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Reversing Novatek NT966xx firmware.

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  • #91
    Few head scratching questions,
    1) where would a Bit Rate data value limit be located? A129 DVR loads but recording doesn't start.
    2) where are the Default values for settings stored, such as Frequency 50/60 & GPS info stamp for alterations?


    • BCHobbyist
      BCHobbyist commented
      Editing a comment
      Was going to spend more time looking at this next item but will tip my hand now.
      Noticed many different data retrieval commands checking card reader for very specific key words (video being made shortly). Of the approx 6 key words one looks very much like an import of Data values or calling a Function from the memory card.
      Without actually typing the key words here, a general question : could Novatek SDK receive Image Quality changes directly from either a Function call off card and/or keyword folders that contain the actual new IQ data tables for import without recompiling changes the normal way?

    • Dex
      Dex commented
      Editing a comment
      I suppose that I find it properly but not on your FW:

      ROM:801B029C SysResetFlag: # CODE XREF: Save_MenuInfo:loc_801B1044p
      ROM:801B029C # SysReset_MenuInfo+Cp ...
      ROM:801B029C var_4 = -4
      ROM:801B029C addiu $sp, -8
      ROM:801B02A0 li $v0, 0x8062BB40
      ROM:801B02A8 sw $fp, 8+var_4($sp)
      ROM:801B02AC move $fp, $sp
      ROM:801B02B0 li $v1, 1 # one of default values
      ROM:801B02B4 li $a0, 2 # one of default values
      ROM:801B02B8 li $a3, 0xD # one of default values
      ROM:801B02BC li $a2, 6 # one of default values
      ROM:801B02C0 move $sp, $fp
      ROM:801B02C4 li $t0, 3 # one of default values
      ROM:801B02C8 li $a1, 0x64 # one of default values
      ROM:801B02CC sw $a3, 0x108($v0) # Store Word
      ROM:801B02D0 sw $a0, 0xEC($v0) # Store Word
      ROM:801B02D4 sw $a0, 0xF4($v0) # Store Word
      ROM:801B02D8 sw $a0, 0xE8($v0) # Store Word
      ROM:801B02DC sw $a3, 0x10C($v0) # Store Word
      ... many more sw

      About realtime changes for IQ: i think about too and my point of view that it`s theoretical (!) possible only if use Novatek console (via UART) commands like write_to_mem (I don`t sure that it exist, it was many time ago then I played with Novatek console) and known address for IQ valuable tables (in RAM I suppose, not in ROM so it`s additional trouble). If I need change something without reflash FW I go to this way.

    • BCHobbyist
      BCHobbyist commented
      Editing a comment
      Thanks nutsey and Dex for your ideas suggestions and experience with my MODS.

  • #92
    1) Receiving numerous requests to add 1 second delay during startup Logo display. Guessing its one of the default settings and not adjustable via hex. any tricks known?


    • Dex
      Dex commented
      Editing a comment
      I successful find and modify splash screen delay for my GIT1. Look into System_OnBoot() func. Or I may find it in your FW for you but it`s not for free.

  • #93
    Tobi@s repacking that single BCL partition from 96683 fw with BCF v3.3 results in a couple of changes (repacked on the right):
    Click image for larger version

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    • #94
      If someone made mods with switch from MOV to MP4 file format make a note to use MEDIAREC_RECPARAM_ENDTYPE properly:
      // MP4 cannot support seamless recording
      if ((UI_GetData(FL_MOVIE_CYCLIC_REC) != MOVIE_CYCLIC_REC_OFF) && (uiFileType != MEDIAREC_MP4))
      Some firmwares does not have this code and use MEDIAREC_ENDTYPE_CUTOVERLAP directly. So you need patch it to MEDIAREC_ENDTYPE_NORMAL.
      Or you got ERROR in Novatek console: "ERR:MR_MovUpdateHeader() ^R CutOverlap audio CANNOT be AAC !!!!!" which cause mute at last second of video file.

      Also I read at SDK that "MP4 doesn't support power off protection".
      And MP4 format use AAC(lossy) vs PCM(lossless) for MOV files.

      So, that advantages we got for MP4 files vs MOV files (except a bit less file size due audio stream compression) ?


      • Dex
        Dex commented
        Editing a comment
        hc1982 Hi. Git1 use worse schematic for internal microphone than Git2, it was described at forum. So you never make same audio quality as for Git2.
        Git2 audio is better, I think it is related to the NTK96660 chipset, also we plan to use a better MIC on Git2
        We started the Git2 at very early time, but not the first one to release the camera based on NTK96660. To improve the audio quality, even we re-designed the PCB, as this new internal MIC assembled differently.
        Git1 ...*if record with external MIC while charging, there will be some noise. The reason is that the charging and MIC circuit is so close, so the audio will be affected while charging from some port. This part is similar to Hero 3+, and is not easy to solve the noise problem.
        It was fixed for Git2 and later. Git1 was first cam for new GitUp brand but anyway it`s really good cam.

        For myself I did not make decision MOV/MP4, need test how many bytes saves AAC codec. But I did not use FFMPEG or another video editor software, just use Git1 as dash cam.

      • hc1982
        hc1982 commented
        Editing a comment
        I believe, space saving should be around ~4MB per minute.
        As for me, Git2 feels superior in every aspect, except sensor noise in low light.
        BTW, are you using Git1 as dash cam with stock lens? I use Git1 for casual family video recordings indoor in dim light conditions, and looks like finally found relatively fast lens (3mm, f2.1) with low distortion and it was one of the top improvements for video quality, although it is not related to firmware modding.

      • Dex
        Dex commented
        Editing a comment
        4 MB/min is not too much for me so I move back to MOV format. Yes, Git1 with stock lens, now use with FW from StreetGuardian SG9665GC + my patches. It`s allow me use external GPS module and rec files with speed/lat/lon info. But it`s just for me because display/WiFi/g-sensor does not working (I wasted enough time to fix display but something loose from my vision, WiFi never been working (no such module in FW) , g-sensor can be fixed i believe).
        Now I try use G3 Duo as dash cam but it have some disadvantages and I loose feedback from manufacturer about future FW improvements so ... I not very satisfied about G3 Duo as dash cam now. I prefer use Git1 as dash cam but need second cam + GPS... may be sometimes I start make patches for G3 too but not now. Git2 - I`m agree with you opinion.