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

[Benjamin Otte]

So, I've spent a while thinking about the problem and the proposed solution.

First of all, I think the solution is not very good, for 2 reasons: a
lack of understanding of multimedia from the person writing it up and
the second is that such a huge list doesn't make it easy for the
application developer to decide which format to use. Should someone
that wants to use some format really have to check audio codec, video
codec and container format? Where does it put Ogg Skeleton support for
the subtitles?

But most of all, I think extending the supported video formats of
Flash is not very useful. I can see two reasons for this. The first is
promoting the Flash format, which still is the last thing I want. The
second is to allow videos with features that aren't available today.
And the only feature that Flash video formats don't give you yet is
Freedom. But if you care about Freedom, you don't use Flash, you use
HTML5 and <video> with Ogg Theora. So the proper solution for the Free
video problem is Firefox 3.1 and a little Javascript.
Or am I missing something?

Cheers,
Benjamin


On Mon, Sep 22, 2008 at 10:42 AM, strk <address@hidden> wrote:
> 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.
>
>