I have some Nikon raw files (.nef) which were rendered useless during a USB transfer. However, the size seems fine and only a handful of bits are shifted - by a value of -0x20 (hex) or -32 (dec).
Some of the files could be recovered later with another Computer from the same Card and now I am searching for a solution to recover the other >100 files, which have the same error.
Is there a regular pattern? The offsets seem to be in intervals of 0x800 (2048 in dec).
Differences between the two files
1. /_LXA9414.dump: 13.703.892 bytes
2. /_LXA9414_broken.dump: 13.703.892 bytes
Offsets: hexadec.
84C00: 23 03
13CC00: B1 91
2FA400: 72 52
370400: 25 05
4B9400: AE 8E
641400: 36 16
701400: FC DC
75B400: 27 07
925400: BE 9E
A04C00: A8 88
AC2400: 2F 0F
11 difference(s) found.
Here are more diffs from other files:
http://pastebin.com/9uB3Hx43
Related
I have code that reads ID3 tags from an mp3 file, but now I have some m4a files. I found some info on the structure of these files, but that doesn't mention ID3 tags.
What's the best resource for m4a file structure?
Is the song metadata in the m4a structure, or in the contained audio file (which appears to be AAC)?
M4A is just a filename extension - it still remains an MP4 container. Which consists of atoms/boxes (not chunks). The best resource is usually the documentation of the vendor himself, followed by experts with long experience, followed by additional details, followed by simplified explanations:
Apple: QuickTime File Format Specification; Metadata
ExifTool: QuickTime ItemList Tags
Multimedia.cx: QuickTime container; § 2.6: Meta data
xhelmboyx: MP4 layout = ISO 14496-1 Media Format
Just Solve the File Format Problem:
MP4, which uses the...
ISO Base Media File Format, which grew from...
QuickTime, which uses the...
Boxes/atoms format
Strictly by standard only the (MP4) container should have the overall metadata and any of the streams inside should not be searched for metadata. However, don't rely on this, and don't ignore potentially valuable metadata that can be in any/all of the streams (video, audio, subtitles, pictures...). Containers are like archives: they contain one or more files - and for each file you're back at where you began, because you have to recursively analyze that file again. AAC is by far not the only possible audio stream/codec - you could also run across an MP3 in an MP4 container.
ID3 can occur in MP4 as atom ID32, as mentioned here, but this is rare and only allows version 2.x, not version 1.
Additionally to the formats own metadata atoms other metadata formats (not specifically aiming at music) can be embedded in the following atoms:
system
atom UUID with value
other atoms
XMP
0xBE 7A CF CB 97 A9 42 E8 9C 71 99 94 91 E3 AF AC
XMP_ or xml or xmlc
Exif
0x05 37 cd ab 9d 0c 44 31 a7 2a fa 56 1f 2a 11 3e or JpgTiffExif->JP2
exif or exfc
IPTC
0x33 c7 a4 d2 b8 1d 47 23 a0 ba f1 a3 e0 97 ad 38 or 0x09 a1 4e 97 c0 b4 42 e0 be bf 36 df 6f 0c e3 6f
8BIM
0x2c 4c 01 00 85 04 40 b9 a0 3e 56 21 48 d6 df eb
360fly
0xef e1 58 9a bb 77 49 ef 80 95 27 75 9e b1 dc 6f
ID3 v2.x
ID32
Mostly the atoms in an MP4 have this layout:
- ftyp
- free
- mdat
+ moov
- mvhd
+ udta
- cprt
+ trak
- tkhd
+ udta
- cprt
+ edts
- elst
+ mdia
- mdhd
- hdlr
+ minf
- smhd
- hdlr
+ dinf
- dref
+ stbl
- stsd
- stts
- stsc
- stsz
- stco
+ meta
- hdlr (mdta)
- mhdr
+ keys
- mdta
- mdta
- mdta...
> ilst
+ (size, index)
- data (type, locale, value)
- itif
- name
- udta
> ctry
> lang
+ trak
https://docs.fileformat.com/audio/m4a/ has some details
https://github.com/ahyattdev/M4ATools has example code
The song meta data is in nested m4a chunks.
I'm an 'Old Timer' that learned to program on a Commodore 64 with a cassette drive (not a disk drive) for storing data. Oh the joy!
I am wondering if there is an equivalent way to perform Peek and Poke commands in a .bat file. Is it even possible anymore to check a specific address the way it worked in BASIC language?
Can a batch file locate the address of something like whether or not the 'y' key has been pressed and can it also set the value of that address to indicate that key was pressed?
It used to be something like PEEK(64324) would return the value of that location. Likewise; POKE(64324) would set the value at that location.
I could run a loop that basically waited for a keyboard input and if it recieved the correect trigger at that address it would perform a command. e.g.
For x = 1 to 1000
If PEEK(64324) = 1 then exit
Next x
So when the 'y' key was pressed, the loop would exit or goto the next command. Can BATCH check a specific address for it's current state and if so, is there any repository or listing somewhere that tells what address is what for things like colors and keys on the keyboard?
In MSDOS you can use the DEBUG tool to get a dump of memory:
SHOWBIOS.BAT
ECHO:d FE00:0000 0040 >debug.txt
ECHO:q >>debug.txt
DEBUG < debug.txt > debug.out
You can run the memory dump thru a script
-d FE00:0000 0040
FE00:0000 41 77 61 72 64 20 53 6F-66 74 77 61 72 65 49 42 Award SoftwareIB
FE00:0010 4D 20 43 4F 4D 50 41 54-49 42 4C 45 20 34 38 36 M COMPATIBLE 486
FE00:0020 20 42 49 4F 53 20 43 4F-50 59 52 49 47 48 54 20 BIOS COPYRIGHT
FE00:0030 41 77 61 72 64 20 53 6F-66 74 77 61 72 65 20 49 Award Software I
-q
Times have changed, indeed, but in fact you could perhaps still do PEEKs and POKEs with the good old Motorola 68k family... because they like the 6502 used memory-mapped I/O.
I could be wrong, but I think computers today largely have abandoned memory-mapped I/O. Instead they'll do something like the Intel 8x86 family. It's been awhile since I took 8086 assembly, though.
Is there a way I can write one value to a double register using LIBMODBUS? For example writing value 100,000 to be spread across one register. Currently using modbus_write_registers to write 10,000 I am sending the modbus message
rc = modbus_write_registers(ctx, 4, 2, tab_reg); (Where tab_reg[0] = 10,000 and tab_reg[1] = 0)
0A 10 00 04 00 02 04 27 10 00 00 DC 09
Ideally the message i believe I would like to send would not send the 00 00 for the zero value. Is this possible to utilise using Libmodbus?
NB - I have also attempted using modbus_write_register() and this produced a much longer message so I am inclined to believe write registerS is the way to go.
F3 c8 42 14 - latitude //05.13637° should be nearby this coordinate
5d a4 40 b2 - longitude //100.47629° should be nearby this coordinate
this is the hex data i get from GPS device, how to convert to readable coordinate?
i don't have any manual document.please help.thanks
22 00 08 00 c3 80 00 20 00 dc f3 c8 42 14 5d a4 40 b2 74 5d 34 4e 52 30 39
47 30 35 31 36 34 00 00 00
this is my full bytes i received,but the engineer told me that F3 c8 42 14 is latitude and 5d a4 40 b2 is longitude
I worked with a Motorola GPS module once and the documentation said that the two hexes represented int types.
In your case, you might want to look at the documentation as well. If you know the model number, you can just google it.
Here is the documentation link for the motorola GPS I used.
Motorola GPS Module
I also took the liberty to do some calculations for you. If your lattitude was indeed
0x1442c8f3
(endianness does make a difference here). The integer equivalent is
339921139
in decimal system. If you divide that by 3600000 milliarcseconds
(where 1 deg = 60 min = 60 * 60 s = 60*60*1000 ms) you get
94.4225386
deg, which is close to your expectations. There isn't enough data to validate it but I believe most of the GPS modules return the milliarcseconds for both latitude and longitude.)
Assuming the hex codes represent unencrypted 32-bit floating point numbers (they might not do), you could try reading them into a C program and printing them out using printf("%f").
Don't forget that the words could have both endianness, i.e. the first one could be F3 C8 42 14 or 14 42 C8 F3 (bytes reversed).
Try it both ways and see if you get anything useful.
I wasn't able to get anything quickly from this online floating point calculator here.
Edit:
Building on Khanal's answer, this link to Latitude/Longitude suggests that the numbers are indeed fixed point and explains the sign convention.
Perhaps more useful for the calculations is HexIt, which allows choosing from a variety of C data types, both integer and floating point, as well as flipping back and forth between little and big endian representations.
I think the values are in 32-bit floating point. However, the bytes are slightly shifted in the stream that you show. Taking longitude first: 100.47629 in 32-bit floating point is 42C8F3DC these are bytes 10 through 13 in your stream (Least significant byte first).
For latitude 5.13637 in 32-bit floating point is 40A45D24 these are bytes 14 through 17 but it's 40A45D14 in the byte stream so it's off a little in the least significant decimal digit (Again, it's least significant byte first).
I am working on a C project in MSVS 2010 (meaning I am using malloc, calloc, and free, not the C++ new and delete operators). I need to find a memory leak(s?), so I've followed the steps on http://msdn.microsoft.com/en-us/library/x98tx3cf.aspx to get the program to dump the memory state at the end of the run.
I include the libraries like so:
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
I also specify that every exit should display the debug info like so:
_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
But my debug output looks like this:
Detected memory leaks!
Dumping objects ->
{80181} normal block at 0x016B1D38, 12 bytes long.
Data: < 7 7 8 7 > 0C D5 37 00 14 A9 37 00 38 99 37 00
{80168} normal block at 0x016ACC20, 16 bytes long.
Data: < 7 H 7 X 7 \ 7 > A8 FB 37 00 48 E9 37 00 58 C2 37 00 5C AC 37 00
...
According to the article, I should be getting file name and line number output indicating where the leaked memory is allocated. Why is this not happening, and how can I fix it?
Adrian McCarthy commented that I should ensure that the definition _CRT_MAP_ALLOC existed in every compilation unit. While I could not figure out how to define that as a compiler option, I did create a sparse header file that I ensured every compiled file included. This made the debugging functionality work as expected.