Hi All, I've been experimenting with Codec2 for voice reconstruction. I've found something odd.
I have a ~2 second long wav file, 8 Khz, 16 bit pcm, mono. I can encode this file into codec2 no problem. The first 1.3 seconds is silence. The mic is on, but in a quiet room with no noise. The wav file spectogram shows a flat line, near 0, with just a little white noise, for these 1.3 seconds, followed by a quiet envelope of speech sounds. So, I encode the wav file into codec2, decode it and playback. Sounds fine. Then, I start deleting frames at the head of the encoding. So, I delete frame 0, then frame 1 .. frame 15. That's about 300 ms of sound I've removed that has no human sounds in it -- just mic whitenoise. Then, something weird happens. While there's still a lot of silence in the playback, when playback reaches the speech, the voice is noticeably degraded. I can delete 10 frames, no problem. When I delete more than 10, degradation starts, and increases as I delete more frames. Anyone have any hints on why? Thanks, Imran -- Imran [email protected] ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
