RTP Control Protocol (RTCP) Extended Report (XR) Block for MPEG-2 Transport Stream (TS) Program Specific Information (PSI) Independent Decodability Statistics Metrics Reporting
Extracted elements (21)
Only first-priority (necessary for decodability) and second-priority (recommended for continuous monitoring) ETSI TR 101290 indicators are reported; third-priority indicators are excluded because they are application-dependent and do not apply to all MPEG-2 implementations.
The block is defined as PSI-independent so that the reported metrics do not rely on Program Specific Information carried in MPEG-2 TS, ensuring the block is broadly applicable across MPEG-2 implementations regardless of PSI availability.
When the report of this block spans more than one measurement interval (per RFC 6776), the metric counts (e.g., Sync byte errors, PCR errors) may reflect problems in either the current or a previous measurement interval.
The Block Length field is the constant 11; the block MUST be discarded if the block length is set to a different value.
The Reserved field (8 bits) MUST be set to zero by senders and ignored by receivers, per RFC 6709 Section 4.2.
XR blocks MAY be used without prior SDP signaling, per Section 5 of RFC 3611. When SDP Offer/Answer is used, the unilateral 'rtcp-xr' attribute parameter rules of RFC 3611 Section 5.2 apply.
Continuity_count_error_count is a 32-bit count of Continuity_count_errors — covering incorrect packet order, a packet occurring more than twice, or a lost packet — within the MPEG-2 TS (ETSI Section 5.2.1).
PCR_accuracy_error_count is a 32-bit count of PCR_accuracy_errors, which occur when PCR accuracy of the selected program is outside the range of +/-500 ns (ETSI Section 5.2.2).
PCR_discontinuity_indicator_error_count is a 32-bit count of PCR_discontinuity_indicator_errors, which occur when the interval between consecutive PCR values exceeds 100 ms (ETSI Section 5.2.2).
PCR_error_count is a 32-bit count of PCR_errors. A PCR_error occurs if the primary clock reference (PCR) is not seen for more than 100 ms; the interval between consecutive PCR values should not exceed 40 ms (ETSI Section 5.2.2).
PCR_repetition_error_count is a 32-bit count of PCR_repetition_errors, which occur when the interval between two consecutive PCR values exceeds 40 ms (ETSI Section 5.2.2).
PTS_error_count is a 32-bit count of PTS_errors, which occur when the Presentation Time Stamp (PTS) repetition is more than 700 ms within the MPEG-2 TS (ETSI Section 5.2.2). The PTS is used to help the decoder present the program on time and synchronized.
SDP signaling for this block uses the 'rtcp-xr' attribute extension with the xr-format token 'ts-psi-indep-decodability' (ABNF: xr-format =/ xr-tpid-block; xr-tpid-block = "ts-psi-indep-decodability").
Sync_byte_error_count is a 32-bit count of Sync_byte_errors in the reported interval. A sync byte error occurs when the sync byte is not equal to 0x47 in any TS packet (ETSI Section 5.2.1).
The MPEG-2 TS PSI-Independent Decodability Statistics Metrics Block (Block Type 22) is an RTCP XR block that carries counts of eight PSI-independent error metrics defined in ETSI TR 101290, covering both first-priority (basic decodability) and second-priority (continuous monitoring) indicators. It is measured at the receiving end of an RTP stream carrying MPEG-2 TS.
Transport_error_count is a 32-bit count of Transport_errors, occurring when an erroneous TS packet cannot be corrected within the MPEG-2 TS (ETSI Section 5.2.2).
TS_sync_loss_count is a 32-bit count of TS_sync_loss errors in the reported sequence number interval. A TS_sync_loss error occurs when there are two or more consecutive incorrect sync bytes within the MPEG-2 TS (ETSI Section 5.2.1).
This document assigns block type value 22 in the IANA 'RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry' to the 'MPEG-2 Transport Stream PSI-Independent Decodability Statistics Metrics Block'.
This document registers the new SDP parameter 'ts-psi-indep-decodability' in the IANA 'RTP Control Protocol Extended Reports (RTCP XR) Session Description Protocol (SDP) Parameters Registry'.
Error counter values may have contractual SLA implications; an attacker could manipulate RTP endpoints into reporting false data, or modify reported data in transit, to cause financial harm to network operators. To prevent this, an authentication and integrity protection framework such as SRTP combined with AVPF into SAVPF (RFC 5124) SHOULD be applied to the RTCP XR block.
The block begins with a 1-octet Block Type (BT=22), 1-octet Reserved field, and a 16-bit Block Length fixed at 11. It is followed by a 32-bit SSRC of Source, 16-bit begin_seq, 16-bit end_seq, and nine 32-bit error-count fields: TS_sync_loss_count, Sync_byte_error_count, Continuity_count_error_count, Transport_error_count, PCR_error_count, PCR_repetition_error_count, PCR_discontinuity_indicator_error_count, PCR_accuracy_error_count, and PTS_error_count.