From 40665d27e38e6a2f65037878202bd1a398c7683e Mon Sep 17 00:00:00 2001 From: "Uwe L. Korn" Date: Sun, 23 Nov 2014 19:36:14 +0100 Subject: flvdec: Document how the duration is retrieved at the end of the file MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Martin Storsjö --- libavformat/flvdec.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'libavformat/flvdec.c') diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c index 2d5e50e257..0167d17c70 100644 --- a/libavformat/flvdec.c +++ b/libavformat/flvdec.c @@ -845,9 +845,13 @@ skip: if (s->pb->seekable && (!s->duration || s->duration == AV_NOPTS_VALUE)) { int size; const int64_t pos = avio_tell(s->pb); + // Read the last 4 bytes of the file, this should be the size of the + // previous FLV tag. Use the timestamp of its payload as duration. const int64_t fsize = avio_size(s->pb); avio_seek(s->pb, fsize - 4, SEEK_SET); size = avio_rb32(s->pb); + // Seek to the start of the last FLV tag at position (fsize - 4 - size) + // but skip the byte indicating the type. avio_seek(s->pb, fsize - 3 - size, SEEK_SET); if (size == avio_rb24(s->pb) + 11) { uint32_t ts = avio_rb24(s->pb); -- cgit v1.2.3