avformat: add MODS demuxer

Changelog

@@ -19,6 +19,7 @@ version <next>:
 - MobiClip FastAudio decoder
 - MobiClip video decoder
 - MOFLEX demuxer
+- MODS demuxer
 
 
 version 4.3:

libavformat/Makefile

@@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o riffdec.o
 OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
 OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
 OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
+OBJS-$(CONFIG_MODS_DEMUXER)              += mods.o
 OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
 OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o replaygain.o
 OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o vpcc.o \

libavformat/allformats.c

@@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
 extern AVInputFormat  ff_mm_demuxer;
 extern AVInputFormat  ff_mmf_demuxer;
 extern AVOutputFormat ff_mmf_muxer;
+extern AVInputFormat  ff_mods_demuxer;
 extern AVInputFormat  ff_moflex_demuxer;
 extern AVInputFormat  ff_mov_demuxer;
 extern AVOutputFormat ff_mov_muxer;

libavformat/mods.c

@@ -0,0 +1,100 @@
+/*
+ * MODS demuxer
+ * Copyright (c) 2020 Paul B Mahol
+ *
+ * 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
+ */
+
+#include "libavutil/intreadwrite.h"
+
+#include "avformat.h"
+#include "internal.h"
+
+static int mods_probe(const AVProbeData *p)
+{
+    if (memcmp(p->buf, "MODSN3\x0a\x00", 8))
+        return 0;
+    if (AV_RB32(p->buf + 8) == 0)
+        return 0;
+    if (AV_RB32(p->buf + 12) == 0)
+        return 0;
+    if (AV_RB32(p->buf + 16) == 0)
+        return 0;
+    return AVPROBE_SCORE_MAX;
+}
+
+static int mods_read_header(AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    AVRational fps;
+    int64_t pos;
+
+    AVStream *st = avformat_new_stream(s, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    avio_skip(pb, 8);
+
+    st->nb_frames            = avio_rl32(pb);
+    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    st->codecpar->codec_id   = AV_CODEC_ID_MOBICLIP;
+    st->codecpar->width      = avio_rl32(pb);
+    st->codecpar->height     = avio_rl32(pb);
+
+    fps.num = avio_rl32(pb);
+    fps.den = 0x1000000;
+    avpriv_set_pts_info(st, 64, fps.den, fps.num);
+
+    avio_skip(pb, 16);
+
+    pos = avio_rl32(pb) + 4;
+    avio_seek(pb, pos, SEEK_SET);
+    pos = avio_rl32(pb);
+    avio_seek(pb, pos, SEEK_SET);
+
+    return 0;
+}
+
+static int mods_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    AVIOContext *pb = s->pb;
+    unsigned size;
+    int64_t pos;
+    int ret;
+
+    if (avio_feof(pb))
+        return AVERROR_EOF;
+
+    pos = avio_tell(pb);
+    size = avio_rl32(pb) >> 14;
+    ret = av_get_packet(pb, pkt, size);
+    pkt->pos = pos;
+    pkt->stream_index = 0;
+    pkt->flags |= AV_PKT_FLAG_KEY;
+
+    return ret;
+}
+
+AVInputFormat ff_mods_demuxer = {
+    .name           = "mods",
+    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MODS"),
+    .read_probe     = mods_probe,
+    .read_header    = mods_read_header,
+    .read_packet    = mods_read_packet,
+    .extensions     = "mods",
+    .flags          = AVFMT_GENERIC_INDEX,
+};

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
-#define LIBAVFORMAT_VERSION_MINOR  52
+#define LIBAVFORMAT_VERSION_MINOR  53
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \