Re: [Gnash-dev] New Gstreamer based soundbackend commited

[strk]

Good work Tom.
As you know I've some problems with the dependency on latest
release. Do you think it is possible at all to make the code
work against 0.8.9 ? If not, what's been introduced in latter
versions that make this impossible ?

TIA

--strk;

On Mon, Jul 24, 2006 at 04:11:14PM +0200, Tomas Groth wrote:
> Hi all,
> 
> It has finally happened! Gnash can now use gstreamer to decode and play audio
> sounds! (well mostly anyway...)
> It's not enabled by default, it's a giant walking memory leak, only mp3 sounds
> works and it still needs some work!
> 
> So I hear you ask: "Is this what we've all been waiting for? Is Gstreamer the
> solution to all our problems?" The short answer is: "Not yet", and the longer
> one is: Some parts of gstreamer is still in it's early stages, including the
> adder (the things that enables it to play to sounds at the same time), which 
> we
> use a lot! This means that certain things isn't working at the moment... More
> precisely, movies which starts sounds rapidly after each other will make
> gstreamer choke and die (but gnash will not crash).
> 
> But as far as I know that's the only bug in the current gstreamer stable
> release which causes problems, but you will need gstreamer 0.10.8 (i think),
> since there seems to be other and more severe bugs in earlier versions.
> 
> So what needs to be done? Here a list:
>  * Make the configure system select gstreamer by default, and disable 
> SDL_mixer
>  * Figure out a nice way to free the gstreamer elements after use
>  * Improve the soundstream implementation (I will hopefully be able to do this
> within a day or 2)
>  * Make other soundformat work; ADPCM, raw (maybe vorbis too?)
>  * Probably more...
> 
> And now the gstreamer details:
> Gstreamer works with pipelines, bins and elements. Pipelines are the main bin,
> where all other bins or elements are places. Visually the pipeline looks like
> this:
>  ___
> |Bin|_
> |___| \
>  ___   \ _____       ____________
> |Bin|___|Adder|_____|Audio output|
> |___|   |_____|     |____________|
>  ___   /
> |Bin|_/
> |___|
> 
> 
> There is one bin for each sound which is being played. If a sound is played
> more the once at the same time, multiple bins will be made. The bins contains:
> 
> |source|---|capsfilter|---|decoder|---|aconverter|---|aresampler|---|volume|
> 
> In the source element we place parts of the undecodede sounddata, and when
> playing the pipeline will pull the data from the element. Via callbacks it is
> refilled if needed.
> In the capsfilter the data is labeled with the format of the data.
> The decoder (surprise!) decodes the data.
> The audioconverter converts the now raw sounddata into a format accepted by 
> the
> adder, all input to the adder must in the same format.
> The audioresampler resamples the raw sounddata into a sample accepted by the
> adder, all input to the adder must in the same samplerate.
> The volume element makes it possible to control the volume of each sound.
> 
> That's the basics, and i hope it helps :)
> 
> cheers,
> 
> Tomas
> 
> 
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