Hello Daniel, Voiced and unvoiced frames are indicated by a single bit in each frame, it's packed and unpacked in codec2.c. It's unlikely that bit errors would cause just a flip in the voiced/unvoiced bit - it's a very small part of the total codec information.
Codecs in DAB are waveform codecs, designed to carry speech, music, general audio waveforms etc. I don't think they would use speech-only model based techniques such as voiced/unvoiced decisions that are used for low bit rate voice. - David On Mon, 2013-01-14 at 12:52 +0000, Daniel Ankers wrote: > Hi list, > I'd like to hear the effects of only playing back unvoiced frames from > a decoded stream, but can't figure out how to do this from the code. > Can anyone give me any hints on how to do this? > > > There is a rationale behind this. I listen to DAB radio in my car, > and twice in the last two weeks the stream has become corrupted > somehow. I *think* that voicing information was being dropped but > unvoiced information was being played. The effect was quite scary to > listen to - it sounded like someone evil in a cheap sci-fi was > talking. However the speech was perfectly intelligible. I'd like to > know if the same is true with Codec2. > > > I've got some code hacked together to add a simple CRC8 checksum to > every 48 bits of data. My plan is to use this to send 1200bps Codec2 > data over the FDMDV modem with some error detection/correction, but > this leaves the problem of what to do with uncorrectable errors. The > first thing I'd like to try doing is playing the uncorrected unvoiced > frames and dropping the uncorrected voice frames - my gut feeling is > that this has a chance of still being intelligible even if it's not > very pleasant to listen to. > > > Regards, > Dan MD1CLV > ------------------------------------------------------------------------------ > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current > with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft > MVPs and experts. SALE $99.99 this month only -- learn more at: > http://p.sf.net/sfu/learnmore_122412 > _______________________________________________ Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122412 _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
