[gst-devel] Implementing a MPEGTS segmenter, what's the best approach?

[David Zhao]

On Sun, Jan 2, 2011 at 1:54 PM, Andoni Morales <ylatuya at gmail.com> wrote:

> 2010/12/31 David Zhao <david at davidzhao.com>:
> > Thanks David! That's exactly what I was looking for.
> >
> > On Thu, Dec 30, 2010 at 11:23 PM, David Schleef <ds at entropywave.com>
> wrote:
> >>
> >> On Thu, Dec 30, 2010 at 08:35:21PM -0800, David Zhao wrote:
> >> > Hello,
> >> >
> >> > I'm trying to build a GStreamer plugin that would produce segments of
> >> > MPEGTS
> >> > files, each with a fixed duration. This is to create TS segments for
> the
> >> > Apple HTTP live streaming protocol. I'm fairly new to developing for
> >> > GStreamer and have a basic understanding of how it works.
> >> >
> >> > The approach I had in mind is to create a plugin that includes both
> >> > mpegtsmux and filesink. Within that plugin, it could produce
> individual
> >> > ts
> >> > files when certain duration is accumulated.
> >> >
> >> > Is this feasible? Is there another way to do this without having to
> >> > replicate code that's already in mpegtsmux and filesink?
> >>
> >> gst-launch ... ! mpegtsmux ! multifilesink next-file=key-frame \
> >>    location=%05d.ts
>
> That's probably the quickest way to produce segments for testing
> purpose but these fragments wouldn't follow the spec's
> recommendations[1].
>
> " Transport Stream files MUST contain a single MPEG-2 Program.  There
>   SHOULD be a Program Association Table and a Program Map Table at the
>   start of each file.  A file that contains video SHOULD have at least
>   one key frame and enough information to completely initialize a video
>   decoder."
>
> A client can join the stream at any moment (downloading any of the
> available segments), so each segment must be independently decodable,
> which means you need to start each fragment with a PAT table, followed
> with a PMT table and starting with a keyframe.
>

Thanks for the clarification here. Looks like the "correct" way to implement
this is still to create a special purposed mpegts muxer that will write the
PAT/PMT tables at the beginning of each TS segment.

I noticed that the protocol says "SHOULD" instead of "MUST", perhaps the
current implementation of iOS treat those tables as optional?


>
> Andoni
>
> [1]http://tools.ietf.org/html/draft-pantos-http-live-streaming-05#page-4
> >>
> >>
> >>
> >> David
> >>
> >>
> >>
> >>
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> >
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>
>
> --
> Andoni Morales Alastruey
>
> LongoMatch:The Digital Coach
> http://www.longomatch.ylatuya.es
>
>
> ------------------------------------------------------------------------------
> Learn how Oracle Real Application Clusters (RAC) One Node allows customers
> to consolidate database storage, standardize their database environment,
> and,
> should the need arise, upgrade to a full multi-node Oracle RAC database
> without downtime or disruption
> http://p.sf.net/sfu/oracle-sfdevnl
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