| /* |
| * 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 "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 (previous_size > INT_MAX - len) |
| 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); |
| par->extradata = new_extradata; |
| par->extradata_size = new_size; |
| |
| if ((ret = avio_read(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 = AVERROR_INVALIDDATA; |
| |
| /* verify PNGSIG */ |
| if (avio_rb64(pb) != PNGSIG) |
| return ret; |
| |
| /* parse IHDR (must be first chunk) */ |
| len = avio_rb32(pb); |
| tag = avio_rl32(pb); |
| if (len != 13 || tag != MKTAG('I', 'H', 'D', 'R')) |
| return ret; |
| |
| 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) */ |
| st->codecpar->extradata = av_malloc(len + 12 + AV_INPUT_BUFFER_PADDING_SIZE); |
| if (!st->codecpar->extradata) |
| return AVERROR(ENOMEM); |
| st->codecpar->extradata_size = len + 12; |
| 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 = avio_read(pb, st->codecpar->extradata+16, 9)) < 0) |
| goto fail; |
| |
| while (!avio_feof(pb)) { |
| if (acTL_found && ctx->num_play != 1) { |
| int64_t size = avio_size(pb); |
| int64_t offset = avio_tell(pb); |
| if (size < 0) { |
| ret = size; |
| goto fail; |
| } else if (offset < 0) { |
| ret = offset; |
| goto fail; |
| } 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)) |
| goto fail; |
| |
| len = avio_rb32(pb); |
| if (len > 0x7fffffff) { |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| |
| 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) |
| goto fail; |
| 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) { |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0) |
| goto fail; |
| return 0; |
| default: |
| if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 || |
| (ret = append_extradata(st->codecpar, pb, len + 12)) < 0) |
| goto fail; |
| } |
| } |
| |
| fail: |
| if (st->codecpar->extradata_size) { |
| av_freep(&st->codecpar->extradata); |
| st->codecpar->extradata_size = 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", |
| __FUNCTION__, |
| 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 != 26) |
| 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, |
| }; |
| |
| AVInputFormat ff_apng_demuxer = { |
| .name = "apng", |
| .long_name = NULL_IF_CONFIG_SMALL("Animated Portable Network Graphics"), |
| .priv_data_size = sizeof(APNGDemuxContext), |
| .read_probe = apng_probe, |
| .read_header = apng_read_header, |
| .read_packet = apng_read_packet, |
| .flags = AVFMT_GENERIC_INDEX, |
| .priv_class = &demuxer_class, |
| }; |
