The information on client behaviour is purely informative and does not imply any normative procedures on DASH client implementations. The Annex primarily refers to Annex A of ISO/IEC 23009-1 [43].

See ISO/IEC 23009-1 [43], clause A.2.

See ISO/IEC 23009-1 [43], clause A.3.

See ISO/IEC 23009-1 [43], clause A.4.

See ISO/IEC 23009-1 [43], clause A.5.

See ISO/IEC 23009-1 [43], clause A.6.

See ISO/IEC 23009-1 [43], clause A.7.

See ISO/IEC 23009-1 [43], clause A.8.

If the DASH client issued a regular HTTP GET request including an accept header with application/3gpp-partial, i.e. a partial-file-accept request. it may receive one of the following responses.

• 200 OK with the Content-Type set to application/3gpp-partial and the message format according to the definition in clause 7.9.2.2 of TS 26.346.
• 416 Requested Range Not Satisfiable with the additional information according to the definition in clause 7.9.2.2 of TS 26.346.

If the 416 code is received, the 3GP-DASH client should conceal the lost media that is contained in this lost segment and should continue its regular operation, by downloading the next Segment in the Representation that contains a random access point, i.e. a SAP type 1 or 2. If the 200 OK code (or other 2xx success status codes) with the Content-Type set to application/3gpp-partial is received, the 3GP-DASH client should continue its regular operation, by downloading the next Segment in the Representation that contains a random access point, i.e. a SAP type 1 or 2. In addition, the 3GP-DASH client may use the information in the body of the response in order to advantageously conceal the lost media as follows:

• If the content range starting from the first byte is included in the response,
  • the 3GP-DASH client may decode and present all complete access units that are included in the initial byte range.
  • the 3GP-DASH client may parse the Segment Index and/or movie fragment header in order to identify SAPs or sync samples that may be used to decode and render additional information.
• If the content range starting from the first position is not included in the response and the extension header 3gpp-access-position is not present, the 3GP DASH client may discard all information and treat the media segment as lost.
• If the content range starting from the first position is not included in the response and the extension header 3gpp-access-position is present and has a value that is part of the content range,
  • then the 3GP-DASH client may access and decode from the indicated position using regular box parsing mechanisms in order to identify SAPs or sync samples that may be used to decode and render additional information contained in this range or in other ranges.

A DASH client may take into consideration available QoS information when requesting representations such that the consumed content bandwidth remains within the limits established by the signalled QoS information, see clause 6.8.3 of TR 26.938.

Quality metadata refers to video quality metrics based on associated measurements of the media data, as described in clause 16 of TS 26.244. A DASH client may take into consideration Quality Metadata when requesting representations, see clause 6.17 of TR 26.938.