speex audio transcoding to ac3

Hi , How to add a transcoding for converting speex audio to ac3.

Following is the media information:
Stream #0:0: Video: h264 (High), yuv420p, 640x360, 400 kb/s, 25 tbr, 1k tbn, 50 tbc
Stream #0:1: Audio: speex, 16000 Hz, mono, s16, 27 kb/s

I have a samsung-d series tv.

Thanks, meensu.

[zip]

speex is not supported yet