Guide for HTC HD2 full two-way in-call recording

I am not going to argue with you regarding the reasons you may want to record your incoming or outgoing calls, nor how it is illegal or only partially legal in some countries.
There are a couple of issues with full duplex phonecall recording on the untouched HD2:

  1. the other person’s voice is very faint and totally unhearable when speaking in loud environments
  2. the recording stops after a minute or so, and longer phonecalls are cut after that delay

The reasons for this are

  1. the sound for the third party is not recorded directly, but only what comes from the speaker through to the mic is hearable
  2. the device enters a sleep mode after a certain delay when in a phonecall, so anything which is not radio related is shut down

The main concern until a while ago was the first problem, the second being addressed by a pre-existing  registry hack by I don’t really know who (I’d be happy to credit them, but XDA member shinoby_uk only released a CAB of those pre-esisting hacks, so he is not the real author); this neverending issue (which in time led some people to think that it was a hardware limitation, while I’ve always believed in the hidden software switch) has been solved (according to the XDA member who published the solution) by member RekGRpth; the existing registry hacks that were released by XDA member mskip (if I am not wrong) and worked for previous HTC models, are still needed, even if are not sufficient by themselves to enable full recording.

So here is the complete list of registry keys to add/modify in order to enable full 2way incall recording on the HD2:

[HKLM > Drivers > BuiltIn > WaveDev]

[HKLM > Drivers > BuiltIn > RIL]

[HKCU > ControlPanel > Phone]

[HKCU > ControlPanel > BackLight]

[HKLM > System > AudioRecording]

[HKLM > Software > Microsoft > Voice]

Once you have done so, you are still not done, as you will need a program to actually record the calls; the one I use is the simple but deadly efficient ACR by XDA member slothie.

  This article has been Digiproved

10 thoughts on “Guide for HTC HD2 full two-way in-call recording”

  1. Hello ephestione, thank you very much for this guide. It works on my HD2 with original ROM. Had to first install the ACR though, since he was the one creating [HKLM > System > AudioRecording].

    Still, it does not work as good as i hoped, since the voice of the peoples on the other end is clearly dimmed, so i don’t always hear everything they say on the recording file.

    I left the initial settings of the ACR unchanged, i moved to your guide step by step, the only thing i did a little different being that i had changed “LightSensorPollingEnable”=integer:0 to dword:0, since i couldn’t find any integer option. Anyway, don’t think that this has anything to do with the recording part.

    My question for you is: do you know how could i increase the volume of the 2nd party voice on my recording?

    Thank you for this guide!

    1. Ah I see… well the final test would be to temporarily delete the “mixmoderecord” key, and see what kind of quality you get, if it’s even worse then it means you are already getting full quality with ACR.
      And by the way, as far as I know ACR is both the most efficient program around for that purpose, and has the best quality you can get, as any recording program just saves to file the audio that is routed through the system, so changing software doesn’t actually change sound quality, unless you’re applying a very bad compression to the audio itself.

  2. Hi, that reg key is just for nosleep purposes and doesn’t interfere in any way with the audio quality.
    For the second party to be hearable you absolutely need to add all the reg keys in this guide, the first one, with “MixModeRecord” is the last one that enabled the true 2-way recording, but all the others are necessary anyway.
    This is exact science, as anyone on XDA who had all those registry edits in place could succesfully record the other party.

  3. I too am able to record the other party, i followed your guide step by step, adding every registry key in it. The only problem i have is that i do not hear the other party very good. After testing with about 5 persons, i realized that with four of them the quality was poor, but with a fifth the quality was actually very very good. Can’t really explain why, it is not carrier related. Don’t know about the makes and models they’re using, it might be that, i don’t know. Maybe i’m the only one having this particular problem, that might also be true.

    Anyway, your guide does work, and that’s the important thing. I will try other programs too, maybe i won’t be having this problem with them.

  4. Thank you for your advice ephestione, i will keep that in mind. But for know it seems that the quality got better without doing anything. How come, i don’t know. But if i’ll be having any more problems i’ll remember the mixmoderecord trick :-). Or maybe it will help someone else.

    Thank you again for this guide and for your time with me :-).

  5. No need to test what’s already working then, happy to know the stuff in here is useful to someone 😛
    Probably you just needed to soft reset in order for the tweaks to kick in

  6. Ciao Ephestione, un grazie per la guida! Ho difficoltà a porre in essere le modifiche perchè non capisco che tipo di chiave devo creare per quanto riguarda:
    [HKCU > ControlPanel > BackLight]
    “LightSensorPollingEnable”=integer:0 .
    E’ una chiave, una stringa, un valore binario (non dovrebbe essere un DWORD, altrimenti la sintassi sarebbe stata uguale agli altri…

  7. Ciao Rocco
    grazie della domanda utile 🙂 In realtà non so dove ho trovato quell'”integer”, nel mio registro quel valore è di typo DWORD, ho appena corretto la guida.

  8. Grazie te, io mi sono buttato e (dopo qualche ricerca su google) sono arrivato a dedurre che fosse un DWORD con un numero intero piuttosto che in altre forme…funziona!!!!

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