flvdec: Do not default to a video and audio stream

If no streams were indicated in the FLV header, do not automatically
allocate by default a video and an audio stream. Instead, in the case
that the header did not indicate the presence of any data, allocate no
stream until data actually arrives for one type.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/flvdec.c

@@ -559,14 +559,6 @@ static int flv_read_header(AVFormatContext *s)
 
     avio_skip(s->pb, 4);
     flags = avio_r8(s->pb);
-    /* old flvtool cleared this field */
-    /* FIXME: better fix needed */
-    if (!flags) {
-        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
-        av_log(s, AV_LOG_WARNING,
-               "Broken FLV file, which says no streams present, "
-               "this might fail.\n");
-    }
 
     s->ctx_flags |= AVFMTCTX_NOHEADER;