diff options
Diffstat (limited to 'libavformat/apngdec.c')
-rw-r--r-- | libavformat/apngdec.c | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c new file mode 100644 index 0000000..6deff3b --- /dev/null +++ b/libavformat/apngdec.c @@ -0,0 +1,447 @@ +/* + * 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; + + int64_t pkt_pts; + 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(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(AVCodecContext *s, AVIOContext *pb, int len) +{ + int previous_size = s->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(s->extradata, new_size + FF_INPUT_BUFFER_PADDING_SIZE); + if (!new_extradata) + return AVERROR(ENOMEM); + s->extradata = new_extradata; + s->extradata_size = new_size; + + if ((ret = avio_read(pb, s->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->codec->codec_type = AVMEDIA_TYPE_VIDEO; + st->codec->codec_id = AV_CODEC_ID_APNG; + st->codec->width = avio_rb32(pb); + st->codec->height = avio_rb32(pb); + if ((ret = av_image_check_size(st->codec->width, st->codec->height, 0, s)) < 0) + return ret; + + /* extradata will contain every chunk up to the first fcTL (excluded) */ + st->codec->extradata = av_malloc(len + 12 + FF_INPUT_BUFFER_PADDING_SIZE); + if (!st->codec->extradata) + return AVERROR(ENOMEM); + st->codec->extradata_size = len + 12; + AV_WB32(st->codec->extradata, len); + AV_WL32(st->codec->extradata+4, tag); + AV_WB32(st->codec->extradata+8, st->codec->width); + AV_WB32(st->codec->extradata+12, st->codec->height); + if ((ret = avio_read(pb, st->codec->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->codec, pb, len + 12)) < 0) + goto fail; + acTL_found = 1; + ctx->num_frames = AV_RB32(st->codec->extradata + ret + 8); + ctx->num_play = AV_RB32(st->codec->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->codec, pb, len + 12)) < 0) + goto fail; + } + } + +fail: + if (st->codec->extradata_size) { + av_freep(&st->codec->extradata); + st->codec->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 || 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]->codec->width || + height != s->streams[0]->codec->height || + x_offset != 0 || + y_offset != 0) { + if (sequence_number == 0 || + x_offset >= s->streams[0]->codec->width || + width > s->streams[0]->codec->width - x_offset || + y_offset >= s->streams[0]->codec->height || + height > s->streams[0]->codec->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); + 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 = ctx->pkt_pts; + pkt->duration = ctx->pkt_duration; + ctx->pkt_pts += 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]->codec->extradata_size + 8, SEEK_SET)) < 0) + return ret; + return 0; + default: + { + char tag_buf[32]; + + av_get_codec_tag_string(tag_buf, sizeof(tag_buf), tag); + avpriv_request_sample(s, "In-stream tag=%s (0x%08X) len=%"PRIu32, tag_buf, 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_INT, { .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 = DEFAULT_APNG_FPS }, 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, +}; |