Re: MPEG-2 TS metadata cue guidelines

On 3/25/14, 11:39 AM, "Clift, Graham" <Graham.Clift@am.sony.com> wrote:

>
>>>In that case, I would suggest startTime to be 0 and endTime to be PTS1.
>>>This means, the cue represents the segment before the ad and can have a
>>>pause-on-exit flag set to true.
>
>The problem with startTime=0 is that during a backward seek, where the UA
>deletes cues generated inband because they will be regenerated again
>during forward playback, the UA will not know which cues to delete. If
>the startTime is set to UA current time then the UA will know to delete
>any cue where the startTime is greater than the seek-to time. As to
>consistency, maybe for streams other than MPEG-2 TS  there might be
>consistency issues (and for those we can adjust the mapping of DataCues
>appropriately) but for MPEG-2 TS the demux + decoding time is set by the
>stream encoding so this should give a consistent result across
>implementations. This is in contrast to the network buffering time which
>could be large and variable, but the textTracks won't be seen until they
>are demuxed from the stream in my understanding.


I was under the impression the UAıs were planning to detect and prevent
duplicates, not just delete cues when seeking backwards. For example,
right now WebKit leaves cues alone when you seek, then doesnıt add cues if
theyıre already in the list.

Received on Tuesday, 25 March 2014 18:25:50 UTC