It might be a stupid beginner question, but I'd like to compress data
in a CVPixelBufferRef at a given frame dimension. The frame dimension
of the data in the pixel buffer differs from the desired dimension.
When using the ICMCompressionSession API, I can specify which
dimension the compressed frames do have. But for some reasons, I have
to use the older CompressSequenceBegin() / CompressSequenceFrame()
API. There, I haven't found a way to tell which size to produce. I'm
creating a PixMap structure with the appropriate informations given
from the pixel buffer. This PixMap is then fed to the compressor.
Example: The data in the buffer has dimension 640x480. I'd like to
compress to H.263 with either CIF (352x288) or QCIF (176x144). Except
for the different aspect ration, this works well for CIF, as the data
is automatically transformed to CIF size during compression. But if I
want to produce QCIF size, the data needs to have already QCIF size
when feeding to the compressor, otherwise, a CIF frame will result.
The data in the CVPixelBuffer will be either k32ARGBPixelFormat or
k16BE555PixelFormat.
Any help is greatly appreciated!
Hannes Friederich
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