[Openchrome-users] XvMC PutSlice

[Thomas Hellström]

Michael Weber wrote:

>   I am looking into a decoding problem with XvMC, does the XvMC
>PutSlice decode the slice immediately or does it delay until the
>SyncSurface?
>
>mike
>
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It's a bit complicated.

The slice is queued up in an internal buffer.
If you are not using AGP DMA, that buffer is flushed at the end of 
PutSlice and the decoding starts.
SyncSurface polls the engine to make sure it is completed.

If you are using AGP DMA, the buffer is not flushed until it's full, or 
a call to FlushSurface(), and then it is flushed to the kernel AGP 
command queue, which might have other tasks to do before tending to the 
Slice data.

To debug, I think you'd best turn off AGP DMA if you have it enabled.

/Thomas