well, yes, you are mostly right. In case both songs are in mp3 format and you are parsing mp3 file yourself and your code is talking directly to mp3 decoding dsp task you could do some shortcuts like this. The other half of the problem is that nobody talks directly to dsp like this (except mplayer, ask Serge how dead easy it was). DSP is wrapped in gstreamer framework so for each file gstreamer pipeline with several elements is constructed and then started. This takes some time on the beginning of each file. I'm not sure you can pre-create such pipeline for next song while first one is playing and somehow queue/join them so there is no gap. And also I'm not sure you can feed next song to existing pipeline since the pipeline is specific to that file and its properties (song name and other tags, position, length, codec, bitrate, ...).

Well many things are possible but I wouldn't call it dead easy or child's play. Maybe for mp3 songs one could make shoutcast stream out of them and feed local network connection to gstreamer :-) Not sure what to do when you have mixed playlist with mp3, ogg and aac songs then.

BTW, I admit I don't understand both gstreamer and dsp tasks enough to be on your 'dead easy' level so I may be wrong with lot of stuff described above.