please tell me what difference auddec and sphdec is?

by the names, I would guess one of them is an audio decoder (e.g. mp3, aac,...) and the other is a speech decoder (e.g. g.711); if you can give me more details where you are seeing this I can look at up tomorrow when I am in the office and give you a more precise answer.

hi

recode sound becomes  G711 speech from mic,then  transform mp3 audio,finally  mp3 are stored in the hdd disk?

is it right ?

I believe the demo from the DM355 DVSDK is only using the G711 speech codec for audio, I see no mention of MP3 in the demos.

The mic most likely provides raw, uncompressed data (not g.711 encoded data).

So if you want to save mic-provided data to an MP3 on disk, you _probably_ just need to "MP3 encode" the raw data provided by the mic driver.  Per Bernie's reply, it's unclear whether the DVSDK includes an MP3 encoder.

Chris