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HEADER SECTION:
1. Real Media File Format tag: .RMF [Real Media File] (File header)
2. Header Blocks:-
PROP Properties block
CONT Content description block [for Title / Author / Copyright]
MDPR Media Properties Block (incl. MIME type)
[NB: The order of these three Blocks is arbitrary]
3. DATA SECTION:
DATA Data block [Audio data]
INDX Index Block [located at the END of the file]
-----------------------------------------------------------------------
Headers in a Real Media file:
1. File
2. Properties
3. Media
4. Content
5. Data Chunk
6. Data Packet
7. Index Section
8. Index Record
EDITING can be done using any hex editor
http://www.cheatmonster.pwp.blueyonder.co.uk/Downloads/Hexeditor.zip
-----------------------------------------------------------------------
HEADER SECTION
File Header Block (First 18 bytes):
Bytes Name Description
----- ------ -----------
4 Object ID ID of block [MUST be .RMF]
4 Size Size of File Header block
(NB: Always 18 bytes [12h])
2 Object version The version of the File Header object
(NB: This is always zero)
4 File version The PN version of the file
(NB: This can be either zero or 1)
4 Num headers The number of headers [blocks] which
follow, and which make up the file
(NB: Always 5 [PROP, MDPR, CONT,
DATA, INDX])
Properties Block [PROP]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be PROP]
4 Size Size of Properties block (in hex)
(NB: Always 50 bytes [32h])
2 Object version Version number (NB: Always zero)
4 Max bit rate Maximum data transmission rate (in hex)
(NB: AC44 = 44,100 [bps])
4 Avg bit rate Average data transmission rate
4 Max packet size Maximum packet size (640 bytes [280 hex])
4 Avg packet size Average packet size (640 bytes [280 hex])
4 Num packets Number of data packets [in the DATA block]
4 Duration Duration of the audio stream, in milliseconds
(NB: Divide by 60,000 to convert to
Minutes)
4 Preroll Duration of buffering before starting
playback, in milliseconds (usually zero)
4 Index offset Offset to start of the index block, in bytes
(NB: Identifies start of INDX block)
4 Data offset Offset of the data block (in hex)
(NB: Identifies start of DATA block)
2 Num streams Number of streams (1=Audio only,
2=Audio+Video)
2 Flags Sets the characteristics of the file:
0001 = save enabled [Allows save]
0002 = perfect-play enabled
[Extra buffering]
0004 = live broadcast
Media Properties block [MDPR]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be MDPR]
4 Size Size of MDPR block (in hex)
2 Object version Version number (NB: Always zero)
2 Stream Number Stream ID number
(NB: Audio stream is always Stream 0)
4 Max bit rate Maximum data transmission rate (in hex)
(NB: AC44 = 44,100 [bps] )
4 Avg bit rate Average data transmission rate
4 Max pack size Largest packet size (640 [280h])
(NB: Must agree with Max packet size
in PROP)
4 Avg pack size Average packet size (640 [280h])
(NB: Must agree with Avg packet size
in PROP)
4 Starting time Starting time of audio stream
(NB: Always starts at zero minutes)
4 Preroll Duration of buffering, in milliseconds
(NB: Must agree with Preroll in PROP)
4 Duration Duration of the audio stream, in milliseconds
(NB: Must agree with Duration in PROP)
1 Stream name size - Length of stream name, in bytes [2D hex]
n Stream name Name of stream (length as above)
(NB: 45 bytes [2D hex] =
audio/x-pn-multirate-realaudio logical stream)
1 MIME type size Length of MIME type, in bytes [14 hex]
n MIME type MIME type of stream (length as above)
(NB: 20 bytes [14 hex] = audio/x-pn-realaudio)
4 Type-dep. size Length of type-dependent Data, in bytes
[NB: 5E hex = 94 bytes]
n Type-dep. data Type-dependent data
[NB: Includes .ra, .ra5, genrcook]
Content Description block [CONT]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be CONT]
4 Size Size of CONT block (in hex)
2 Object version Version number (NB: Always zero)
2 Title size Length of Title description, in bytes
n Title Title description
2 Author size Length of Author description, in bytes
n Author Author description
2 Copyright size Length of Copyright description, in bytes
n Copyright Copyright description
2 Comment size Length of Comment, in bytes
(NB: Always zero)
n Comment Comment (NB: Actually, no bytes are alloted
to this, as comment length is zero)
-----------------------------------------------------------------------
DATA SECTION
Data block [DATA]:
Bytes Name Description
----- ------ -----------
4 Object ID ID of block [MUST be DATA]
4 Size Size of DATA block (in hex)
(NB: Must it agree with size in PROP?)
2 Object version Version number (NB: Always zero)
4 Num packets Number of data packets in file
4 Next data header Offset of next DATA header
(NB: Always zero - there is only
one DATA chunk in a file)
Data Packet header:
Bytes Name Description
----- ------ -----------
2 Object ID ID of block
2 Length Length of packet, in bytes
2 Stream number Stream ID number
(NB: Audio stream is always Stream 0)
4 Timestamp Timestamp of packet, in milliseconds
1 Reserved Reserved
1 Flag Sets the characteristics of the file:
0001 = Reliable flag
0002 = Keyframe flag
n Data Media data
-----------------------------------------------------------------------
Index Section
Index Header:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be INDX]
4 Size Size of INDX block, in bytes (hex)
2 Object version Version number (NB: Always zero)
4 Num indices Number of Indices in the INDX block
2 Stream number Stream ID number
(NB: Audio stream is always Stream 0)
4 Next index header - Offset of next Index header
Index Record:
Bytes Name Description
----- ------ -----------
2 Object version Version number (NB: Always zero)
4 Timestamp Timestamp of packet, in milliseconds
4 Offset Offset of Data packets
4 Packet count Packet number
[All headers are required except the Index Header]
1. Real Media File Format tag: .RMF [Real Media File] (File header)
2. Header Blocks:-
PROP Properties block
CONT Content description block [for Title / Author / Copyright]
MDPR Media Properties Block (incl. MIME type)
[NB: The order of these three Blocks is arbitrary]
3. DATA SECTION:
DATA Data block [Audio data]
INDX Index Block [located at the END of the file]
-----------------------------------------------------------------------
Headers in a Real Media file:
1. File
2. Properties
3. Media
4. Content
5. Data Chunk
6. Data Packet
7. Index Section
8. Index Record
EDITING can be done using any hex editor
http://www.cheatmonster.pwp.blueyonder.co.uk/Downloads/Hexeditor.zip
-----------------------------------------------------------------------
HEADER SECTION
File Header Block (First 18 bytes):
Bytes Name Description
----- ------ -----------
4 Object ID ID of block [MUST be .RMF]
4 Size Size of File Header block
(NB: Always 18 bytes [12h])
2 Object version The version of the File Header object
(NB: This is always zero)
4 File version The PN version of the file
(NB: This can be either zero or 1)
4 Num headers The number of headers [blocks] which
follow, and which make up the file
(NB: Always 5 [PROP, MDPR, CONT,
DATA, INDX])
Properties Block [PROP]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be PROP]
4 Size Size of Properties block (in hex)
(NB: Always 50 bytes [32h])
2 Object version Version number (NB: Always zero)
4 Max bit rate Maximum data transmission rate (in hex)
(NB: AC44 = 44,100 [bps])
4 Avg bit rate Average data transmission rate
4 Max packet size Maximum packet size (640 bytes [280 hex])
4 Avg packet size Average packet size (640 bytes [280 hex])
4 Num packets Number of data packets [in the DATA block]
4 Duration Duration of the audio stream, in milliseconds
(NB: Divide by 60,000 to convert to
Minutes)
4 Preroll Duration of buffering before starting
playback, in milliseconds (usually zero)
4 Index offset Offset to start of the index block, in bytes
(NB: Identifies start of INDX block)
4 Data offset Offset of the data block (in hex)
(NB: Identifies start of DATA block)
2 Num streams Number of streams (1=Audio only,
2=Audio+Video)
2 Flags Sets the characteristics of the file:
0001 = save enabled [Allows save]
0002 = perfect-play enabled
[Extra buffering]
0004 = live broadcast
Media Properties block [MDPR]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be MDPR]
4 Size Size of MDPR block (in hex)
2 Object version Version number (NB: Always zero)
2 Stream Number Stream ID number
(NB: Audio stream is always Stream 0)
4 Max bit rate Maximum data transmission rate (in hex)
(NB: AC44 = 44,100 [bps] )
4 Avg bit rate Average data transmission rate
4 Max pack size Largest packet size (640 [280h])
(NB: Must agree with Max packet size
in PROP)
4 Avg pack size Average packet size (640 [280h])
(NB: Must agree with Avg packet size
in PROP)
4 Starting time Starting time of audio stream
(NB: Always starts at zero minutes)
4 Preroll Duration of buffering, in milliseconds
(NB: Must agree with Preroll in PROP)
4 Duration Duration of the audio stream, in milliseconds
(NB: Must agree with Duration in PROP)
1 Stream name size - Length of stream name, in bytes [2D hex]
n Stream name Name of stream (length as above)
(NB: 45 bytes [2D hex] =
audio/x-pn-multirate-realaudio logical stream)
1 MIME type size Length of MIME type, in bytes [14 hex]
n MIME type MIME type of stream (length as above)
(NB: 20 bytes [14 hex] = audio/x-pn-realaudio)
4 Type-dep. size Length of type-dependent Data, in bytes
[NB: 5E hex = 94 bytes]
n Type-dep. data Type-dependent data
[NB: Includes .ra, .ra5, genrcook]
Content Description block [CONT]:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be CONT]
4 Size Size of CONT block (in hex)
2 Object version Version number (NB: Always zero)
2 Title size Length of Title description, in bytes
n Title Title description
2 Author size Length of Author description, in bytes
n Author Author description
2 Copyright size Length of Copyright description, in bytes
n Copyright Copyright description
2 Comment size Length of Comment, in bytes
(NB: Always zero)
n Comment Comment (NB: Actually, no bytes are alloted
to this, as comment length is zero)
-----------------------------------------------------------------------
DATA SECTION
Data block [DATA]:
Bytes Name Description
----- ------ -----------
4 Object ID ID of block [MUST be DATA]
4 Size Size of DATA block (in hex)
(NB: Must it agree with size in PROP?)
2 Object version Version number (NB: Always zero)
4 Num packets Number of data packets in file
4 Next data header Offset of next DATA header
(NB: Always zero - there is only
one DATA chunk in a file)
Data Packet header:
Bytes Name Description
----- ------ -----------
2 Object ID ID of block
2 Length Length of packet, in bytes
2 Stream number Stream ID number
(NB: Audio stream is always Stream 0)
4 Timestamp Timestamp of packet, in milliseconds
1 Reserved Reserved
1 Flag Sets the characteristics of the file:
0001 = Reliable flag
0002 = Keyframe flag
n Data Media data
-----------------------------------------------------------------------
Index Section
Index Header:
Bytes Name Description
----- ------ ------------
4 Object ID ID of block [MUST be INDX]
4 Size Size of INDX block, in bytes (hex)
2 Object version Version number (NB: Always zero)
4 Num indices Number of Indices in the INDX block
2 Stream number Stream ID number
(NB: Audio stream is always Stream 0)
4 Next index header - Offset of next Index header
Index Record:
Bytes Name Description
----- ------ -----------
2 Object version Version number (NB: Always zero)
4 Timestamp Timestamp of packet, in milliseconds
4 Offset Offset of Data packets
4 Packet count Packet number
[All headers are required except the Index Header]