[FFmpeg-devel] Microsoft Smooth Streaming

Michael Niedermayer michaelni at gmx.at
Wed Oct 26 16:17:25 CEST 2011


pOn Wed, Oct 26, 2011 at 10:50:46AM +0200, Nicolas George wrote:
> Le quartidi 4 brumaire, an CCXX, Marcus Nascimento a écrit :
[...]
> > I'm not sure how a decoder works, but I believe there is a way to configure
> > that in order to receive future "injected" data.
> > 
> > If you get all the way here, I really thank you!
> > I wonder how to fit all this into the ffmpeg structure.
> 
> I will elaborate slightly on top of what Michael wrote.
> 
> The "standard" scheme for ffmpeg has three completely separate layers:
> 
> 	protocol -> demuxer -> codecs
> 
> The protocol takes a string (an URL of some kind) and outputs a stream of
> bytes. The most basic protocol is the file protocol, which takes a file name
> and just reads that file. Protocols can be nested (for example mmsh
> internally uses http which internally uses TCP), but that is an
> implementation detail that is not seen in the API (yet; there are plans to
> do something for complex multistreams protocols).
> 
> The demuxer reads a stream of bytes and then first populates a global data
> structure, including one or several streams. Then it outputs a series of
> packets. Packets are a sequence of bytes attached to a few simple
> informations: size, timestamp, stream of attachment.
> 
> The codecs decode the packets. There is normally one codec per stream,
> except if that stream is ignored. The codec initialize itself with the data
> in the stream data structure, then accepts packets and possibly outputs
> video frames, audio PCM data or anything else (subtitles).
> 
> AFAIK, in ffmpeg, the separation between demuxers and codecs has no real
> exception. Which means that you should be able to ignore completely the
> problem of codecs.
> 
> On the other hand protocols and demuxer sometimes need to work hand in hand.

I think this should be put into docs/ or the trac wiki. Its a very good
highlevel overview of the demuxer/decoder side.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Incandescent light bulbs waste a lot of energy as heat so the EU forbids them.
Their replacement, compact fluorescent lamps, much more expensive, dont fit in
many old lamps, flicker, contain toxic mercury, produce a fraction of the light
that is claimed and in a unnatural spectrum rendering colors different than
in natural light. Ah and we now need to turn the heaters up more in winter to
compensate the lower wasted heat. Who wins? Not the environment, thats for sure
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