3 * Copyright (c) 2014 Benoit Fouet
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @see https://wiki.mozilla.org/APNG_Specification
26 * @see http://www.w3.org/TR/PNG
30 #include "avio_internal.h"
32 #include "libavutil/imgutils.h"
33 #include "libavutil/intreadwrite.h"
34 #include "libavutil/opt.h"
35 #include "libavcodec/apng.h"
36 #include "libavcodec/png.h"
37 #include "libavcodec/bytestream.h"
39 #define DEFAULT_APNG_FPS 15
41 typedef struct APNGDemuxContext {
54 int extra_data_updated;
66 * To be a valid APNG file, we mandate, in this order:
74 static int apng_probe(AVProbeData *p)
80 bytestream2_init(&gb, p->buf, p->buf_size);
82 if (bytestream2_get_be64(&gb) != PNGSIG)
86 len = bytestream2_get_be32(&gb);
90 tag = bytestream2_get_le32(&gb);
91 /* we don't check IDAT size, as this is the last tag
92 * we check, and it may be larger than the probe buffer */
93 if (tag != MKTAG('I', 'D', 'A', 'T') &&
94 len + 4 > bytestream2_get_bytes_left(&gb))
98 case MKTAG('I', 'H', 'D', 'R'):
101 if (av_image_check_size(bytestream2_get_be32(&gb), bytestream2_get_be32(&gb), 0, NULL))
103 bytestream2_skip(&gb, 9);
106 case MKTAG('a', 'c', 'T', 'L'):
109 bytestream2_get_be32(&gb) == 0) /* 0 is not a valid value for number of frames */
111 bytestream2_skip(&gb, 8);
114 case MKTAG('I', 'D', 'A', 'T'):
119 /* skip other tags */
120 bytestream2_skip(&gb, len + 4);
126 return AVPROBE_SCORE_MAX;
129 static int append_extradata(APNGDemuxContext *ctx, AVIOContext *pb, int len)
131 int previous_size = ctx->extra_data_size;
133 uint8_t *new_extradata;
135 if (previous_size > INT_MAX - len)
136 return AVERROR_INVALIDDATA;
138 new_size = previous_size + len;
139 new_extradata = av_realloc(ctx->extra_data, new_size + AV_INPUT_BUFFER_PADDING_SIZE);
141 return AVERROR(ENOMEM);
142 ctx->extra_data = new_extradata;
143 ctx->extra_data_size = new_size;
145 if ((ret = avio_read(pb, ctx->extra_data + previous_size, len)) < 0)
148 return previous_size;
151 static int send_extradata(APNGDemuxContext *ctx, AVPacket *pkt)
153 if (!ctx->extra_data_updated) {
154 uint8_t *side_data = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, ctx->extra_data_size);
156 return AVERROR(ENOMEM);
157 memcpy(side_data, ctx->extra_data, ctx->extra_data_size);
158 ctx->extra_data_updated = 1;
163 static int apng_read_header(AVFormatContext *s)
165 APNGDemuxContext *ctx = s->priv_data;
166 AVIOContext *pb = s->pb;
170 int64_t ret = AVERROR_INVALIDDATA;
173 if (avio_rb64(pb) != PNGSIG)
176 /* parse IHDR (must be first chunk) */
179 if (len != 13 || tag != MKTAG('I', 'H', 'D', 'R'))
182 st = avformat_new_stream(s, NULL);
184 return AVERROR(ENOMEM);
186 /* set the timebase to something large enough (1/100,000 of second)
187 * to hopefully cope with all sane frame durations */
188 avpriv_set_pts_info(st, 64, 1, 100000);
189 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
190 st->codecpar->codec_id = AV_CODEC_ID_APNG;
191 st->codecpar->width = avio_rb32(pb);
192 st->codecpar->height = avio_rb32(pb);
193 if ((ret = av_image_check_size(st->codecpar->width, st->codecpar->height, 0, s)) < 0)
196 /* extradata will contain every chunk up to the first fcTL (excluded) */
197 ctx->extra_data = av_malloc(len + 12 + AV_INPUT_BUFFER_PADDING_SIZE);
198 if (!ctx->extra_data)
199 return AVERROR(ENOMEM);
200 ctx->extra_data_size = len + 12;
201 AV_WB32(ctx->extra_data, len);
202 AV_WL32(ctx->extra_data+4, tag);
203 AV_WB32(ctx->extra_data+8, st->codecpar->width);
204 AV_WB32(ctx->extra_data+12, st->codecpar->height);
205 if ((ret = avio_read(pb, ctx->extra_data+16, 9)) < 0)
208 while (!avio_feof(pb)) {
209 if (acTL_found && ctx->num_play != 1) {
210 int64_t size = avio_size(pb);
211 int64_t offset = avio_tell(pb);
215 } else if (offset < 0) {
218 } else if ((ret = ffio_ensure_seekback(pb, size - offset)) < 0) {
219 av_log(s, AV_LOG_WARNING, "Could not ensure seekback, will not loop\n");
223 if ((ctx->num_play == 1 || !acTL_found) &&
224 ((ret = ffio_ensure_seekback(pb, 4 /* len */ + 4 /* tag */)) < 0))
228 if (len > 0x7fffffff) {
229 ret = AVERROR_INVALIDDATA;
235 case MKTAG('a', 'c', 'T', 'L'):
236 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
237 (ret = append_extradata(ctx, pb, len + 12)) < 0)
240 ctx->num_frames = AV_RB32(ctx->extra_data + ret + 8);
241 ctx->num_play = AV_RB32(ctx->extra_data + ret + 12);
242 av_log(s, AV_LOG_DEBUG, "num_frames: %"PRIu32", num_play: %"PRIu32"\n",
243 ctx->num_frames, ctx->num_play);
245 case MKTAG('f', 'c', 'T', 'L'):
247 ret = AVERROR_INVALIDDATA;
250 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0)
254 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
255 (ret = append_extradata(ctx, pb, len + 12)) < 0)
261 if (ctx->extra_data_size) {
262 av_freep(&ctx->extra_data);
263 ctx->extra_data_size = 0;
268 static int decode_fctl_chunk(AVFormatContext *s, APNGDemuxContext *ctx, AVPacket *pkt)
270 uint32_t sequence_number, width, height, x_offset, y_offset;
271 uint16_t delay_num, delay_den;
272 uint8_t dispose_op, blend_op;
274 sequence_number = avio_rb32(s->pb);
275 width = avio_rb32(s->pb);
276 height = avio_rb32(s->pb);
277 x_offset = avio_rb32(s->pb);
278 y_offset = avio_rb32(s->pb);
279 delay_num = avio_rb16(s->pb);
280 delay_den = avio_rb16(s->pb);
281 dispose_op = avio_r8(s->pb);
282 blend_op = avio_r8(s->pb);
283 avio_skip(s->pb, 4); /* crc */
285 /* default is hundredths of seconds */
288 if (!delay_num || delay_den / delay_num > ctx->max_fps) {
290 delay_den = ctx->default_fps;
292 ctx->pkt_duration = av_rescale_q(delay_num,
293 (AVRational){ 1, delay_den },
294 s->streams[0]->time_base);
296 av_log(s, AV_LOG_DEBUG, "%s: "
297 "sequence_number: %"PRId32", "
299 "height: %"PRIu32", "
300 "x_offset: %"PRIu32", "
301 "y_offset: %"PRIu32", "
302 "delay_num: %"PRIu16", "
303 "delay_den: %"PRIu16", "
317 if (width != s->streams[0]->codecpar->width ||
318 height != s->streams[0]->codecpar->height ||
321 if (sequence_number == 0 ||
322 x_offset >= s->streams[0]->codecpar->width ||
323 width > s->streams[0]->codecpar->width - x_offset ||
324 y_offset >= s->streams[0]->codecpar->height ||
325 height > s->streams[0]->codecpar->height - y_offset)
326 return AVERROR_INVALIDDATA;
327 ctx->is_key_frame = 0;
329 if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS)
330 dispose_op = APNG_DISPOSE_OP_BACKGROUND;
331 ctx->is_key_frame = dispose_op == APNG_DISPOSE_OP_BACKGROUND ||
332 blend_op == APNG_BLEND_OP_SOURCE;
338 static int apng_read_packet(AVFormatContext *s, AVPacket *pkt)
340 APNGDemuxContext *ctx = s->priv_data;
343 AVIOContext *pb = s->pb;
347 * fcTL chunk length, in bytes:
354 * 4 (tag (must be fdAT or IDAT))
356 /* if num_play is not 1, then the seekback is already guaranteed */
357 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 46)) < 0)
363 case MKTAG('f', 'c', 'T', 'L'):
365 return AVERROR_INVALIDDATA;
367 if ((ret = decode_fctl_chunk(s, ctx, pkt)) < 0)
370 /* fcTL must precede fdAT or IDAT */
373 if (len > 0x7fffffff ||
374 tag != MKTAG('f', 'd', 'A', 'T') &&
375 tag != MKTAG('I', 'D', 'A', 'T'))
376 return AVERROR_INVALIDDATA;
378 size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */;
380 return AVERROR(EINVAL);
382 if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0 ||
383 (ret = av_append_packet(pb, pkt, size)) < 0)
386 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
392 tag != MKTAG('f', 'c', 'T', 'L') &&
393 tag != MKTAG('I', 'E', 'N', 'D')) {
394 if (len > 0x7fffffff)
395 return AVERROR_INVALIDDATA;
396 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
397 (ret = av_append_packet(pb, pkt, len + 12)) < 0)
399 if (ctx->num_play == 1 && (ret = ffio_ensure_seekback(pb, 8)) < 0)
404 if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0)
407 if (ctx->is_key_frame)
408 pkt->flags |= AV_PKT_FLAG_KEY;
409 pkt->pts = ctx->pkt_pts;
410 pkt->duration = ctx->pkt_duration;
411 ctx->pkt_pts += ctx->pkt_duration;
412 return send_extradata(ctx, pkt);
413 case MKTAG('I', 'E', 'N', 'D'):
415 if (ctx->ignore_loop || ctx->num_play >= 1 && ctx->cur_loop == ctx->num_play) {
416 avio_seek(pb, -8, SEEK_CUR);
419 if ((ret = avio_seek(pb, ctx->extra_data_size + 8, SEEK_SET)) < 0)
421 return send_extradata(ctx, pkt);
426 av_get_codec_tag_string(tag_buf, sizeof(tag_buf), tag);
427 avpriv_request_sample(s, "In-stream tag=%s (0x%08X) len=%"PRIu32, tag_buf, tag, len);
428 avio_skip(pb, len + 4);
432 /* Handle the unsupported yet cases */
433 return AVERROR_PATCHWELCOME;
436 static int apng_read_close(AVFormatContext *s)
438 APNGDemuxContext *ctx = s->priv_data;
439 av_freep(&ctx->extra_data);
440 ctx->extra_data_size = 0;
444 static const AVOption options[] = {
445 { "ignore_loop", "ignore loop setting" , offsetof(APNGDemuxContext, ignore_loop),
446 AV_OPT_TYPE_BOOL, { .i64 = 1 } , 0, 1 , AV_OPT_FLAG_DECODING_PARAM },
447 { "max_fps" , "maximum framerate (0 is no limit)" , offsetof(APNGDemuxContext, max_fps),
448 AV_OPT_TYPE_INT, { .i64 = DEFAULT_APNG_FPS }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
449 { "default_fps", "default framerate (0 is as fast as possible)", offsetof(APNGDemuxContext, default_fps),
450 AV_OPT_TYPE_INT, { .i64 = DEFAULT_APNG_FPS }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
454 static const AVClass demuxer_class = {
455 .class_name = "APNG demuxer",
456 .item_name = av_default_item_name,
458 .version = LIBAVUTIL_VERSION_INT,
459 .category = AV_CLASS_CATEGORY_DEMUXER,
462 AVInputFormat ff_apng_demuxer = {
464 .long_name = NULL_IF_CONFIG_SMALL("Animated Portable Network Graphics"),
465 .priv_data_size = sizeof(APNGDemuxContext),
466 .read_probe = apng_probe,
467 .read_header = apng_read_header,
468 .read_packet = apng_read_packet,
469 .read_close = apng_read_close,
470 .flags = AVFMT_GENERIC_INDEX,
471 .priv_class = &demuxer_class,