Doesn't work with planar sample formats

[Former user]

Libav 9 introduced planar sample formats and converted audio codecs to use these instead of interleaving the samples in the codec after decoding. Unfortunately av_audio_convert doesn't deal with planar formats, so libavresample should be used.

[Lukáš Lalinský]

This was fixed in 1.0, but only for FFmpeg, not libav. 1.1 (released yesterday) added support for libav as well.