avcodec/utils: prettify remap_deprecated_codec_id()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
fate/libswresample: add tests with filter_size=1 phase_shift=0

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
swresample/resample: Fix fractional part of index in the filter_size = 1 filters = 1 case

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
swresample/resample: simplify index/consumed calculation for the filter = 1 case

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>