rfc9626v2.txt | rfc9626.txt | |||
---|---|---|---|---|
skipping to change at line 298 ¶ | skipping to change at line 298 ¶ | |||
between layers assume that a layer with a given TID/LID MAY depend on | between layers assume that a layer with a given TID/LID MAY depend on | |||
a layer or layers with the same or lower TID/LID, but they MUST NOT | a layer or layers with the same or lower TID/LID, but they MUST NOT | |||
depend on a layer or layers with higher TID/LID. | depend on a layer or layers with higher TID/LID. | |||
With further information, for example, possible future RTCP source | With further information, for example, possible future RTCP source | |||
description (SDES) items that convey full layer structure | description (SDES) items that convey full layer structure | |||
information, it may be possible to map these TIDs and LIDs to | information, it may be possible to map these TIDs and LIDs to | |||
specific absolute frame rates, resolutions, bitrates, and explicit | specific absolute frame rates, resolutions, bitrates, and explicit | |||
dependencies between layers. Such additional layer information may | dependencies between layers. Such additional layer information may | |||
be useful for forwarding decisions in the RTP switch but is beyond | be useful for forwarding decisions in the RTP switch but is beyond | |||
the scope of this memo. The relative layer information is still | the scope of this document. The relative layer information is still | |||
useful for many selective forwarding decisions, even without such | useful for many selective forwarding decisions, even without such | |||
additional layer information. | additional layer information. | |||
3.2. Short Extension for Non-Scalable Streams | 3.2. Short Extension for Non-Scalable Streams | |||
The following RTP header extension is RECOMMENDED for non-scalable | The following RTP header extension is RECOMMENDED for non-scalable | |||
streams. It is identical to the shortest form of the extension for | streams. It is identical to the shortest form of the extension for | |||
scalable streams, except the last four bits (B and TID) are replaced | scalable streams, except the last four bits (B and TID) are replaced | |||
with zeros. It MAY also be used for scalable streams if the sender | with zeros. It MAY also be used for scalable streams if the sender | |||
has limited or no information about stream scalability. The ID is | has limited or no information about stream scalability. The ID is | |||
skipping to change at line 420 ¶ | skipping to change at line 420 ¶ | |||
The D bit MUST be 1 if either: | The D bit MUST be 1 if either: | |||
* the payload's NAL unit header's NRI field is 0, or | * the payload's NAL unit header's NRI field is 0, or | |||
* the payload is an aggregation packet or fragmentation unit | * the payload is an aggregation packet or fragmentation unit | |||
encapsulating only NAL units with NRI = 0. | encapsulating only NAL units with NRI = 0. | |||
Otherwise, it MUST be 0. | Otherwise, it MUST be 0. | |||
These ranges cover non-reference frames as well as filler data. | The NRI = 0 condition signals non-reference frames. | |||
The B bit cannot be determined reliably from simple inspection of | The B bit cannot be determined reliably from simple inspection of | |||
payload headers; therefore, it is determined by implementation- | payload headers; therefore, it is determined by implementation- | |||
specific means. For example, internal codec interfaces may provide | specific means. For example, internal codec interfaces may provide | |||
information to set this reliably. | information to set this reliably. | |||
The TID and layer ID MUST match the correspondingly named fields in | The TID and layer ID MUST match the correspondingly named fields in | |||
the H265 NAL unit header, with layer ID aligned in the least | the H265 NAL unit header, with layer ID aligned in the least | |||
significant 6 bits of the 8-bit LID field and zeros in the most | significant 6 bits of the 8-bit LID field and zeros in the most | |||
significant 2 bits. | significant 2 bits. | |||
3.3.3. H264 Scalable Video Coding (SVC) LID Mapping | 3.3.3. H264 Scalable Video Coding (SVC) LID Mapping | |||
The following shows H264-SVC [RFC6190] Layer encoding information (3 | The following shows H264-SVC [RFC6190] Layer encoding information (3 | |||
bits for spatial/dependency layer, 4 bits for quality layer, and 3 | bits for spatial/dependency layer (DID), 4 bits for quality layer | |||
bits for temporal layer) mapped to the generic LID and TID fields. | (QID), and 3 bits for temporal layer) mapped to the generic LID and | |||
TID fields. | ||||
The S, E, I, and D bits MUST match the correspondingly named bits in | The S, E, I, and D bits MUST match the correspondingly named bits in | |||
Payload Content Scalability Information (PACSI) payload structures. | Payload Content Scalability Information (PACSI) payload structures. | |||
The I bit MUST be 1 when the NAL unit type is 5, 7, 8, 13, 15, or an | The I bit MUST be 1 when the NAL unit type is 5, 7, 8, 13, 15, or an | |||
aggregation packet or fragmentation unit encapsulating any of these | aggregation packet or fragmentation unit encapsulating any of these | |||
types; otherwise, it MUST be 0. These ranges cover intra (IDR) | types; otherwise, it MUST be 0. These ranges cover intra (IDR) | |||
frames as well as critical parameter sets (SPS/PPS variants). | frames as well as critical parameter sets (SPS/PPS variants). | |||
The D bit MUST be 1 if either: | The D bit MUST be 1 if either: | |||
skipping to change at line 645 ¶ | skipping to change at line 646 ¶ | |||
into consideration to balance the privacy leakage risk against the | into consideration to balance the privacy leakage risk against the | |||
potential benefit of optimized media delivery when deciding whether | potential benefit of optimized media delivery when deciding whether | |||
to negotiate and encrypt this header extension. | to negotiate and encrypt this header extension. | |||
5. IANA Considerations | 5. IANA Considerations | |||
This document defines a new extension URI listed in the "RTP Compact | This document defines a new extension URI listed in the "RTP Compact | |||
Header Extensions" subregistry of the "Real-Time Transport Protocol | Header Extensions" subregistry of the "Real-Time Transport Protocol | |||
(RTP) Parameters" registry, according to the following data: | (RTP) Parameters" registry, according to the following data: | |||
Extension URI: urn:ietf:params:rtp-hdrext:framemarkinginfo | Extension URI: urn:ietf:params:rtp-hdrext:framemarking | |||
Description: Frame marking information for video streams | Description: Frame marking information for video streams | |||
Contact: mzanaty@cisco.com | Contact: mzanaty@cisco.com | |||
Reference: RFC 9626 | Reference: RFC 9626 | |||
6. References | 6. References | |||
6.1. Normative References | 6.1. Normative References | |||
End of changes. 4 change blocks. | ||||
5 lines changed or deleted | 6 lines changed or added | |||
This html diff was produced by rfcdiff 1.48. |