Re: [Gnash-dev] 2nd try: How can Internet Archive flash script pick codec to use?

[strk]

Added swfdec developer in Cc.

Ben, we're trying to define a way for an SWF movie to tell which
containers and codecs are supported by a flash player.

John's drafty draft (below) looks fine to me. What do you think ?

--strk;

On Mon, Sep 22, 2008 at 01:19:42AM -0700, John Gilmore wrote:

> Adobe's description of Flash Lite doesn't say, of course, what the
> mime types are returned for popular formats.  Indeed, this interface
> just looks like it documents the container types, not the codecs.
> There's confirming info about this in a tutorial:
> 
>   http://mobiforge.com/designing/story/flash-lite-and-video-streaming
> 
> which shows "video/3GP" as a returned type, and also describes the
> wide variety of codecs usable within that type.  Dumb.  
> 
> I suggest that we add a parallel interface,
> 
>   System.capabilities.videoDecoderTypes
>   System.capabilities.audioDecoderTypes
>   System.capabilities.videoEncoderTypes
>   System.capabilities.audioEncoderTypes
> 
> which would return the necessary info.
> 
> Then a Flash movie would be able to check for both container support
> and for codec support (for both video and audio, potentially) if it
> wanted to select among copies of a movie in various formats.
> 
> We should also draft a spec for such an interface, put it in the
> public Gnash documentation, and feed it to Adobe for consideration in
> future revisions of Flash.  We can implement it regardless of what
> they do, but at least we'll be doing OUR part to avoid needless
> incompatability.
> 
> Very drafty draft (from this, you already know I don't understand
> ActionScript syntax): In a system with Gnash, configured to use ffmpeg
> or gstreamer, in which the configured media library contains these
> decoders.  (Depending on what other codec plugins are available, lots
> more will also be described in these arrays.)
> 
>   System.capabilities.videoMIMETypes ["video/ogg"] will be true.
>   System.capabilities.audioMIMETypes ["audio/ogg"] will be true.
>   System.capabilities.audioDecoderTypes ["vorbis"] will be true.
>   System.capabilities.audioDecoderTypes ["speex"] will be true.
>   System.capabilities.audioDecoderTypes ["flac"] will be true.
>   System.capabilities.videoDecoderTypes ["theora"] will be true.
> 
> The codec names should generally be in lowercase, so people won't have
> to case-match them.  (We may be stuck with random cases in the MIME
> types, like the above "video/3GP", but at least we can do better in
> our own interface.)  Some will be nonintuitive, e.g. MP3 won't be
> called mp3 because it's real name is something else; mp3 is a
> high-speed collision between a container format and a codec.