Measurements on the MPEG-2 Transport Stream - Digital Video and Audio Broadcasting Technology - page 186

A continuity_error (Fig. 11.4.) occurs when

• the same TS packet is transmitted twice without a discontinuity
being indicated, or
• if a packet is missing (count incremented by 2) without a
discontinuity being indicated, or
• the sequence of packets is completely wrong.

Note: The way in which an MPEG-2 decoder reacts to a continuity
counter error when the packet sequence is, in fact, correct depends on the
decoder and the decoder chip used in it.

188 byte

4 byte
header

184 byte
payload

Optional
adaptation
field

Header

Transport
error
indicator

Payload
unit start
indicator

Transport
scrambling
control

Adaptation
field
control

Sync
byte

Transport
priority

Continuity
counter

PID

81 1 1 3 2 2 4 i t

Fig. 11.5. Transport_error

11.7 The Transport_Error (Priority 2)

Every MPEG-2 transport stream packet contains a bit called Transport Er-
ror Indicator which follows directly after the sync byte. This bit flags any
errored transport stream packets at the receiving end. During the transmis-
sion, bit errors may occur due to various types of influences. If error pro-
tection (at least Reed Solomon in DVB and ATSC) is no longer able to re-
pair all errors in a packet, this bit is set. This packet can no longer be
utilized by the MPEG-2 decoder and must be discarded.
A transport_error (Fig. 11.5.) occurs when

• the transport error indicator bit in the TS header is set to 1.