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30 lines
1.2 KiB
Text
30 lines
1.2 KiB
Text
Mutability is the property of an object that defines whether or not you
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are allowed to modify it. In the context of GST, that means that if you
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want to mutilate a buffer, say to do an audio effect, you may have to do
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this on a copy of the buffer, if someone else has a reference on it.
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The simplest sequence of events in a decoder pipeline is as follows:
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1) create buffer
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2) allocate and fill data region, attach to buffer
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3) pass to next element
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4) decode the data into new buffer, free original buffer
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5) pass to next element
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6) buffer gets copied to output device (sound, video, whatever)
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Both of these buffers are created from malloc()'d memory, are referenced
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by one and only one element at a time, and are never modified in place.
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They have no special flags, and when ref==0, they're simply free()'d.
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An optimization in the case of the sound card or video double buffering,
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where the output buffer actually comes from the output device. In that
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case the element will be aware of such things.
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A more complex example is where the data is teed after being decoded, sent
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to an effects or visualization object.
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1) create buffer, fill from source
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2) hand to decoder
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3) create new buffer, decode into it, free old buffer
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4) hand to tee
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5) ref++, hand off to
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