| /* | |
| * APNG demuxer | |
| * Copyright (c) 2014 Benoit Fouet | |
| * | |
| * 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 | |
| * APNG demuxer. | |
| * @see https://wiki.mozilla.org/APNG_Specification | |
| * @see http://www.w3.org/TR/PNG | |
| */ | |
| #include "avformat.h" | |
| #include "avio_internal.h" | |
| #include "demux.h" | |
| #include "internal.h" | |
| #include "libavutil/imgutils.h" | |
| #include "libavutil/intreadwrite.h" | |
| #include "libavutil/opt.h" | |
| #include "libavcodec/apng.h" | |
| #include "libavcodec/png.h" | |
| #include "libavcodec/bytestream.h" | |
| #define DEFAULT_APNG_FPS 15 | |
| typedef struct APNGDemuxContext { | |
| const AVClass *class; | |
| int max_fps; | |
| int default_fps; | |
| int pkt_duration; | |
| int is_key_frame; | |
| /* | |
| * loop options | |
| */ | |
| int ignore_loop; | |
| uint32_t num_frames; | |
| uint32_t num_play; | |
| uint32_t cur_loop; | |
| } APNGDemuxContext; | |
| /* | |
| * To be a valid APNG file, we mandate, in this order: | |
| * PNGSIG | |
| * IHDR | |
| * ... | |
| * acTL | |
| * ... | |
| * IDAT | |
| */ | |
| static int apng_probe(const AVProbeData *p) | |
| { | |
| GetByteContext gb; | |
| int state = 0; | |
| uint32_t len, tag; | |
| bytestream2_init(&gb, p->buf, p->buf_size); | |
| if (bytestream2_get_be64(&gb) != PNGSIG) | |
| return 0; | |
| for (;;) { | |
| len = bytestream2_get_be32(&gb); | |
| if (len > 0x7fffffff) | |
| return 0; | |
| tag = bytestream2_get_le32(&gb); | |
| /* we don't check IDAT size, as this is the last tag | |
| * we check, and it may be larger than the probe buffer */ | |
| if (tag != MKTAG('I', 'D', 'A', 'T') && | |
| len + 4 > bytestream2_get_bytes_left(&gb)) | |
| return 0; | |
| switch (tag) { | |
| case MKTAG('I', 'H', 'D', 'R'): | |
| if (len != 13) | |
| return 0; | |
| if (av_image_check_size(bytestream2_get_be32(&gb), bytestream2_get_be32(&gb), 0, NULL)) | |
| return 0; | |
| bytestream2_skip(&gb, 9); | |
| state++; | |
| break; | |
| case MKTAG('a', 'c', 'T', 'L'): | |
| if (state != 1 || | |
| len != 8 || | |
| bytestream2_get_be32(&gb) == 0) /* 0 is not a valid value for number of frames */ | |
| return 0; | |
| bytestream2_skip(&gb, 8); | |
| state++; | |
| break; | |
| case MKTAG('I', 'D', 'A', 'T'): | |
| if (state != 2) | |
| return 0; | |
| goto end; | |
| default: | |
| /* skip other tags */ | |
| bytestream2_skip(&gb, len + 4); | |
| break; | |
| } | |
| } | |
| end: | |
| return AVPROBE_SCORE_MAX; | |
| } | |
| static int append_extradata(AVCodecParameters *par, AVIOContext *pb, int len) | |
| { | |
| int previous_size = par->extradata_size; | |
| int new_size, ret; | |
| uint8_t *new_extradata; | |
| if (len > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE - previous_size) | |
| return AVERROR_INVALIDDATA; | |
| new_size = previous_size + len; | |
| new_extradata = av_realloc(par->extradata, new_size + AV_INPUT_BUFFER_PADDING_SIZE); | |
| if (!new_extradata) | |
| return AVERROR(ENOMEM); | |
| memset(new_extradata + new_size, 0, AV_INPUT_BUFFER_PADDING_SIZE); | |
| par->extradata = new_extradata; | |
| par->extradata_size = new_size; | |
| if ((ret = ffio_read_size(pb, par->extradata + previous_size, len)) < 0) | |
| return ret; | |
| return previous_size; | |
| } | |
| static int apng_read_header(AVFormatContext *s) | |
| { | |
| APNGDemuxContext *ctx = s->priv_data; | |
| AVIOContext *pb = s->pb; | |
| uint32_t len, tag; | |
| AVStream *st; | |
| int acTL_found = 0; | |
| int64_t ret; | |
| /* verify PNGSIG */ | |
| if (avio_rb64(pb) != PNGSIG) | |
| return AVERROR_INVALIDDATA; | |
| /* parse IHDR (must be first chunk) */ | |
| len = avio_rb32(pb); | |
| tag = avio_rl32(pb); | |
| if (len != 13 || tag != MKTAG('I', 'H', 'D', 'R')) | |
| return AVERROR_INVALIDDATA; | |
| st = avformat_new_stream(s, NULL); | |
| if (!st) | |
| return AVERROR(ENOMEM); | |
| /* set the timebase to something large enough (1/100,000 of second) | |
| * to hopefully cope with all sane frame durations */ | |
| avpriv_set_pts_info(st, 64, 1, 100000); | |
| st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; | |
| st->codecpar->codec_id = AV_CODEC_ID_APNG; | |
| st->codecpar->width = avio_rb32(pb); | |
| st->codecpar->height = avio_rb32(pb); | |
| if ((ret = av_image_check_size(st->codecpar->width, st->codecpar->height, 0, s)) < 0) | |
| return ret; | |
| /* extradata will contain every chunk up to the first fcTL (excluded) */ | |
| ret = ff_alloc_extradata(st->codecpar, len + 12); | |
| if (ret < 0) | |
| return ret; | |
| AV_WB32(st->codecpar->extradata, len); | |
| AV_WL32(st->codecpar->extradata+4, tag); | |
| AV_WB32(st->codecpar->extradata+8, st->codecpar->width); | |
| AV_WB32(st->codecpar->extradata+12, st->codecpar->height); | |
| if ((ret = ffio_read_size(pb, st->codecpar->extradata + 16, 9)) < 0) | |
| return ret; | |
| while (1) { | |
| if (acTL_found && ctx->num_play != 1) { | |
| int64_t size = avio_size(pb); | |
| int64_t offset = avio_tell(pb); | |
| if (size < 0) { | |
| return size; | |
| } else if (offset < 0) { | |
| return offset; | |
| } else if ((ret = ffio_ensure_seekback(pb, size - offset)) < 0) { | |
| av_log(s, AV_LOG_WARNING, "Could not ensure seekback, will not loop\n"); | |
| ctx->num_play = 1; | |
| } | |
| } | |
| if ((ctx->num_play == 1 || !acTL_found) && | |
| ((ret = ffio_ensure_seekback(pb, 4 /* len */ + 4 /* tag */)) < 0)) | |
| return ret; | |
| len = avio_rb32(pb); | |
| if (len > INT_MAX - 12) | |
| return AVERROR_INVALIDDATA; | |
| tag = avio_rl32(pb); | |
| switch (tag) { | |
| case MKTAG('a', 'c', 'T', 'L'): | |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 || | |
| (ret = append_extradata(st->codecpar, pb, len + 12)) < 0) | |
| return ret; | |
| acTL_found = 1; | |
| ctx->num_frames = AV_RB32(st->codecpar->extradata + ret + 8); | |
| ctx->num_play = AV_RB32(st->codecpar->extradata + ret + 12); | |
| av_log(s, AV_LOG_DEBUG, "num_frames: %"PRIu32", num_play: %"PRIu32"\n", | |
| ctx->num_frames, ctx->num_play); | |
| break; | |
| case MKTAG('f', 'c', 'T', 'L'): | |
| if (!acTL_found || len != APNG_FCTL_CHUNK_SIZE) { | |
| return AVERROR_INVALIDDATA; | |
| } | |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0) | |
| return ret; | |
| return 0; | |
| default: | |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 || | |
| (ret = append_extradata(st->codecpar, pb, len + 12)) < 0) | |
| return ret; | |
| } | |
| } | |
| } | |
| static int decode_fctl_chunk(AVFormatContext *s, APNGDemuxContext *ctx, AVPacket *pkt) | |
| { | |
| uint32_t sequence_number, width, height, x_offset, y_offset; | |
| uint16_t delay_num, delay_den; | |
| uint8_t dispose_op, blend_op; | |
| sequence_number = avio_rb32(s->pb); | |
| width = avio_rb32(s->pb); | |
| height = avio_rb32(s->pb); | |
| x_offset = avio_rb32(s->pb); | |
| y_offset = avio_rb32(s->pb); | |
| delay_num = avio_rb16(s->pb); | |
| delay_den = avio_rb16(s->pb); | |
| dispose_op = avio_r8(s->pb); | |
| blend_op = avio_r8(s->pb); | |
| avio_skip(s->pb, 4); /* crc */ | |
| /* default is hundredths of seconds */ | |
| if (!delay_den) | |
| delay_den = 100; | |
| if (!delay_num || (ctx->max_fps && delay_den / delay_num > ctx->max_fps)) { | |
| delay_num = 1; | |
| delay_den = ctx->default_fps; | |
| } | |
| ctx->pkt_duration = av_rescale_q(delay_num, | |
| (AVRational){ 1, delay_den }, | |
| s->streams[0]->time_base); | |
| av_log(s, AV_LOG_DEBUG, "%s: " | |
| "sequence_number: %"PRId32", " | |
| "width: %"PRIu32", " | |
| "height: %"PRIu32", " | |
| "x_offset: %"PRIu32", " | |
| "y_offset: %"PRIu32", " | |
| "delay_num: %"PRIu16", " | |
| "delay_den: %"PRIu16", " | |
| "dispose_op: %d, " | |
| "blend_op: %d\n", | |
| __func__, | |
| sequence_number, | |
| width, | |
| height, | |
| x_offset, | |
| y_offset, | |
| delay_num, | |
| delay_den, | |
| dispose_op, | |
| blend_op); | |
| if (width != s->streams[0]->codecpar->width || | |
| height != s->streams[0]->codecpar->height || | |
| x_offset != 0 || | |
| y_offset != 0) { | |
| if (sequence_number == 0 || | |
| x_offset >= s->streams[0]->codecpar->width || | |
| width > s->streams[0]->codecpar->width - x_offset || | |
| y_offset >= s->streams[0]->codecpar->height || | |
| height > s->streams[0]->codecpar->height - y_offset) | |
| return AVERROR_INVALIDDATA; | |
| ctx->is_key_frame = 0; | |
| } else { | |
| if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS) | |
| dispose_op = APNG_DISPOSE_OP_BACKGROUND; | |
| ctx->is_key_frame = dispose_op == APNG_DISPOSE_OP_BACKGROUND || | |
| blend_op == APNG_BLEND_OP_SOURCE; | |
| } | |
| return 0; | |
| } | |
| static int apng_read_packet(AVFormatContext *s, AVPacket *pkt) | |
| { | |
| APNGDemuxContext *ctx = s->priv_data; | |
| int64_t ret; | |
| int64_t size; | |
| AVIOContext *pb = s->pb; | |
| uint32_t len, tag; | |
| /* | |
| * fcTL chunk length, in bytes: | |
| * 4 (length) | |
| * 4 (tag) | |
| * 26 (actual chunk) | |
| * 4 (crc) bytes | |
| * and needed next: | |
| * 4 (length) | |
| * 4 (tag (must be fdAT or IDAT)) | |
| */ | |
| /* if num_play is not 1, then the seekback is already guaranteed */ | |
| if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 46)) < 0) | |
| return ret; | |
| len = avio_rb32(pb); | |
| tag = avio_rl32(pb); | |
| if (avio_feof(pb)) | |
| return AVERROR_EOF; | |
| switch (tag) { | |
| case MKTAG('f', 'c', 'T', 'L'): | |
| if (len != APNG_FCTL_CHUNK_SIZE) | |
| return AVERROR_INVALIDDATA; | |
| if ((ret = decode_fctl_chunk(s, ctx, pkt)) < 0) | |
| return ret; | |
| /* fcTL must precede fdAT or IDAT */ | |
| len = avio_rb32(pb); | |
| tag = avio_rl32(pb); | |
| if (len > 0x7fffffff || | |
| tag != MKTAG('f', 'd', 'A', 'T') && | |
| tag != MKTAG('I', 'D', 'A', 'T')) | |
| return AVERROR_INVALIDDATA; | |
| size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */; | |
| if (size > INT_MAX) | |
| return AVERROR(EINVAL); | |
| if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0 || | |
| (ret = av_append_packet(pb, pkt, size)) < 0) | |
| return ret; | |
| if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0) | |
| return ret; | |
| len = avio_rb32(pb); | |
| tag = avio_rl32(pb); | |
| while (tag && | |
| tag != MKTAG('f', 'c', 'T', 'L') && | |
| tag != MKTAG('I', 'E', 'N', 'D')) { | |
| if (len > 0x7fffffff) | |
| return AVERROR_INVALIDDATA; | |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 || | |
| (ret = av_append_packet(pb, pkt, len + 12)) < 0) | |
| return ret; | |
| if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0) | |
| return ret; | |
| len = avio_rb32(pb); | |
| tag = avio_rl32(pb); | |
| } | |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0) | |
| return ret; | |
| if (ctx->is_key_frame) | |
| pkt->flags |= AV_PKT_FLAG_KEY; | |
| pkt->pts = pkt->dts = AV_NOPTS_VALUE; | |
| pkt->duration = ctx->pkt_duration; | |
| return ret; | |
| case MKTAG('I', 'E', 'N', 'D'): | |
| ctx->cur_loop++; | |
| if (ctx->ignore_loop || ctx->num_play >= 1 && ctx->cur_loop == ctx->num_play) { | |
| avio_seek(pb, -8, SEEK_CUR); | |
| return AVERROR_EOF; | |
| } | |
| if ((ret = avio_seek(pb, s->streams[0]->codecpar->extradata_size + 8, SEEK_SET)) < 0) | |
| return ret; | |
| return 0; | |
| default: | |
| avpriv_request_sample(s, "In-stream tag=%s (0x%08"PRIX32") len=%"PRIu32, | |
| av_fourcc2str(tag), tag, len); | |
| avio_skip(pb, len + 4); | |
| } | |
| /* Handle the unsupported yet cases */ | |
| return AVERROR_PATCHWELCOME; | |
| } | |
| static const AVOption options[] = { | |
| { "ignore_loop", "ignore loop setting" , offsetof(APNGDemuxContext, ignore_loop), | |
| AV_OPT_TYPE_BOOL, { .i64 = 1 } , 0, 1 , AV_OPT_FLAG_DECODING_PARAM }, | |
| { "max_fps" , "maximum framerate (0 is no limit)" , offsetof(APNGDemuxContext, max_fps), | |
| AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }, | |
| { "default_fps", "default framerate (0 is as fast as possible)", offsetof(APNGDemuxContext, default_fps), | |
| AV_OPT_TYPE_INT, { .i64 = DEFAULT_APNG_FPS }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }, | |
| { NULL }, | |
| }; | |
| static const AVClass demuxer_class = { | |
| .class_name = "APNG demuxer", | |
| .item_name = av_default_item_name, | |
| .option = options, | |
| .version = LIBAVUTIL_VERSION_INT, | |
| .category = AV_CLASS_CATEGORY_DEMUXER, | |
| }; | |
| const FFInputFormat ff_apng_demuxer = { | |
| .p.name = "apng", | |
| .p.long_name = NULL_IF_CONFIG_SMALL("Animated Portable Network Graphics"), | |
| .p.flags = AVFMT_GENERIC_INDEX, | |
| .p.priv_class = &demuxer_class, | |
| .priv_data_size = sizeof(APNGDemuxContext), | |
| .read_probe = apng_probe, | |
| .read_header = apng_read_header, | |
| .read_packet = apng_read_packet, | |
| }; |