Re: [MMUSIC] [AVTCORE] Question
worley@ariadne.com (Dale R. Worley) Mon, 29 December 2014 00:30 UTC
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To: Julius Friedman <juliusfriedman@gmail.com>
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Cc: avt@ietf.org, mmusic@ietf.org
Subject: Re: [MMUSIC] [AVTCORE] Question
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Julius Friedman <juliusfriedman@gmail.com> writes: > Rfc 2326 explicitly states that seeking can be disabled by not including > the end information in the range header. > > What if I want to have the end but I don't want to allow seeking? > > E.g. my clip is 10 minutes and I have already been playing for 3 and there > are 7 remaining; why can't I convey that and not allow seeking? I'm no expert in RTSP, but reading the RFC, it appears that the server indicates if seeking is allowed by the inclusion of the end-time: D.2.1 Basic Playback Client implementations may use the presence of length information to determine if the clip is seekable, and visibly disable seeking features for clips for which the length information is unavailable. Exactly why the server cannot indicate the total media length without implicitly stating the media is seekable, I don't know. Perhaps it's because any such media is theoretically seekable, since it must already be instantiated as a stored data object. Or perhaps it is because if seeking is not implemented, the user interface is expected to not display the "slider bar", and so there is no way to tell the user how much time remains in the media: Client implementations may use the presence of length information to determine if the clip is seekable, and visibly disable seeking features for clips for which the length information is unavailable. A common use of the presentation length is to implement a "slider bar" which serves as both a progress indicator and a timeline positioning tool. Perhaps referring to the mailing list discussion for this RFC would reveal the answer. In any case, why would we want to prevent seeking on a stored media object? I can see why if the media is an un-stored media stream, but in that case, the software likely doesn't know the total length that the media will have. Dale
- [MMUSIC] Question Julius Friedman
- Re: [MMUSIC] [AVTCORE] Question Julius Friedman
- Re: [MMUSIC] [AVTCORE] Question Dale R. Worley
- Re: [MMUSIC] [AVTCORE] Question Dale R. Worley
- Re: [MMUSIC] [AVTCORE] Question Julius Friedman
- Re: [MMUSIC] [AVTCORE] Question Dale R. Worley
- [MMUSIC] Erratum 4097 on RFC 2435 Dale R. Worley
- Re: [MMUSIC] [AVTCORE] Question Stephan Wenger
- Re: [MMUSIC] [AVTCORE] Question Julius Friedman
- Re: [MMUSIC] [AVTCORE] Question - Erratum 4097 Dale R. Worley
- Re: [MMUSIC] [AVTCORE] Question - Erratum 4097 Julius Friedman
- Re: [MMUSIC] [AVTCORE] Erratum 4097 on RFC 2435 Magnus Westerlund
- Re: [MMUSIC] [AVTCORE] Question - Erratum 4097 Dale R. Worley
- Re: [MMUSIC] [AVTCORE] Question - Erratum 4097 Frederick, Ron