From e71475e82860bb154ac14f9cb07e75b3d9ecd9a6 Mon Sep 17 00:00:00 2001 From: Zhi Li Date: Tue, 3 Jun 2025 23:15:05 -0700 Subject: [PATCH] Address PTS/DTS section by mapping 'are' to 'shall'. --- index.bs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/index.bs b/index.bs index 7e5c588..e80da41 100644 --- a/index.bs +++ b/index.bs @@ -472,7 +472,7 @@ The highest level that may occur in an AV1 video stream, as well as a profile an For AV1 video stream multiplexed into [[!MPEG-2-TS]], the *decoder_model_info* may not be present. If the *decoder_model_info* is present, then the STD model shall match with the decoder model defined in Annex E of [[!AV1]]. -For synchronization and STD management, PTSs and, when appropriate, DTSs are encoded in the header of the PES packet that carries the AV1 video stream data setting the PTS_DTS_flags to '01' or '11'. For PTS and DTS encoding, the constraints and semantics apply as defined in the PES Header and associated constraints on timestamp intervals. +For synchronization and STD management, PTSs and, when appropriate, DTSs shall be encoded in the header of the PES packet that carries the AV1 video stream data setting the PTS_DTS_flags to '01' or '11'. For PTS and DTS encoding, the constraints and semantics apply as defined in the PES Header and associated constraints on timestamp intervals. There are cases in AV1 bitstreams where information about a frame is sent multiple times. For example, first to be decoded, and subsequently to be displayed. In the case of a frame being decoded but not displayed, it is desired to assign a valid DTS but without need for a PTS. However, the MPEG2-TS specification prevents a DTS from being transmitted without a PTS. Hence, a PTS is always assigned for AV1 access units and its value is not relevant for frames being decoded but not displayed.