QuickTime Streaming

Packet Table Format

Each entry in the packet table specifies one RTP packet. All packets specified in the table have the same RTP timestamp, which is the hint sample time. Multiple entries indicate that a media sample has been split into multiple packets.

Each packet table entry includes a data table. Each entry in the data table indicates a block of data to include in the packet. A packet table entry can include multiple data table entries.

A packet table entry can include an Extra Information TLV table that can be used to extend the RTP hint sample format on a per-packet basis.

The size of a packet table entry is 12 bytes, plus 16 bytes for each data table entry, plus the size of the Extra Information TLV table, if present. The format of packet table entries is shown below.

Table 4 Packet table entry format

Field	Bytes	Description
Relative transmission time	4	32-bit signed integer containing a transmission time offset in hint track timescale units. Add this number to the RTP transmission time, which is also the hint sample time. Negative numbers are used to send data early for data smoothing. Positive numbers are used for repeating data.
RTP header info	2	A 16-bit field specifying various RTP header values. Bits are defined as follows: 0-1 -- reserved 2 -- corresponds to the 'P' packing bit in the RTP header 3 -- corresponds to the 'X' extension bit in the RTP header 4-7 -- reserved 8 -- corresponds to the 'M' marker bit in the RTP header 9-15 -- The seven-bit payload type corresponding to the 'PT' payload type field in the RTP header. Note : Bits 2 and 3 should probably not be set.
RTP sequence number	2	16-bit integer specifying the RTP sequence number for this packet. The server adds a random offset to this number. Packets with different transmission times and the same sequence number can be used to periodically re-transmit data.
Flags	2	16-bit field specifying various attributes of this packet. Bits are defined as follows: 0-12 -- reserved 13 -- X, if set, this table entry contains Extra Information TLVs 14 -- B, if set, this is a B-frame packet. Skip if necessary. 15 -- R, if set, this is a repeated packet. Skip if necessary. If your server is running out of real time, it can skip B-frame packets and/or repeated packets until it catches up.
Entry count	2	A 16-bit integer specifying the number of entries in the data table
Extra Information TLVs	variable	If the X bit in the flags field is set, an Extra Information TLV table goes here. The Extra Information TLV table is defined below.
Data table	variable	Each entry in the data table includes or points to a block of data that your server must include in the packet. The data table format is defined below.