avformat/apngdec: add APNG demuxer.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

4 files changed, 413 insertions, 2 deletions

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 38730c5259..c1b5acee93 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -76,6 +76,7 @@ OBJS-$(CONFIG_AMR_MUXER)                 += amr.o
 OBJS-$(CONFIG_ANM_DEMUXER)               += anm.o
 OBJS-$(CONFIG_APC_DEMUXER)               += apc.o
 OBJS-$(CONFIG_APE_DEMUXER)               += ape.o apetag.o img2.o
+OBJS-$(CONFIG_APNG_DEMUXER)              += apngdec.o
 OBJS-$(CONFIG_AQTITLE_DEMUXER)           += aqtitledec.o subtitles.o
 OBJS-$(CONFIG_ASF_DEMUXER)               += asfdec.o asf.o asfcrypt.o \
                                             avlanguage.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 3f60d7d9c7..81aab56c82 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -74,6 +74,7 @@ void av_register_all(void)
     REGISTER_DEMUXER (ANM,              anm);
     REGISTER_DEMUXER (APC,              apc);
     REGISTER_DEMUXER (APE,              ape);
+    REGISTER_DEMUXER (APNG,             apng);
     REGISTER_DEMUXER (AQTITLE,          aqtitle);
     REGISTER_MUXDEMUX(ASF,              asf);
     REGISTER_MUXDEMUX(ASS,              ass);
diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c
new file mode 100644
index 0000000000..54fbd29c61
--- /dev/null
+++ b/libavformat/apngdec.c
@@ -0,0 +1,409 @@
+/*
+ * 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
+ *
+ * Not supported (yet):
+ *     - streams with chunks other than fcTL / fdAT / IEND after the first fcTL
+ *     - streams with multiple fdAT chunks after an fcTL one
+ */
+
+#include "avformat.h"
+#include "avio_internal.h"
+#include "internal.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/opt.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 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 > 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 ret = AVERROR_INVALIDDATA, acTL_found = 0;
+
+    /* 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);
+
+    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;
+    }
+    s->streams[0]->r_frame_rate.num = delay_den;
+    s->streams[0]->r_frame_rate.den = delay_num;
+    pkt->duration = 1;
+
+    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]->codec->width ||
+        height != s->streams[0]->codec->height ||
+        x_offset != 0 ||
+        y_offset != 0) {
+        if (sequence_number == 0)
+            return AVERROR_INVALIDDATA;
+        ctx->is_key_frame = 0;
+    } else {
+        ctx->is_key_frame = 1;
+    }
+
+    return 0;
+}
+
+static int apng_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    APNGDemuxContext *ctx = s->priv_data;
+    int 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))
+     *
+     *  TODO: support multiple fdAT following an fcTL
+     */
+    /* 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;
+
+        if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0)
+            return ret;
+
+        size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */;
+        if (size > INT_MAX)
+            return AVERROR(EINVAL);
+
+        if ((ret = av_get_packet(pb, pkt, size)) < 0)
+            return ret;
+        if (ctx->is_key_frame)
+            pkt->flags |= AV_PKT_FLAG_KEY;
+        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:
+        avpriv_request_sample(s, "In-stream tag=%#08X len=%"PRId64"", tag, avio_tell(pb));
+    }
+
+    /* 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,
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index 8f14d197b0..6dcf632e32 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
-#define LIBAVFORMAT_VERSION_MINOR  14
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MINOR  15
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \