File sizes on an empty disc: -rwxr-xr-x 1 root root 172 Jul 23 11:07 himd-empty/hmdhifi/00010012.hma -rwxr-xr-x 1 root root 172 Jul 23 11:07 himd-empty/hmdhifi/_0010012.hma -rwxr-xr-x 1 root root 32768 Jul 23 11:07 himd-empty/hmdhifi/_clist01.hma -rwxr-xr-x 1 root root 32768 Jul 23 11:07 himd-empty/hmdhifi/_mdhifi.hma -rwxr-xr-x 1 root root 327680 Jul 23 11:07 himd-empty/hmdhifi/_rkidx01.hma -rwxr-xr-x 1 root root 0 Jul 23 11:07 himd-empty/hmdhifi/atdata01.hma -rwxr-xr-x 1 root root 32768 Jul 23 11:07 himd-empty/hmdhifi/mclist01.hma -rwxr-xr-x 1 root root 327680 Jul 23 11:07 himd-empty/hmdhifi/trkidx01.hma 6x tracks: -rwxr-xr-x 1 root root 172 Jul 2 00:08 00010012.hma -rwxr-xr-x 1 root root 172 Jul 2 00:08 _0010012.hma -rwxr-xr-x 1 root root 32768 Jul 2 00:08 _mdhifi.hma -rwxr-xr-x 1 root root 327680 Jul 23 2006 _rkidx05.hma -rwxr-xr-x 1 root root 360841216 Jul 23 15:37 atdata05.hma -rwxr-xr-x 1 root root 32768 Jul 22 15:17 mclist04.hma -rwxr-xr-x 1 root root 32768 Jul 22 15:22 mclist05.hma -rwxr-xr-x 1 root root 65536 Jul 2 20:52 text_g01.hma -rwxr-xr-x 1 root root 327680 Jul 23 2006 trkidx05.hm Hexediting the Track meta data as well as abbritary positions in the audio data does work (so they are not checksummed). That is the player shows the updated meta data and still plays the audio. The audio data is zero padded to 64k boundaries, that is a new track added starts at: 002C FFF0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 002D 0000: 53 4D 50 41 00 27 00 03 3F 87 00 00 00 00 00 00 SMPA.'.. ?....... Other data beside SMPA: PCM and ATX (seen on Atrac3+ encoded data on MZ-RH1). SMPA appears to be 3des (tripple des) encrypted using one of the schemes: plain, des ecb with session key, des cbc with session key Media Type name: audio Media subtype name: ATRACFAMILY profile: ATRAC, ATRAC3, ATRAC-X frameSampleSize: 512, 1024, 2048 sampleRate: 32000, 44100, 48000, 88100, 96000 frameLength: [license required] channels: 1, 2, 3, 4, 5, 6, 7, 8 File extensions: at1, atr, at3, atx Date and time encoding: 2006-07-24 : 09:14 0000 8050: 34 F8 49 C3 00 01 00 12 00 00 00 00 00 00 00 00 4.I..... ........ 0000 8060: 00 00 00 00 00 00 00 00 49 74 E8 31 F5 C0 D0 AC ........ It.1.... 0000 8070: 80 06 28 07 00 01 00 01 00 0A 01 01 00 00 00 00 ..(..... ........ 0000 8080: 02 03 00 00 02 00 01 16 AF 49 00 00 03 8C 7F D9 ........ .I...... 0000 8090: 26 4F D1 43 00 00 00 00 00 00 00 00 07 00 08 03 &O.C.... ........ 2006-07-24 : 09:14 0000 80A0: 34 F8 49 DA 00 01 00 12 00 00 00 00 00 00 00 00 4.I..... ........ 0000 80B0: 00 00 00 00 00 00 00 00 37 0F 59 2B DB 9E 50 E7 ........ 7.Y+..P. 0000 80C0: 01 00 28 2E 00 02 00 02 00 08 01 01 00 00 00 00 ..(..... ........ 0000 80D0: 02 03 00 00 02 00 01 16 AF 49 00 00 96 7D 33 3A ........ .I...}3: 0000 80E0: 81 4F 34 59 00 00 00 00 00 00 00 00 07 00 08 03 .O4Y.... ........ 2006-07-24 : 09:15 0000 80F0: 34 F8 49 FD 00 01 00 12 00 00 00 00 00 00 00 00 4.I..... ........ 0000 8100: 00 00 00 00 00 00 00 00 A0 02 C7 B3 18 04 7E 51 ........ ......~Q 0000 8110: 01 00 28 B9 00 03 00 03 00 06 01 01 00 00 00 00 ..(..... ........ 0000 8120: 02 03 00 00 02 00 01 16 AF 49 00 00 D8 3D 73 50 ........ .I...=sP 0000 8130: BE D0 CE 7F 00 00 00 00 00 00 00 00 07 00 08 03 ........ ........ When a file is added: Not touched: 0010012.hma _0010012.hma mclist01.hma mclist02.hma _rkidx02.hma Removed: _rkidx03.hma Modified: _hmhifi.hma: A lot of noise. dc278fcb39eab5e97f5d1c5de1aadfc3 himd-current/hmdhifi/trkidx02.hma 8bca8235b1774769d437227a6be78dba mnt/himd/hmdhifi/trkidx02.hma atdata02.hma: Of course the whole data content. Just appended. Starting with "SMPA" trkidx02.hma: 0000 0100: 00 01 00 01 00 00 00 00 0000 0100: 00 02 00 01 00 02 00 00 0000 8020: 00 00 00 00 00 00 00 02 0000 8020: 00 00 00 00 00 00 00 03 0000 80A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 0000 80B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 0000 80C0: 00 00 00 00 00 00 00 03 00 00 00 00 00 00 00 00 ........ ........ 0000 80D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 0000 80E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 0000 80A0: 2E 21 00 00 00 00 00 00 00 04 00 08 00 0A 01 00 .!...... ........ 0000 80B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........ 0000 80C0: 01 03 00 84 00 02 00 02 01 22 10 01 D9 10 00 00 ........ ."...... 0000 80D0: 01 0F 50 00 00 04 00 00 00 14 0E BD 96 C3 33 72 ..P..... ......3r 0000 80E0: B2 53 2B 68 00 00 00 00 00 00 00 00 01 00 40 00 .S+h.... ......@. 0003 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 ........ ........ 0003 0010: 00 00 00 00 00 00 00 00 00 00 00 B1 00 1F 00 00 ........ ........ 0003 0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 ........ ........ 0003 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 ........ ........ 0003 0010: 00 00 00 00 00 00 00 00 00 00 00 B1 00 1F 00 00 ........ ........ 0003 0020: 00 00 00 00 00 00 00 00 00 B4 01 D0 00 26 00 00 ........ .....&.. 0004 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 ........ ........ 0004 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0C ........ ........ And the meta info we already know how to decode: 0004 0040: 84 00 47 00 65 00 74 00 20 00 52 00 65 00 80 05 ..G.e.t. .R.e... 0004 0050: 61 00 64 00 79 00 20 00 46 00 6F 00 72 00 10 06 a.d.y. . F.o.r... 0004 0060: 20 00 54 00 68 00 65 00 20 00 46 00 75 00 10 07 .T.h.e. .F.u... 0004 0070: 74 00 75 00 72 00 65 00 00 00 00 00 00 00 10 00 t.u.r.e. ........ 0004 0080: 84 00 54 00 65 00 6E 00 20 00 57 00 69 00 90 09 ..T.e.n. .W.i... 0004 0090: 74 00 68 00 6F 00 75 00 74 00 20 00 50 00 10 00 t.h.o.u. t. .P... 0004 00A0: 84 00 28 00 44 00 65 00 6D 00 6F 00 20 00 A0 0B ..(.D.e. m.o. ... 0004 00B0: 41 00 6C 00 62 00 75 00 6D 00 29 00 00 00 10 00 A.l.b.u. m.).....