Even when you upload a video with lossless ( FLAC) audio, YouTube transcodes it into AAC and then plays it back at 48kbps, 128kpps, and 256kbps respectively, depending on the selected audio quality settings, but never at 320kbps bitrate. Unfortunately, there is technically no way to upload audio to YouTube without quality loss. The platform automatically encodes all audio tracks from uploaded videos into the formats that YouTube supports. YouTube Audio Encoding and Its Impact on Quality
