavformat/gifdec.c new file mode 100755 index 0000000000..f566239098 --- /dev/null +++ b/libavformat/gifdec.c @@ -0,0 +1,292 @@ +/* + * GIF demuxer + * Copyright (c) 2012 Vitaliy E Sugrobov + * + * 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 demuxer. + */ + +#include "avformat.h" +#include "libavutil/intreadwrite.h" +#include "libavutil/opt.h" +#include "internal.h" +#include "libavcodec/gif.h" + +typedef struct GIFDemuxContext { + const AVClass *class; + uint32_t width; + uint32_t height; + /** + * Time span in hundredths of second before + * the next frame should be drawn on screen. + */ + int delay; + /** + * Minimum allowed delay between frames in hundredths of + * second. Values below this threshold considered to be + * invalid and set to value of default_delay. + */ + int min_delay; + int default_delay; + int total_duration; ///< In hundredths of second. + int frame_idx; +} GIFDemuxContext; + +/** + * Major web browsers display gifs at ~10-15fps when rate + * is not explicitly set or have too low values. We assume default rate to be 10. + * Default delay = 100hundredths of second / 10fps = 10hos per frame. + */ +#define GIF_DEFAULT_DELAY 10 +/** + * By default delay values less than this threshold considered to be invalid. + */ +#define GIF_MIN_DELAY 2 + +static int gif_probe(AVProbeData *p) +{ + /* check magick */ + if (memcmp(p->buf, gif87a_sig, 6) && memcmp(p->buf, gif89a_sig, 6)) + return 0; + + /* width or height contains zero? */ + if (!AV_RL16(&p->buf[6]) || !AV_RL16(&p->buf[8])) + return 0; + + return AVPROBE_SCORE_MAX; +} + +static int gif_read_header(AVFormatContext *s) +{ + GIFDemuxContext *gdc = s->priv_data; + AVIOContext *pb = s->pb; + AVStream *st; + int ret; + + /* skip 6-byte magick */ + if ((ret = avio_skip(pb, 6)) < 0) + return ret; + + gdc->delay = gdc->default_delay; + gdc->width = avio_rl16(pb); + gdc->height = avio_rl16(pb); + + if (gdc->width == 0 || gdc->height == 0) + return AVERROR_INVALIDDATA; + + st = avformat_new_stream(s, NULL); + if (!st) + return AVERROR(ENOMEM); + + /* GIF format operates with time in "hundredths of second", + * therefore timebase is 1/100 */ + avpriv_set_pts_info(st, 64, 1, 100); + st->codec->codec_type = AVMEDIA_TYPE_VIDEO; + st->codec->codec_id = AV_CODEC_ID_GIF; + st->codec->width = gdc->width; + st->codec->height = gdc->height; + + /* jump to start because gif decoder needs header data too */ + if (avio_seek(pb, 0, SEEK_SET) != 0) + return AVERROR(EIO); + + return 0; +} + +static int gif_skip_subblocks(AVIOContext *pb) +{ + int sb_size, ret = 0; + + while (0x00 != (sb_size = avio_r8(pb))) { + if ((ret = avio_skip(pb, sb_size)) < 0) + return ret; + } + + return ret; +} + +static int gif_read_ext(AVFormatContext *s) +{ + GIFDemuxContext *gdc = s->priv_data; + AVIOContext *pb = s->pb; + int sb_size, ext_label = avio_r8(pb); + int ret; + + if (ext_label == GIF_GCE_EXT_LABEL) { + if ((sb_size = avio_r8(pb)) < 4) { + av_log(s, AV_LOG_FATAL, "Graphic Control Extension block's size less than 4.\n"); + return AVERROR_INVALIDDATA; + } + + /* skip packed fields */ + if ((ret = avio_skip(pb, 1)) < 0) + return ret; + + gdc->delay = avio_rl16(pb); + + if (gdc->delay < gdc->min_delay) + gdc->delay = gdc->default_delay; + + /* skip the rest of the Graphic Control Extension block */ + if ((ret = avio_skip(pb, sb_size - 3)) < 0 ) + return ret; + } + + if ((ret = gif_skip_subblocks(pb)) < 0) + return ret; + + return 0; +} + +static int gif_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + GIFDemuxContext *gdc = s->priv_data; + AVIOContext *pb = s->pb; + int packed_fields, block_label, ct_size, + keyframe, frame_parsed = 0, ret; + int64_t frame_start = avio_tell(pb), frame_end; + unsigned char buf[6]; + + if ((ret = avio_read(pb, buf, 6)) == 6) { + keyframe = memcmp(buf, gif87a_sig, 6) == 0 || + memcmp(buf, gif89a_sig, 6) == 0; + } else if (ret < 0) { + return ret; + } else { + keyframe = 0; + } + + if (keyframe) { + /* skip 2 bytes of width and 2 of height */ + if ((ret = avio_skip(pb, 4)) < 0) + return ret; + + packed_fields = avio_r8(pb); + + /* skip 1 byte of Background Color Index and 1 byte of Pixel Aspect Ratio */ + if ((ret = avio_skip(pb, 2)) < 0) + return ret; + + /* glogal color table presence */ + if (packed_fields & 0x80) { + ct_size = 3 * (1 << ((packed_fields & 0x07) + 1)); + + if ((ret = avio_skip(pb, ct_size)) < 0) + return ret; + } + + gdc->total_duration = 0; + gdc->frame_idx = 0; + } else { + avio_seek(pb, -ret, SEEK_CUR); + ret = AVERROR_EOF; + } + + while (GIF_TRAILER != (block_label = avio_r8(pb)) && !url_feof(pb)) { + if (block_label == GIF_EXTENSION_INTRODUCER) { + if ((ret = gif_read_ext (s)) < 0 ) + return ret; + } else if (block_label == GIF_IMAGE_SEPARATOR) { + /* skip to last byte of Image Descriptor header */ + if ((ret = avio_skip(pb, 8)) < 0) + return ret; + + packed_fields = avio_r8(pb); + + /* local color table presence */ + if (packed_fields & 0x80) { + ct_size = 3 * (1 << ((packed_fields & 0x07) + 1)); + + if ((ret = avio_skip(pb, ct_size)) < 0) + return ret; + } + + /* read LZW Minimum Code Size */ + if (avio_r8(pb) < 1) { + av_log(s, AV_LOG_ERROR, "lzw minimum code size must be >= 1\n"); + return AVERROR_INVALIDDATA; + } + + if ((ret = gif_skip_subblocks(pb)) < 0) + return ret; + + frame_end = avio_tell(pb); + + if (avio_seek(pb, frame_start, SEEK_SET) != frame_start) + return AVERROR(EIO); + + ret = av_get_packet(pb, pkt, frame_end - frame_start); + if (ret < 0) + return ret; + + if (keyframe) + pkt->flags |= AV_PKT_FLAG_KEY; + + pkt->stream_index = 0; + pkt->pts = gdc->total_duration; + gdc->total_duration += gdc->delay; + pkt->duration = gdc->delay; + pkt->dts = gdc->frame_idx; + + /* Graphic Control Extension's scope is single frame. + * Remove its influence. */ + gdc->delay = gdc->default_delay; + gdc->frame_idx++; + frame_parsed = 1; + + break; + } else { + av_log(s, AV_LOG_ERROR, "invalid block label\n"); + return AVERROR_INVALIDDATA; + } + } + + if (ret >= 0 && !frame_parsed) { + /* This might happen when there is no image block + * between extension blocks and GIF_TRAILER or EOF */ + return AVERROR_EOF; + } else + return ret; +} + +static const AVOption options[] = { + { "min_delay" , "minimum valid delay between frames (in hundredths of second)", offsetof(GIFDemuxContext, min_delay) , AV_OPT_TYPE_INT, {.i64 = GIF_MIN_DELAY} , 0, 100 * 60, AV_OPT_FLAG_DECODING_PARAM }, + { "default_delay", "default delay between frames (in hundredths of second)" , offsetof(GIFDemuxContext, default_delay), AV_OPT_TYPE_INT, {.i64 = GIF_DEFAULT_DELAY}, 0, 100 * 60, AV_OPT_FLAG_DECODING_PARAM }, + { NULL }, +}; + +static const AVClass demuxer_class = { + .class_name = "GIF demuxer", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, + .category = AV_CLASS_CATEGORY_DEMUXER, +}; + +AVInputFormat ff_gif_demuxer = { + .name = "gif", + .long_name = NULL_IF_CONFIG_SMALL("CompuServe Graphics Interchange Format (GIF)"), + .priv_data_size = sizeof(GIFDemuxContext), + .read_probe = gif_probe, + .read_header = gif_read_header, + .read_packet = gif_read_packet, + .priv_class = &demuxer_class, +}; diff --git a/libavformat/version.h b/libavformat/version.h index e0e6e4b7f0..4bea059735 100644 --- a/libavformat/version.h +++ b/libavformat/version.h @@ -30,7 +30,7 @@ #include "libavutil/avutil.h" #define LIBAVFORMAT_VERSION_MAJOR 54 -#define LIBAVFORMAT_VERSION_MINOR 40 +#define LIBAVFORMAT_VERSION_MINOR 41 #define LIBAVFORMAT_VERSION_MICRO 100 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \ |