Thanks Greg,
Did what you suggested but did not find the CalibratedXDCodec.component in the folder you indicated. There were other .component files but not the one you mentioned. Will keep trying different settings in Compressor.
Yesterday when this occurred we were compressing/down-converting a 1080i file, (DVC pro HD output from fcp) to 720 x 480 Qucktime H264. This also occurred when converting the same 1080 i source file to mpeg 2.
We even got the same results exporting the same file to other frame sizes in H264 outputs. Then we turned off frame controls in Compressor and the problem went away.
yet when we went back to compressing to mpeg 2 in compressor, form the same source file the problem persisted.
Finally tried Adobe encoder to compress the file to Mpeg 2 and that worked fine. But no luck with Compressor.
Thanks for your post