document how the RTP marker bit is passed for video frames,

and why this does not overwrite useful information.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@77248 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/rtp.c b/main/rtp.c
index 1bdb1b92cdb74ebc1be63ccdc81cc0e57a078d39..f481f1e919cc5166003bc86b6c6dd89da523e9e6 100644 (file)
--- a/main/rtp.c
+++ b/main/rtp.c
@@ -1598,6 +1598,11 @@ struct ast_frame *ast_rtp_read(struct ast_rtp *rtp)
                rtp->lastividtimestamp = timestamp;
                rtp->f.delivery.tv_sec = 0;
                rtp->f.delivery.tv_usec = 0;
+               /* Pass the RTP marker bit as bit 0 in the subclass field.
+                * This is ok because subclass is actually a bitmask, and
+                * the low bits represent audio formats, that are not
+                * involved here since we deal with video.
+                */
                if (mark)
                        rtp->f.subclass |= 0x1;
        } else {