[squeak-dev] GStreamer

  Hello, Josh and John and list,

  I'm playing with the GStreamer stuff on Fedora.  With the latest
stuff, and some changes (attached), I managed to play a .ogg file that
*only* has video track.  But there are a few questions:

  * I needed to use the subclasses of GstElemFakeSink to play back,
    assuming that GStreamerElementForSqueak... are being obsoleted.
    Is it right?

  * #checkDimension is only sent but not implemented.  I assumed that
     it wants to check whether the dimension of video is sane, and I
     thought that "sane-ness" is just checking both width and height
     are bigger than zero.  Is it right?

  * #openFile: was written under the assumption that .ogg file is
     either "video and audio" or "audio only" but I have a file that
     is "video only".  If I open a video only file with older
     definition, it basically forever paused and wait until it is
     ready and doesn't play it back.  #openFile: should check the type
     of tracks and call a proper #oggHookupToSqueak... method.  But is
     there a simple way to query it when I have the filesrc element?

  Thank you!

-- Yoshiki

People are often on vacation around this time of year, so have
fun... but at your convenient time, please think about Squeak stuff^^;

On Aug 13, 2008, at 8:01 AM, Yoshiki Ohshima wrote:

Joshua was refactoring all that, I'll look later tonight

>
>
>  * #openFile: was written under the assumption that .ogg file is
>     either "video and audio" or "audio only" but I have a file that
>     is "video only".  If I open a video only file with older
>     definition, it basically forever paused and wait until it is
>     ready and doesn't play it back.  #openFile: should check the type
>     of tracks and call a proper #oggHookupToSqueak... method.  But is
>     there a simple way to query it when I have the filesrc element?

Yes there is a problem there, I was looking at "typefind" to see if we  
could decide what type of file it is, but
that might require a plugin change in order to get the CAPS element  
back.  I was also trying to see if you
could resolve pipeline setup as always both setup with audio/video and  
work with that, but haven't gotten
around to testing it, however you are welcome to try. In this case you  
could ask the elments for attribute data to see
if there are frames, or audio?

--
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John M. McIntosh <[hidden email]>
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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John M McIntosh wrote: It turns out that we don't have time to spend on GStreamer, so I'm not
carrying on with the work right now.  I tried to not disturb code that
was already working, so the other GStreamerElementForSqueakEtc classes
should continue to work.  In other words, you should be able to revert
the implementors of #makeFakeSinkElement: to JMM's versions using the
"old" classes.  However, I think that instantiating the GstElemEtc
classes is significantly nicer, especially for ad-hoc creation of
pipelines in a Workspace.  If I had time to spend, I would continue in
this direction.
>>
>>  * #checkDimension is only sent but not implemented.  


You are seeing sends of #checkDimension in #videoFrameHeight/Width/Rate,
right?  Sorry, my fault... I thought that I removed all senders (but
these were in the GStreamer-UI package, which must be why I missed them).

It should be safe to remove those sends of #checkDimension.  In fact, I
went ahead and did this; the changes are checked in.

Let me know if this works, or if other bugs pop up (quite possible,
since I apparently only tested the latest updates with Workspace
snippets and unit tests, not the Morphic UI).

>> I assumed that
>>     it wants to check whether the dimension of video is sane, and I
>>     thought that "sane-ness" is just checking both width and height
>>     are bigger than zero.  Is it right?
#checkDimension used to look like this:

checkDimension
    self width ifNotNil: [^self].
    width := self squeakerVideo getWidth.
    height := self squeakerVideo getHeight.
    fps := (self squeakerVideo getFrameRateNumerator) /
           (self squeakerVideo getFrameRateDenominator).

However, it doesn't make much sense to retrieve the width, height, and
frame-rate each time you want to access one of the three.

Cheers,
Josh

  I'll give it a try.  Thank you!

-- Yoshiki

At Wed, 13 Aug 2008 16:06:27 -0700,
Joshua Gargus wrote:
  Thank you.  I'm also working on so that the movie player morph can
survive during the saving and restarting image, etc.

> checkDimension
>     self width ifNotNil: [^self].
>     width := self squeakerVideo getWidth.
>     height := self squeakerVideo getHeight.
>     fps := (self squeakerVideo getFrameRateNumerator) /
>            (self squeakerVideo getFrameRateDenominator).
>
> However, it doesn't make much sense to retrieve the width, height, and
> frame-rate each time you want to access one of the three.

  Ok.  Thanks.y

-- Yoshiki

For the typefind one I had tried to use

openFile: aFileName
        | player checkForPending decoder capsPointer capsData capsDataString |

        player := self new.
        player filesrc: aFileName.
        player oggHookupToTypeFind.
        decoder := player pipeLine findElementCalled: 'typefind'.
        player play.
        capsPointer := decoder getKeyValuePointer: 'caps'.
        self halt.
        capsData := GStreamerCaps handle: capsPointer.
        capsDataString := capsData getString.
        self halt.
....



oggHookupToTypeFind
        | file  result typeFind |

        file := GStreamerElement elementFactoryMake: 'filesrc' name: 'filesrc'.
        file setKey: 'location' toStringValue: self filesrc.
        typeFind := GStreamerElement elementFactoryMake: 'typefind' name:  
'typefind'.

        "Setup the pipeline"
        pipeLine := GStreamerPipeline name: 'my-pipeline'.
        pipeLine addElement: file.
        pipeLine addElement: typeFind.

        result := GStreamerSystem default linkElementSrc: file toDest:  
typeFind.



to get back the caps

  caps                : detected capabilities in stream
                         flags: readable
                         Caps (NULL)

But that returns

capsDataString -> "'application/ogg'"

for both audio and video files which is not helpful


On Aug 14, 2008, at 11:51 PM, Yoshiki Ohshima wrote:

--
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========================================================================
John M. McIntosh <[hidden email]>
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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========================================================================

At Fri, 15 Aug 2008 00:15:40 +0200,
John M McIntosh wrote:
  Yes, the command line version (gst-typefind) also returns it.  But
the documentation seems a bit more promising so there may have some
chance.

  I'll also look into if we can use the spider element somehow.

-- Yoshiki