/* * Animated WebP demuxer * Copyright (c) 2020 Pexeso Inc. * Copyright (c) 2026 Ramiro Polla * * 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 * Animated WebP demuxer. */ #include "avio_internal.h" #include "demux.h" #include "avformat.h" #include "internal.h" #include "libavutil/intreadwrite.h" #include "libavutil/mem.h" #include "libavutil/opt.h" #define VP8X_FLAG_ANIMATION 0x02 #define VP8X_FLAG_XMP_METADATA 0x04 #define VP8X_FLAG_EXIF_METADATA 0x08 #define VP8X_FLAG_ALPHA 0x10 #define VP8X_FLAG_ICC 0x20 typedef struct WebPAnimDemuxContext { const AVClass *class; /** * Minimum allowed delay between frames in milliseconds. * Values below this threshold are considered to be invalid * and set to value of default_delay. */ int min_delay; int max_delay; int default_delay; /* * loop options */ int ignore_loop; ///< ignore loop setting int loop_count; ///< number of times to loop the animation int cur_loop; ///< current loop counter /* * variables for the key frame detection */ int cur_frame; ///< number of frames of the current animation file int vp8x_flags; int has_iccp; int has_exif; int has_anim; int has_xmp; int usebgcolor; int64_t first_anmf_offset; } WebPAnimDemuxContext; /** * Major web browsers display WebPs at ~10-15fps when rate is not * explicitly set or have too low values. We assume default rate to be 10. * Default delay = 1000 microseconds / 10fps = 100 milliseconds per frame. */ #define WEBP_DEFAULT_DELAY 100 /** * By default delay values less than this threshold considered to be invalid. */ #define WEBP_MIN_DELAY 10 static int webp_anim_probe(const AVProbeData *p) { const uint8_t *b = p->buf; if (AV_RL32(b) == MKTAG('R', 'I', 'F', 'F') && AV_RL32(b + 8) == MKTAG('W', 'E', 'B', 'P') && AV_RL32(b + 12) == MKTAG('V', 'P', '8', 'X') && AV_RL32(b + 16) == 10 && (b[20] & VP8X_FLAG_ANIMATION)) return AVPROBE_SCORE_MAX; return 0; } static int webp_anim_read_header(AVFormatContext *s) { WebPAnimDemuxContext *ctx = s->priv_data; AVIOContext *pb = s->pb; int ret; /* Check for signature. */ if (avio_rl32(pb) != MKTAG('R', 'I', 'F', 'F')) return AVERROR_INVALIDDATA; avio_skip(pb, 4); /* file size */ if (avio_rl32(pb) != MKTAG('W', 'E', 'B', 'P')) return AVERROR_INVALIDDATA; /* VP8X must be first chunk */ if (avio_rl32(pb) != MKTAG('V', 'P', '8', 'X') || avio_rl32(pb) != 10 /* chunk size */) return AVERROR_INVALIDDATA; ctx->vp8x_flags = avio_r8(pb); if (!(ctx->vp8x_flags & VP8X_FLAG_ANIMATION)) return AVERROR_INVALIDDATA; avio_skip(pb, 3); AVStream *st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); avpriv_set_pts_info(st, 64, 1, 1000); st->codecpar->format = AV_PIX_FMT_ARGB; st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; st->codecpar->codec_id = AV_CODEC_ID_WEBP_ANIM; st->codecpar->width = avio_rl24(pb) + 1; st->codecpar->height = avio_rl24(pb) + 1; st->start_time = 0; int explode = (s->error_recognition & AV_EF_EXPLODE); int loglevel = explode ? AV_LOG_ERROR : AV_LOG_WARNING; while (1) { int64_t offset = avio_tell(pb); uint32_t fourcc = avio_rl32(pb); uint32_t size = avio_rl32(pb); av_log(s, AV_LOG_DEBUG, "Chunk %s of size %u at offset %" PRId64 "\n", av_fourcc2str(fourcc), size, offset); if (size == UINT32_MAX) return AVERROR_INVALIDDATA; size += size & 1; if (avio_feof(pb)) break; switch (fourcc) { case MKTAG('I', 'C', 'C', 'P'): if (ctx->has_iccp) { av_log(s, loglevel, "Extra ICCP chunk found\n"); if (explode) return AVERROR_INVALIDDATA; avio_skip(pb, size); } else { if (!(ctx->vp8x_flags & VP8X_FLAG_ICC)) { av_log(s, loglevel, "ICCP chunk present, but ICC Profile bit not set in the VP8X header\n"); if (explode) return AVERROR_INVALIDDATA; } AVPacketSideData *sd = av_packet_side_data_new(&st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data, AV_PKT_DATA_ICC_PROFILE, size, 0); if (!sd) return AVERROR(ENOMEM); ret = ffio_read_size(pb, sd->data, size); if (ret < 0) { av_packet_side_data_remove(st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data, AV_PKT_DATA_ICC_PROFILE); return ret; } ctx->has_iccp = 1; } break; case MKTAG('A', 'N', 'I', 'M'): if (ctx->has_anim) { av_log(s, loglevel, "Extra ANIM chunk found\n"); if (explode) return AVERROR_INVALIDDATA; avio_skip(pb, size); } else { if (size != 6) return AVERROR_INVALIDDATA; uint32_t bg_color = avio_rb32(pb); ctx->loop_count = avio_rl16(pb); if (ctx->usebgcolor) { st->codecpar->extradata = av_mallocz(4 + AV_INPUT_BUFFER_PADDING_SIZE); if (!st->codecpar->extradata) return AVERROR(ENOMEM); AV_WB32(st->codecpar->extradata, bg_color); st->codecpar->extradata_size = 4; } av_log(s, AV_LOG_DEBUG, "ANIM: background BGRA 0x%08x loop count %d\n", bg_color, ctx->loop_count); ctx->has_anim = 1; } break; case MKTAG('A', 'N', 'M', 'F'): if (!ctx->has_anim) { av_log(s, loglevel, "ANMF chunk present, but no previous ANIM chunk found\n"); if (explode) return AVERROR_INVALIDDATA; ctx->loop_count = 1; } else if (!ctx->ignore_loop && ctx->loop_count != 1) { int64_t file_size = avio_size(pb); if (file_size < 0 || offset < 0 || (ret = ffio_ensure_seekback(pb, file_size - offset)) < 0) { av_log(s, AV_LOG_WARNING, "Could not ensure seekback, will not loop\n"); ctx->loop_count = 1; } } ctx->first_anmf_offset = offset; ret = avio_seek(pb, -8, SEEK_CUR); if (ret < 0) return ret; return 0; default: av_log(s, AV_LOG_WARNING, "Skipping chunk: %s\n", av_fourcc2str(fourcc)); avio_skip(pb, size); break; } } return AVERROR_INVALIDDATA; } static int webp_anim_read_packet(AVFormatContext *s, AVPacket *pkt) { WebPAnimDemuxContext *ctx = s->priv_data; AVIOContext *pb = s->pb; int ret; int explode = (s->error_recognition & AV_EF_EXPLODE); int loglevel = explode ? AV_LOG_ERROR : AV_LOG_WARNING; while (1) { int64_t offset = avio_tell(pb); uint32_t fourcc = avio_rl32(pb); uint32_t size = avio_rl32(pb); if (size == UINT32_MAX) return AVERROR_INVALIDDATA; size += size & 1; if (avio_feof(pb)) { if (!ctx->ignore_loop && (ctx->loop_count == 0 || ++ctx->cur_loop < ctx->loop_count)) { ctx->cur_frame = 0; ret = avio_seek(pb, ctx->first_anmf_offset, SEEK_SET); if (ret < 0) return ret; continue; } break; } av_log(s, AV_LOG_DEBUG, "Chunk %s of size %u at offset %" PRId64 "\n", av_fourcc2str(fourcc), size, offset); switch (fourcc) { case MKTAG('A', 'N', 'M', 'F'): if (size < 16) return AVERROR_INVALIDDATA; ret = av_get_packet(pb, pkt, size); if (ret < 0) return ret; if (!ctx->cur_frame++) pkt->flags |= AV_PKT_FLAG_KEY; pkt->pts = AV_NOPTS_VALUE; pkt->dts = AV_NOPTS_VALUE; uint32_t duration = AV_RL24(pkt->data + 12); if (duration <= ctx->min_delay) duration = ctx->default_delay; pkt->duration = FFMIN(duration, ctx->max_delay); return ret; case MKTAG('E', 'X', 'I', 'F'): if (ctx->has_exif) { av_log(s, loglevel, "Extra EXIF chunk found\n"); if (explode) return AVERROR_INVALIDDATA; avio_skip(pb, size); } else { if (!(ctx->vp8x_flags & VP8X_FLAG_EXIF_METADATA)) { av_log(s, loglevel, "EXIF chunk present, but EXIF bit not set in the VP8X header\n"); if (explode) return AVERROR_INVALIDDATA; } AVStream *st = s->streams[0]; AVPacketSideData *sd = av_packet_side_data_new(&st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data, AV_PKT_DATA_EXIF, size, 0); if (!sd) return AVERROR(ENOMEM); ret = ffio_read_size(pb, sd->data, size); if (ret < 0) { av_packet_side_data_remove(st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data, AV_PKT_DATA_EXIF); return ret; } ctx->has_exif = 1; } break; case MKTAG('X', 'M', 'P', ' '): if (ctx->has_xmp) { av_log(s, loglevel, "Extra XMP chunk found\n"); if (explode) return AVERROR_INVALIDDATA; avio_skip(pb, size); } else { if (!(ctx->vp8x_flags & VP8X_FLAG_XMP_METADATA)) { av_log(s, loglevel, "XMP chunk present, but XMP bit not set in the VP8X header\n"); if (explode) return AVERROR_INVALIDDATA; } uint8_t *xmp = av_malloc(size + 1); if (!xmp) return AVERROR(ENOMEM); ret = ffio_read_size(pb, xmp, size); if (ret < 0) { av_free(xmp); return ret; } xmp[size] = '\0'; av_dict_set(&s->metadata, "xmp", xmp, AV_DICT_DONT_STRDUP_VAL); ctx->has_xmp = 1; } break; default: av_log(s, AV_LOG_WARNING, "Skipping chunk: %s\n", av_fourcc2str(fourcc)); avio_skip(pb, size); break; } } return AVERROR_EOF; } static const AVOption options[] = { { "min_delay", "minimum valid delay between frames (in milliseconds)", offsetof(WebPAnimDemuxContext, min_delay), AV_OPT_TYPE_INT, {.i64 = WEBP_MIN_DELAY}, 0, 1000 * 60, AV_OPT_FLAG_DECODING_PARAM }, { "max_webp_delay", "maximum valid delay between frames (in milliseconds)", offsetof(WebPAnimDemuxContext, max_delay), AV_OPT_TYPE_INT, {.i64 = 0xffffff}, 0, 0xffffff, AV_OPT_FLAG_DECODING_PARAM }, { "default_delay", "default delay between frames (in milliseconds)", offsetof(WebPAnimDemuxContext, default_delay), AV_OPT_TYPE_INT, {.i64 = WEBP_DEFAULT_DELAY}, 0, 1000 * 60, AV_OPT_FLAG_DECODING_PARAM }, { "ignore_loop", "ignore loop setting", offsetof(WebPAnimDemuxContext, ignore_loop), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_DECODING_PARAM }, { "usebgcolor", "use background color from ANIM chunk", offsetof(WebPAnimDemuxContext, usebgcolor), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM }, { NULL }, }; static const AVClass demuxer_class = { .class_name = "Animated WebP demuxer", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, .category = AV_CLASS_CATEGORY_DEMUXER, }; const FFInputFormat ff_webp_anim_demuxer = { .p.name = "webp_anim", .p.long_name = NULL_IF_CONFIG_SMALL("Animated WebP"), .p.flags = AVFMT_GENERIC_INDEX, .p.priv_class = &demuxer_class, .priv_data_size = sizeof(WebPAnimDemuxContext), .read_probe = webp_anim_probe, .read_header = webp_anim_read_header, .read_packet = webp_anim_read_packet, };