ReplayGain does not work in AIFF file

[simoncn]

I have reproduced the problem with your AIFF file and also with other AIFF files containing replay gain tags.

With most file formats, the tags precede the audio data. With all the AIFF files I have used for these tests, the tags follow the audio data. It is possible that when FFmpeg is transcoding, it needs to read the replay gain tags before it starts to read the audio data.