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ffmpeg/libavformat/apngdec.c
Andreas Rheinhardt 790f793844 avutil/common: Don't auto-include mem.h 
There are lots of files that don't need it: The number of object
files that actually need it went down from 2011 to 884 here.

Keep it for external users in order to not cause breakages.

Also improve the other headers a bit while just at it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-31 00:08:43 +01:00

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/*
* 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/mem.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,
};
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