From d5247fb1da615a7ccff9fa7271bc8aba23e0de25 Mon Sep 17 00:00:00 2001 From: Derek Buitenhuis Date: Tue, 23 Jun 2020 16:05:18 +0100 Subject: lavf/movenc: Use a dynamic buffer when writing the mfra box When doing streamed output, with e.g. +dash, if the mfra box ended up being larger than the AVIOContext write buffer, the (unchecked) seeking back to update the box size would silently fail and produce an invalid mfra box. This is similar to how other boxes are written in fragmented mode. Signed-off-by: Derek Buitenhuis --- libavformat/movenc.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/libavformat/movenc.c b/libavformat/movenc.c index b8e45760ee..7db2e28840 100644 --- a/libavformat/movenc.c +++ b/libavformat/movenc.c @@ -4798,28 +4798,40 @@ static int mov_write_tfra_tag(AVIOContext *pb, MOVTrack *track) static int mov_write_mfra_tag(AVIOContext *pb, MOVMuxContext *mov) { - int64_t pos = avio_tell(pb); - int i; + AVIOContext *mfra_pb; + int i, ret, sz; + uint8_t *buf; - avio_wb32(pb, 0); /* size placeholder */ - ffio_wfourcc(pb, "mfra"); + ret = avio_open_dyn_buf(&mfra_pb); + if (ret < 0) + return ret; + + avio_wb32(mfra_pb, 0); /* size placeholder */ + ffio_wfourcc(mfra_pb, "mfra"); /* An empty mfra atom is enough to indicate to the publishing point that * the stream has ended. */ if (mov->flags & FF_MOV_FLAG_ISML) - return update_size(pb, pos); + goto done_mfra; for (i = 0; i < mov->nb_streams; i++) { MOVTrack *track = &mov->tracks[i]; if (track->nb_frag_info) - mov_write_tfra_tag(pb, track); + mov_write_tfra_tag(mfra_pb, track); } - avio_wb32(pb, 16); - ffio_wfourcc(pb, "mfro"); - avio_wb32(pb, 0); /* version + flags */ - avio_wb32(pb, avio_tell(pb) + 4 - pos); + avio_wb32(mfra_pb, 16); + ffio_wfourcc(mfra_pb, "mfro"); + avio_wb32(mfra_pb, 0); /* version + flags */ + avio_wb32(mfra_pb, avio_tell(mfra_pb) + 4); - return update_size(pb, pos); +done_mfra: + + sz = update_size(mfra_pb, 0); + ret = avio_get_dyn_buf(mfra_pb, &buf); + avio_write(pb, buf, ret); + ffio_free_dyn_buf(&mfra_pb); + + return sz; } static int mov_write_mdat_tag(AVIOContext *pb, MOVMuxContext *mov) @@ -6987,7 +6999,9 @@ static int mov_write_trailer(AVFormatContext *s) } if (!(mov->flags & FF_MOV_FLAG_SKIP_TRAILER)) { avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_TRAILER); - mov_write_mfra_tag(pb, mov); + res = mov_write_mfra_tag(pb, mov); + if (res < 0) + return res; } } -- cgit v1.2.3