Hi Glen, you're right, there is still some redundant information in time domain between frames. This is on purpose, as Codec2 is meant to be a real-time speech codec for wireless transmissions, which generelly speaking has to be considered to have bad channels... The main idea is that you can lose one frame (e.g. 40 ms) and can still decode the next frame without prior knowledge. That is one major advantage compared to closed speech codecs: with codec2 we have full control over all layers from physical (modulation) to coding (error correction/detection INCLUDING source encoding!). That enables tuning between all layers for best overall performance, which is in the end legibility (not necessarily a minimum BER).
I agree that if you want to encode speech on a PC in non-realtime, you may apply an additional compression on top. That is if you want to save some Kbytes unless your speech file is of multi-hour duration... :-D Regards, Stefan Am 29. Dezember 2023 00:44:35 MEZ schrieb glen english LIST <glenl...@cortexrf.com.au>: >Hi Tomas >"codec2 + zip makes for even smaller files" > >implying that there is still redundancy to remove in the codec2 encoded voice >files ???? >That sounds like low hanging fruit to pick. > >I guess though that is across a large number of frames (an audio book), where >there may be redundancy / repeats of common codewords. IE----not just a >single frame. speech pauses , and for the same speaker, phonemes and other >speech components. > >Interesting ! > >On 28/12/2023 9:09 pm, Tomas Härdin wrote: >> codec2 + zip makes for even smaller files > > >_______________________________________________ >Freetel-codec2 mailing list >Freetel-codec2@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/freetel-codec2
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