Facts about the new vocoder used by retevis

[aeickho]

on http://blog.retevis.com/firmware-update-rt3-rt8/ is an note about a "new Vocoder".

Let us collect here what changes in the vocoder have been made.

Close this Issue when the "improvement" is documented :laughing:

[d235j]

I just added an S003.012.bin firmware for older GPS radios in 4bc9727c5fc118047d0b55c468441107176b60c3. A vbindiff between this firmware and the S013.012 firmware shows that they are very similar; I'd probably poke at these to see what they changed with the new "vocoder"; perhaps using radiff2 and comparing changed procedures.

[travisgoodspeed]

With the new symbol migration tool, we can see that S013.012 does lack the ambe_encode_thing() and ambe_decode_wav() functions that are easily identified in S003.012. They do use different vocoders!

S03.012 (old vocoder)

/* Unknown AMBE2+ thing. */
ambe_encode_thing    = 0x08053d99; /* 1024 byte match */
/* Decodes an AMBE2+ frame into bits. */
ambe_unpack          = 0x0804b979; /* 38 byte match */
/* Populates the audio buffer */
ambe_decode_wav      = 0x08054251; /* 504 byte match */

S13.012 (new vocoder)

/* Unknown AMBE2+ thing. */
/* ambe_encode_thing has bad match of 4 points at 0x0802baf9*/
/* Decodes an AMBE2+ frame into bits. */
ambe_unpack          = 0x0804be29; /* 38 byte match */
/* Populates the audio buffer */
/* ambe_decode_wav has bad match of 2 points at 0x0800e399*/

You can try the tool yourself with make clean all in symbols/. All matches are made against the 2.032 firmware.

[travisgoodspeed]

Updated my last comment now that the tool is printing the destination addresses. Before it was printing the source addresses, which were quite a bit less useful.

[adityanag]

I have this new radio and am willing to beta test the firmware updates if you like. I have the original firmware so I can recover if I need to.

[adityanag]

Update - I have been able to successfully install the firmware on my radio with the new vocoder. Everything is working fine.

[travisgoodspeed]

@aeickho Shall we close this issue, now that we have compatibility of each vocoder on the other's hardware?

[aeickho]

my related question was ... what is difference between the too vocoder ... the not alpu relevant part

ok i think the question is to "complicated" ... I'll close