some updates, fixes discovered by me

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@6351 b3059339-0415-0410-9bf9-f77b7e298cf2

1 files changed, 19 insertions, 14 deletions

diff --git a/DOCS/tech/realcodecs/streaming.txt b/DOCS/tech/realcodecs/streaming.txt
index 483f91a19d..3761c04b5a 100644
--- a/DOCS/tech/realcodecs/streaming.txt
+++ b/DOCS/tech/realcodecs/streaming.txt
@@ -10,14 +10,14 @@ received data between the original viewer and the demuxer.
 
 Every packet may contain one or more sub packets, and one block may
 be contained inside one or more adjacent (sub) packets.
-A sub packet starts with a small header (two letters are one byte):
+A sub packet (fragment) starts with a small header (two letters are one byte):
 
 
-aa(bb)[ccccdddd{eeee}ff]
+aa(bb)[cccc{gggg}dddd{eeee}ff]
 
 aa:   indicates the type of header
       the 2MSB indicate the header type (mask C0)
-      C0:      the [] part exists, but not ()
+      C0:      the [] part exists, but not () -> whole packet (not fragmented)
       00, 80:  the data block is encapsulated inside multiple packets.
                bb contains the sequence number, beginning with 1.
                80 indicates the last sub packet containing data for the
@@ -29,19 +29,24 @@ aa:   indicates the type of header
       40:      [] does not exist, the meaning of bb is unknown to me
                data follows to the end of the packet
       mask 3F: unknown
-bb:   unknown
-cccc: mask 3FFF: length of data
+bb:   sub-seq - mask 0x7f: the sequence number of the _fragment_
+                mask 0x80: unknown, seems to alternating between 00 and 80
+cccc: mask 3FFF: _total_ length of the packet
       mask C000: unknown, seems to be always 4000
+      when it's all 0000, it indicates value >=0x4000, you should read {gggg}
+      and use all 16 bits of it. dunno what happens when length>=65536...
 dddd: when it's 0, {} exists (only in this case)
-      mask 3FFF: I thought it would have been the offset inside the
-                 block, is not correct in every case. Just appending the
-                 data works better, ignoring it.
-      mask C000: like cccc, except the first case
-eeee: only exists when dddd exists and is zero. contains the data
-      dddd should contain in the second case. don't know what the developers
-      had in mind.
-ff:   sequence number for the data blocks, beginning with 0
-
+      mask 3FFF: offset of fragment inside the whole packet. it's counted
+                 from the beginning of the packet, except when hdr&0x80,
+		 hten it's relative to the _end_ of the packet, so it's
+		 equal to fragment size!
+      mask C000: like cccc, except the first case (always 4000)
+      when it's all 0000, it indicates value >=0x4000, you should read {eeee}
+      and use all 16 bits of it. dunno what happens when length>=65536...
+ff:   sequence number of the assembled (defragmented) packets, beginning with 0
+
+NOTE: the demuxer should build a table of the subpacket offsets relative to the
+start of whole packet, it's required by the rv20/rv30 video decoders.
 
 
 packet header: