set_if_changed(changed, stream.sampleformat, static_cast<AVSampleFormat>(av_frame.format));
set_if_changed(changed, stream.num_channels, av_frame.channels);
set_if_changed(changed, stream.sampleformat, static_cast<AVSampleFormat>(av_frame.format));
set_if_changed(changed, stream.num_channels, av_frame.channels);